LP3925 LP3925 High Performance Power Management Unit for Handset Applications Literature Number: SNVS672A LP3925 High Performance Power Management Unit for Handset Applications General Description Features The LP3925 is designed to meet the power management requirements of the latest 3G/GSM/GPRS/EDGE cellular phones. The LP3925 PMU contains a single-input Li-Ion battery charger, 14 low-dropout voltage regulators including 3 wide-input, low-output, regulators, 3 buck regulators, a USB Transceiver, two comparators, two TCXO buffers, SIM level shifter, 12-bit ADC, real time clock, and backup battery charger. Programming is handled via an I2C-compatible high-speed Serial Interface allowing control of program on/off conditions and the output voltages of individual regulators, and to read status information of the PMU. It can charge and maintain a single cell Li-Ion battery operating from an AC adapter or USB power source. The Li-Ion charger requires few external components and integrates the power FET. Charging is thermally regulated to obtain the most efficient charging rate for a given ambient temperature. A built-in Over-Voltage Protection (OVP) circuit at the charger input protects the PMU from input voltages up to +28V eliminating the need for any external protection circuitry. Buck regulators have an automatic switch to ECO mode at low load conditions providing very good efficiency at low output currents. Buck regulators have an automatic switch to ECO mode at low load conditions providing very good efficiency at low output currents. General-type "PERFECT" LDO regulators provide excellent PSRR and ULTRA LOW NOISE, 10 V typ., ideally suited for supplying voltage to RF section. The real-time clock/calendar provides time interval information as well as two programmable alarms. To accommodate different baseband requirements, the LP3925 PMU has different default voltage settings and startup sequences. Two general-purpose comparators can be used for detecting external accessories like ear-phones etc. Power conversion and signal level shifting circuits are provided to allow SIM interfacing. Linear charger with single input -- USB or AC adapter input -- Power routing switch -- 28V OVP on the charger input Three high-efficiency Synchronous Magnetic Buck Regulators, IOUT 800 mA each: -- 2 regulators have DVS support -- High-efficiency ECO mode @ low IOUT -- Auto Mode ECO/PWM switch -- 28V OVP on the charger input 15 LDOs -- 10 General-type Low-Noise LDOs 8 x 300 mA 2 x 80 mA -- Three wide-input low-output (WILO) LDOs, all capable of supplying up to 300 mA -- 1 micro-power LDO with IOUT 30 mA -- 1 high-voltage USB LDO -- S/W controllable outputs -- Outputs configurable for pulldown Two Comparators and Two TCXO Buffers USB 2.0-compatible Transceiver (12 Mb/s) 12-bit A/D Converter for battery management and external monitoring Two over-voltage protected outputs for USB transceivers Real time clock with two alarms SIM card level translator Three controllable current sinks for Keypad LEDs Backup battery charger Thermal Shutdown with Early Warning Alarm Momentary Power Loss detection Interrupt Request to reduce S/W polling 81-bump micro SMDxt package Key Specifications LOW PMU IQ in sleep mode 50 mA to 1200 mA Charging Current from AC Adapter 3.0V to 4.5V Battery Voltage 150 mV typ. Dropout Voltage on LDOs @ 300 mA 2% typ. Output Voltage accuracy on LDOs ULTRA LOW NOISE (10 V typ.), ULTRA LOW IQ, remote capacitor General-type "PERFECT" LDOs 3% accurate Buck regulators up to 90% efficient Applications GSM, GPRS, EDGE, CDMA & 3G Handsets (c) 2011 National Semiconductor Corporation 301204 www.national.com LP3925 High Performance Power Management Unit for Handset Applications July 25, 2011 LP3925 Table of Contents General Description .............................................................................................................................. 1 Features .............................................................................................................................................. 1 Key Specifications ................................................................................................................................ 1 Applications ......................................................................................................................................... 1 Typical Application Diagram ................................................................................................................... 4 Pin Configuration .................................................................................................................................. 5 Package Marking Information ................................................................................................................. 6 Ordering Information ............................................................................................................................. 6 Pin Descriptions ................................................................................................................................... 7 Absolute Maximum Ratings .................................................................................................................... 9 Operating Ratings (Note 1, Note 2) ........................................................................................................... 9 General Electrical Characteristics ........................................................................................................... 9 Current Consumption .......................................................................................................................... 10 Device Operating Modes ..................................................................................................................... 11 Startup and Shutdown Sequences ........................................................................................................ 13 Enable Control ................................................................................................................................... 14 Multifunctional Pins ............................................................................................................................. 14 Single-Input Linear Charger with PMOS Routing Switch ........................................................................... 15 GENERAL CHARGER CONTROL ................................................................................................. 15 CHARGER INPUT DETECTION AND LIMITS ................................................................................. 15 SYSTEM SUPPLY FUNCTION ..................................................................................................... 15 BATTERY CHARGING FUNCTION ............................................................................................... 16 CC TO CV MODE TRANSITION ................................................................................................... 16 END-OF-CHARGE AND RESTART ............................................................................................... 16 POWER ROUTING SWITCH ........................................................................................................ 16 OPERATION WITHOUT BATTERY ............................................................................................... 16 HIGH-CURRENT MODE .............................................................................................................. 16 CHARGER ELECTRICAL CHARACTERISTICS .............................................................................. 21 Buck Information ................................................................................................................................ 22 BUCK CIRCUIT OPERATION ....................................................................................................... 22 PWM OPERATION ...................................................................................................................... 22 INTERNAL SYNCHRONOUS RECTIFICATION .............................................................................. 22 CURRENT LIMITING ................................................................................................................... 22 ECO MODE OPERATION ............................................................................................................ 22 BUCK OUTPUT VOLTAGE SELECTION ........................................................................................ 23 EXTERNAL COMPONENT SELECTION ........................................................................................ 24 DVS CONTROL .......................................................................................................................... 24 BUCK TYPICAL PERFORMANCE PLOTS ..................................................................................... 25 BUCK ELECTRICAL CHARACTERISTICS ..................................................................................... 27 LDO Information ................................................................................................................................. 28 GENERAL-TYPE "PERFECT" LDOs .............................................................................................. 28 WILO-TYPE LDOs ....................................................................................................................... 28 MICRO-PWR LDO ....................................................................................................................... 28 USB LDO ................................................................................................................................... 28 GENERAL LDO ELECTRICAL CHARACTERISTICS ....................................................................... 28 WILO-TYPE LDO ELECTRICAL CHARACTERISTICS ..................................................................... 29 MICRO-PWR LDO ELECTRICAL CHARACTERISTICS .................................................................... 30 USB LDO ELECTRICAL CHARACTERISTICS ................................................................................ 30 USB Transceiver ................................................................................................................................ 31 USB TRANSCEIVER ................................................................................................................... 31 USB CHARGER DETECTION ....................................................................................................... 31 USB CHARGER DETECTION ELECTRICAL CHARACTERISTICS .................................................... 35 USB TRANSCEIVER ELECTRICAL CHARACTERISTICS ................................................................ 35 TCXO Buffers .................................................................................................................................... 36 TCXO BUFFER ELECTRICAL CHARACTERISTICS ........................................................................ 36 Backup Battery Charger ...................................................................................................................... 37 MOMENTARY POWER LOSS ...................................................................................................... 37 32.768 kHz CRYSTAL OSCILLATOR ............................................................................................. 37 BACKUP BATTERY CHARGER ELECTRICAL CHARACTERISTICS ................................................. 37 Real Time Clock ................................................................................................................................. 38 USIM Interface ................................................................................................................................... 39 USIM LEVEL TRANSLATOR ELECTRICAL CHARACTERISTICS ..................................................... 39 FIGURE 21. SIM Interface Level Shifters ........................................................................................ 40 Comparators ...................................................................................................................................... 40 www.national.com 2 40 40 40 40 41 41 41 42 42 42 42 43 43 43 43 44 44 44 44 44 45 45 45 45 46 48 List of Figures FIGURE 1. Device Operating Modes ............................................................................................................ FIGURE 2. Startup and Shutdown Sequences ................................................................................................ FIGURE 3. Charging Cycle voltage and Current Plots ....................................................................................... FIGURE 4. Charger Power Structure ............................................................................................................ FIGURE 5. Charger Charging Cycle Operation Description ................................................................................. FIGURE 6. Charger Internal Power Switch Operation Description When Charger is Off ............................................... FIGURE 7. Charger Internal Power Switch Operation Description When Charger is On ............................................... FIGURE 8. Charger Block Diagram .............................................................................................................. FIGURE 9. Charger CC to CV Mode Transition Diagram .................................................................................... FIGURE 10. Typical PWM Operation ............................................................................................................ FIGURE 11. Typical ECO Operation ............................................................................................................ FIGURE 12. Buck's Switches Controlling Diagram ........................................................................................... FIGURE 13. Typical ECO Operation ............................................................................................................ FIGURE 14. Typical Ripple in ECO Mode ...................................................................................................... FIGURE 15. USB Transceiver Block Diagram ................................................................................................. FIGURE 16. USB Transceiver Configured to 3-Pin Interface ............................................................................... FIGURE 17. USB Transceiver Configured to 4-Pin Interface ............................................................................... FIGURE 18. USB Transceiver Configured to 5-Pin Interface ............................................................................... FIGURE 19. BBC IU Characteristics ............................................................................................................. FIGURE 20. RTC Functional Block Diagram ................................................................................................... FIGURE 21. SIM Interface Level Shifters ....................................................................................................... FIGURE 22. LP3925 ADC Temperature Range ............................................................................................... FIGURE 23. Typical REF_OUT BatteryTemperature MeasurementApplication Diagram .............................................. FIGURE 24. Current Sinks PWM Control ....................................................................................................... FIGURE 25. Bit Transfer ........................................................................................................................... FIGURE 26. Start and Stop Conditions ......................................................................................................... FIGURE 27. Bus Acknowledge Cycle ........................................................................................................... FIGURE 28. Register Write Format .............................................................................................................. FIGURE 29. Register Read Format .............................................................................................................. 3 12 13 17 17 18 18 19 20 20 22 22 23 23 23 31 32 33 34 37 38 40 41 42 43 44 44 44 46 46 www.national.com LP3925 COMPARATOR ELECTRICAL CHARACTERISTICS ....................................................................... ADC ................................................................................................................................................. A/D CONVERTER DATA AND CONTROL REGISTERS ................................................................... BATTERY DISCHARGE CURRENT MEASUREMENT ..................................................................... JUNCTION TEMPERATURE MEASUREMENT ............................................................................... OTHER ITEM CURRENT VOLTAGE MEASUREMENT .................................................................... ADC ELECTRICAL CHARACTERISTICS ....................................................................................... Reference Output ............................................................................................................................... REFERENCE BUFFER ELECTRICAL CHARACTERISTICS ............................................................. UVLO Operation ................................................................................................................................. Current Sinks ..................................................................................................................................... Support Functions ............................................................................................................................... REFERENCE ............................................................................................................................. OSCILLATOR ............................................................................................................................. THERMAL SHUTDOWN .............................................................................................................. I2C-Compatible Serial Bus Interface ...................................................................................................... INTERFACE BUS OVERVIEW ...................................................................................................... DATA TRANSACTIONS ............................................................................................................... START AND STOP ...................................................................................................................... ACKNOWLEDGE CYCLE ............................................................................................................. "ACKNOWLEDGE AFTER EVERY BYTE" RULE ............................................................................. ADDRESSING TRANSFER FORMATS .......................................................................................... CONTROL REGISTER WRITE CYCLE .......................................................................................... CONTROL REGISTER READ CYCLE ........................................................................................... REGISTER READ AND WRITE DETAIL ......................................................................................... Physical Dimensions ........................................................................................................................... LP3925 Typical Application Diagram 30120401 www.national.com 4 LP3925 Pin Configuration 30120402 LP3925 (Top View) * Pins that can be programmed as analog pins (default as accordance of the interface used, either 3-wire or 5-wire. All stated in pin configuration) or digital input/output pins. Pins these pins except SINK1, 2, 3 and INP1, 2 can be used as that are used for USB transceiver interfacing are chosen in ADC inputs. 30120404 5 www.national.com LP3925 Package Marking Information 30120403 Ordering Information Order Number Product Identification Supplied as LP3925RME/NOPB 3925 250 Tape & Reel LP3925RMX/NOPB 3925 1000 Tape & Reel LP3925RME-A/NOPB V030 250 Tape & Reel LP3925RMX-A/NOPB V030 1000 Tape & Reel LP3925RME-E/NOPB V030 250 Tape & Reel LP3925RMX-E/NOPB V030 1000 Tape & Reel www.national.com 6 LP3925 Pin Descriptions Name Pin # Type BATT C1, D1 P Main battery connection. Description D- E1 A USB Differential Data Line (-) Input/Output. D+ F1 A USB Differential Data Line (+) Input/Output. DATA/VP* G2 DI/O FB_B1 H1 A Buck1 Feedback. FB_B2 H3 A Buck2 Feedback. FB_B3 H5 A Buck3 Feedback. GND E5 G Ground GND_B1 H2 G Power Ground for Buck1. GND_B2 G4, H4 G Power Ground for Buck2. GND_B3 G6, H6 G Power Ground for Buck3. GND_SINK F7 G Ground of GPIO current sink. HF_PWR D4 DI Input for triggering startup. Power up sequence starts when this pin is set HIGH. Internal 500 k pull-down resistor. INP1* F5 A Comparator 1 input INP2* F6 A Comparator 2 input IRQ_N G5 DO LDO_UPWR B5 A Internal supply output, fixed to 1.8V. Can be loaded externally, max 30 mA. LDO1 A5 A LDO1 Output LDO10 G9 A LDO10 Output LDO11 H9 A LDO11 Output LDO12 J9 A LDO12 Output LDO13 J7 A LDO13 Output LDO2 A7 A LDO2 Output LDO3 A8 A LDO3 Output LDO4 B8 A LDO4 Output LDO5 A9 A LDO5 Output LDO6 C9 A LDO6 Output LDO7 D9 A LDO7 Output LDO8 C8 A LDO8 Output LDO9 F9 A LDO9 Output OE_N* E2 DI USB Output Enable input. Active LOW enables the transceiver to transmit data onto the bus. A HIGH input enables receive mode. OSC_32KHZ* D3 DO Buffered 32 kHz clock signal output. PS_HOLD H7 DI Control input for Power Up/Power Down sequences of PMU. Internal 500 k pull-down resistor by EEPROM default. Can be configured as pull-up as well. PWR_ON B3 DI Power button input. Power up sequence starts when this pin is set HIGH. Internal 500 k pull-down resistor. RCV* E3 DO Receive Data: Single ended output from USB differential data lines for 5 wire USB. REF_OUT H8 A 2.5V Reference output RSENSE* F4 A Sense resistor input pin for charge/discharge current measurement RSTIN_N B7 DI Reset button input, active low. Internal 500 k pull-up resistor. RSTOUT_N C6 DO Reset output, active low. Pin stays LOW during power up sequence. SCL F3 DI Serial interface clock input; requires external pullup, 1.5 k typ. SDA G3 DI/O Data input/output for 3 wire USB transceiver/ USB Interface Plus Input/Output for 5 wire USB. If OE_N = HIGH, VP is a receiver output (+), If OE_N = LOW, VP is a driver input (+). Interrupt output, active LOW. Open Drain output, external pull up resistor is needed, typ. 10 k. Serial interface bi-directional data; requires external pullup, 1.5 k typ. 7 www.national.com LP3925 Name Pin # Type Description SEO/M* F2 DI/O Data input/output for 3 wire USB transceiver/ USB Interface Minus Input/Output for 5 wire USB. If OE_N = HIGH, VM is a receiver output (-), If OE_N = LOW, VM is a driver input (-). SEL D5 DI Select input for default option at power up SIM_CLK* D7 DO SIM card connection. Level shifted clock signal to SIM SIM_CLK_IN* E7 DI SIM clock input from Baseband Processor SIM_DATA* E8 D SIM data input/output from Baseband Processor SIM_IO* D8 D SIM card connection. SIM Card Data input/output SIM_RST* D6 DO SIM card connection. Level shifted reset signal to SIM SIM_RST_IN* E6 DI SIM reset input from Baseband Processor SINK1* G8 A Current sink input 3. SINK2* F8 A Current sink input 2. SINK3* G7 A Current sink input 3. SLEEP_N (TCXO_EN) C7 DI Sleep mode input, active low. Internal 500 k pull-up resistor by EEPROM default. Can be configured as pull-down as well. SPND* E4 DI USB Suspend mode control input for 5 wire USB. A logical high at SUSPEND will power down the differential receiver and VP and VM will remain active with reduced current consumption. SW_B1 J2 A Buck1 Output. SW_B2 J4 A Buck2 Output. SW_B3 J6 A Buck3 Output. TCXO1_I* B6 A TCXO1 buffer input. TCXO1_O* C3 DO TCXO2_I* C5 A TCXO2_O* C4 DO USB_GND G1 G USB Ground VCOIN B4 A Back up battery Charger Output. Connection of external coin cell (2.5 or 3.0V). VDD A1, B1 P Output for system power. VIN_B1 J1 P Input for Buck1 VIN_B2 J3 P Input for Buck2 VIN_B3 J5 P Input for Buck3 VIN_CHG A2, B2, C2 P DC power input to charger block from wall, car power adapter or USB. Requires 1F capacitor to ground. VIN1 A6 P Input for LDOs VIN2 B9 P Input for LDOs VIN3 E9 P Input for LDOs VIN4 J8 P Input for LDOs VTRM D2 A USB Reference supply output (3.3 V). Requires 1F capacitor to GND for stability. LDO14 XIN A3 A External Crystal Oscillator In XOUT A4 A External Crystal Oscillator Out Buffered and validated TCXO1 output clock signal. TCXO2 buffer input. Buffered and validated TCXO2 output clock signal. *Pins that can be programmed as analog pins (default as stated in pin configuration) or digital input/output pins. Pins that are used for USB transceiver interfacing are chosen in accordance of the interface used, either 3-wire or 5-wire. All these pins except SINK1, 2, 3 and INP1, 2 can be used as ADC inputs. A: D: I: DI/O G: O: P: www.national.com Analog Pin Digital Pin Input Pin Digital Input/Output Pin Ground Output Pin Power Connection 8 Operating Ratings 2) VIN_CHG BATT, PRSW, VIN_B1, VIN_B2, BIN_B3 VCOIN VIN1, VIN2, VIN3 VIN4 Junction Temperature Range Maximum Ambient Temperature (Note 3) Maximum power dissipation (Note 3) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VINCHG to GND BATT, VIN_B1, VIN_B2, VIN_B3, VCOIN, VIN1, VIN2, VIN3, VIN4 SEL Other input-only pins Junction Temperature (Note 5) Storage Temperature Maximum continuous power dissipation VIN_CHG, BATT, HF_PWR, PWR_ON, RSTIN_N, D+, D-, RSENSE, SIM_IO, SIM_CLK, SIM_RST, GND_USB (Note 4) All other (Note 4) -0.3V to +28V -0.3V to +6V -0.3V to +2V 0.3V to +6V 150C -65C to +150C (Note 1, Note 2) 4.5V to 6.5V 3.0V to 4.5V 1.9V to 4.5V 2.5V to 4.5V 1.0V to 4.5V -40C to +125C -40C to +85C 1.72W 32C/W Package Thermal Resistance JA (Note 5) 8kV HBM 2kV HBM General Electrical Characteristics Typical values and limits appearing in normal typeface are for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation TJ = -40C to +125C). Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter Conditions Typ Limits Min Max 3.0 3.25 Units UNDER VOLTAGE LOCK-OUT UVLO Range-to-range accuracy VIN Rising; UVLO LEVEL programmed to 3.10V V LOGIC AND CONTROL INPUTS VIL Input Low Level VIH Input High Level VIL Multifunctional Pins Low Level VIH Multifunctional Pins High Level 0.25* VLDO1 SDA (Note 7), SCL (Note 7), OE_N, DATA/VP, SEO/VM, SPND PWR_ON, RS_HOLD, SLEEP_N, HF_PWR, RSTIN_N V 1.08 SDA (Note 7), SCL (Note 7), OE_N, DATA/VP, SEO/VM, SPND 0.75* VLDO1 PWR_ON, RS_HOLD, SLEEP_N, HF_PWR, RSTIN_N V 1.32 0.6 When configured as logic inputs. V 1.6 3.0 -5 +5 SEL input between 0V and 1.8V. ILEAK RIN Input Current Input Resistance Other logic inputs without internal pullup or pulldown resistors between 0V and VDD at 3.6V. PWR_ON, HF_PWR, PS_HOLD, RSTIN_N, SLEEP_N (TXCO_EN) pullup or pulldown resistors (if configured) 9 500 A k www.national.com LP3925 Absolute Maximum Ratings (Note 1, Note LP3925 Symbol Parameter Conditions Typ Limits Min Max Units LOGIC AND CONTROL OUTPUTS VOL Output Low Level RSTOUT_N, RCV, DATA/VP, SEO/ VM, IRQ_N IOUT = 2mA 0.25* VLDO1 SDA (Note 7) V 0.25* VLDO1 VOH Output High Level RCV, DATA/VP, SEO/VM IOUT = 2mA IOH Output High Leakage SDA (Note 7), RSTOUT_N, IRQ_N VOH = VLDO1 0.75* VLDO1 V 10 A use in innovative and environmentally friendly designs, giving the end user the possibility of increased consumer device working time and thus a crucial advantage of the rapidly developing mobile market. The quiescent currents in standby and sleep modes are stated in the CURRENT CONSUMPTION ELECTRICAL CHARACTERISTICS below. Current Consumption Current consumption of the LP3925 PMU has been one of the main features this device is famous for. It is mainly because of ultra low IQs in sleep and standby modes the LP3925 can ensure dramatic power savings and prolong battery life for enormous amount of time. Due to such a significant advantage in these critical factors, an LP3925 is very convenient to CURRENT CONSUMPTION ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter Conditions Typ. Limit Min Max Units CURRENT CONSUMPTION IQ(STANDBY) Battery Standby Current IQ(SLEEP) Battery Current in SLEEP mode @ 0 load VIN = 3.6V ICOIN = 0A 3.5 LDO1 ON 60 A Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables. Note 2: All voltages are with respect to the potential at the GND pin. Note 3: The Maximum power dissipation depends on the ambient temperature and can be calculated using the formula P = (TJ - TA)/JA where TJ is the junction temperature, TA is the ambient temperature, and JA is the junction-to-ambient thermal resistance. The 1.72W rating appearing under Maximum Ratings results from substituting the Maximum junction temperature, 125C, for TJ, 70C for TA, and 32C/W for JA. More power can be dissipated safely at ambient temperatures below 70C. Less power can be dissipated safely at ambient temperatures above 70C. The Maximum power dissipation can be increased by 31 mW for each degree below 70C, and it must be de-rated by 31 mW for each degree above 70C. Note 4: The Human body model is a 100 pF capacitor discharged through a 1.5 k resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin. MIL-STD-883 3015.7 Note 5: Internal thermal shutdown protects the device from permanent damage. Thermal shutdown engages at TJ = 150C (typ.) and disengages at TJ=130C (typ). Note 6: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production with TJ = 25C. All hot and cold limits are guaranteed by correlating the electrical characteristics to process and temperature variations and applying statistical process control. Note 7: Guaranteed by design. Note 8: Dropout voltage is the input-to-output voltage difference at which the output voltage is 100 mV below its nominal value. This specification does not apply in cases it implies operation with an input voltage below the minimum appearing under Operating Ratings. For example, this specification does not apply for devices having 1.5V outputs because the specification would imply operation with an input voltage at or about 1.5V. Note 9: Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists, special care must be paid to thermal dissipation issues in board design. Note 10: Guaranteed for output voltages no less than 1.0V www.national.com 10 POWER-ON-RESET: All internal registers are reset to default values. This is the default state after applying power to the PMU, duration 1ms. STANDBY: All functions disabled (except RTC power management); PMU is in low power mode. START UP: Startup sequence is triggered by setting PWR_ON input high for 100 ms or by setting HF_PWR input high for 100 ms or by connecting a suitable voltage to charger input. For MPL or RTC ALARM events the startup sequence begins after 2ms delay from the MPL or RTC ALARM events. During the sequence the regulators on PMU are enabled according to a pre-programmed timing pattern. If the regulators are enabled, RSTOUT_N is released, allowing the application processor to start up. PS_HOLD must be set high in 1.5 seconds from the start of STARTUP. The input signal witch activates startup must stay on until PS_HOLD asserted. If PS_HOLD is not asserted in 1.5 seconds then SWHUTDOWN is initiated. For PWR_ON startup there is no 1.5 seconds limit. IDLE: PMU goes to normal working mode, if PS_HOLD is pulled HIGH after releasing RSTOUT_N. In this mode all features and control interfaces are available to the user. Chip temperature over TSDH, VDD voltage below UVLO, PS_HOLD going low for 10 ms or a flag failure in a monitored regulator for 10 ms will cause the PMU to go to SHUTDOWN state. SLEEP: PMU goes to SLEEP state from IDLE state, if SLEEP_N input is pulled low. In this mode PMU current consumption is minimized to extend device's standby time. Load on regulators and bucks should stay below 5mA each. Conditions of going to SHUTDOWN state are the same as in IDLE state.. SLEEP Mode is controlled by the Serial Interface. SHUTDOWN: In this state RSTOUT_N is pulled LOW and all regulators are disabled according to pre-programmed timing pattern. After this, all registers are reset to default values, and PMU goes to STANDBY state. SYSTEM RESET: PMU goes to SYSTEM RESET mode if RSTIN_N input has been pulled low for 33 ms. In this mode RSTOUT_N output is pulled low and user registers are reset. After a pre-programmed time delay RSTOUT_N is released, allowing the application processor to start up. During SYSTEM RESET, the LP3925's always-on power rail will not drop to zero. If for some reason PS_HOLD is pulled down during reset, it must come back up within 1.5s of the beginning of system reset. If EN RSTIN SHUTDOWN bit is high then the reset sequence is similar to shutdown and will startup again only if EN RSTIN STARTUP bit is high. 11 www.national.com LP3925 Device Operating Modes LP3925 30120405 FIGURE 1. Device Operating Modes www.national.com 12 LP3925 Startup and Shutdown Sequences 30120406 FIGURE 2. Startup and Shutdown Sequences The default, factory-programmed power-up sequence of the PMU can be seen in Figure 2. Startup sequence is triggered by setting PWR_ON or HF_PWR input high for 100 ms or after 500 ms is passed from the connection of a suitable voltage to the charger input. Once this time has expired, the start-up time slots begin. The programmable values of the startup and shutdown time slots are available in the Default Operating Settings section at the end of the datasheet. If the Idle state has been reached from the Startup state, all regulators that are enabled are on, and their outputs are defined by their programmed register values. 450 s in startup/shutdown diagram is the time needed for system to perform a shutdown event. Note: All the timings are limited by an internal oscillator's accuracy. 13 www.national.com LP3925 Example 2: Goal - Enable LDO9, LDO10 and TCXO buffer1 together with one register write. One possible solution: write LDO9 CONTROL, LDO10 CONTROL and TCXO1 CONTROL to 0010; now writing '11' to address 0x00 bits [1:0] enables all three blocks. Enable Control LP3925 provides much flexibility in enabling/disabling on-chip features. The blocks that have advanced enable controls include: LDOs, buck regulators, USB transceiver, TCXO buffers, SIM level shifter. Each block has a 4-bit code in registers, which selects the enable signal for that block. These codes are in register addresses 0x37...0x41, with bit names ending with CONTROL. The enable signal translation table is stated below. In order to make the control more flexible, there is a possibility for the blocks to be enabled through registers 0x00...0x02 or through multifunctional pins. One control signal can enable any number of features. This allows to group signals so, that any end-system function can be switched on with only one input or register write. There are additional enable controls for sleep mode operation with ALLOW IN SLEEP bits in register addresses 0x34...0x36. If a block is not allowed in sleep mode, then this block is always off during sleep. If a block is allowed in sleep mode, then it is controlled by its selected enable signal, and does not depend on sleep mode. Example 1: Goal: Buck2 is always disabled in sleep mode and enabled in idle mode. Best solution: write BUCK2 CONTROL to '0001' and ALLOW BUCK2 IN SLEEP to '0'; now Buck2 is enabled in working mode and disabled in sleep mode, with no separate enable bit/input. Pin/Code 1000 1001 1010 Multifunctional Pins Some pins corresponding to 32 kHz oscillator, USB transceiver, SIM interface, TCXO buffer, current sink and comparator blocks along with RSENSE pin are multifunctional pins, which means that they can be programmed as analog function pins, ADC inputs or digital input/output pins. These pins can be configured from registers 0x19..0x23. If one block uses more than one pin, then all the pins must be configured for the block to work. For example, all 6 SIM level shifter pins must have level shifter function selected, before the block is connected to the pins. To use USB with 4- or 5wire interface, the used pins must all be configured as 5-wire USB pins. For 3-wire interface the 3 pins must all be configured as 3-wire USB pins. Some GPIO functions have separate enable controls. These enables will take the blocks to a shutdown state, but will not disconnect them from the pins. The GPIO configuration options are described in the table below. 1011 OSC_32 KHZ RSENSE 1100 1101 12 mV 26.4 mV 39.6 mV 56.4 mV 81.6 mV SIM RST, baseband side SIM_CLK _IN SIM CLK, baseband side SIM_DATA 98.4 mV 120 mV SIM I/O, baseband side SIM_RST SIM RST, SIM side SIM_CLK SIM CLK, SIM side SIM_IO SIM I/O, SIM side TCXO1 warmup time before output enable TCXO1_I 1s 21 s 41 s 61 s TCXO1 output driver strength TCXO1_O TCXO2_O 1111 Maximum measurable voltage drop on sense resistor N/A SIM_RST_IN TCXO2_I 1110 32 kHz OSC x8 x4 x2 x1 TCXO2_I warmup time before output enable TCXO2in wait=1s TCXO2in wait=21 s TCXO2in wait=41 s TCXO2in wait=61 s TCXO2 output driver strength TCXO2out strength=1 TCXO2out strength=2 TCXO2out strength=4 TCXO2out strength=8 OE_N OE_N: 3-pin USB interface DATA/VP DATA: 3-pin USB interface OE_N: 5-pin USB interface VP: 5-pin USB interface SEO/VM SEO: 3-pin USB interface VM: 5-pin USB interface RCV N/A RCV: 5-pin USB interface SPND N/A SUSP: 5-pin USB interface INP1 INP2 www.national.com Comparator1 input comparison threshold 0.4V 0.6V 0.8V 1.0V 1.2V 1.5V 1.8V 2.4V 1.8V 2.4V Comparator2 input comparison threshold 0.4V 0.6V 0.8V 1.0V 14 1.2V 1.5V SINK1 SINK2 SINK3 1000 1001 1010 31mA 63 mA 94 mA 1011 1100 1101 1110 1111 188 mA 219 mA 250 mA 75 mA 88 mA 100 mA 75 mA 88 mA 100 mA Current sink1 max current output 125 mA 156 mA Current sink2 max current output 13 mA 25 mA 38 mA 50 mA 63 mA Current sink3 max current output 13 mA 25 mA 38 mA 50 mA 63 mA The charger is capable of limiting input current, allowing to accommodate different voltage sources (wall adapters, USB, etc). IDCIN bits set the maximum input current. The sum of system supply and battery charging currents will not go over this limit during normal operation. For correct operation, IDCIN should be set to 235mA or more above IBATT (though this margin can be reduced for IDCIN below 500 mA; e.g. down to 85 mA at IDCIN = 135 mA). High current mode ignores the input current limit. Some of the GPIO pins can be configured as a dedicated charger input status signal output. This signal is low, if charger input is in working range. The 'Inverted VDCIN' configuration details are in the GPIO chapter of the datasheet. Single-Input Linear Charger with PMOS Routing Switch LP3925 has a built-in Li-Ion/Li-Poly battery management system. Its main features are: * 1 input with many current limit options to accommodate different USB and adapter types * Separate supply branches for battery and system * Integrated power routing switch * Charging cycle with precharge, constant current and constant voltage modes * Selectable battery regulation voltage to accommodate different batteries * Selectable system regulation voltage * Wide array of battery charging current options * Flexible charging cycle control * Temperature monitoring to avoid overheating * Selectable safety timer SYSTEM SUPPLY FUNCTION system supply regulator starts to regulate voltage on VDD pin. The voltage is selectable with VDD control bits. System voltage regulator will work as long as charger input is in working range. The only exception is the case, where PMU is in standby mode and system supply is configured off in standby. Because system and battery are supplied from separate branches, the VDD and BATT voltage levels can be different. This means, that the selected voltage can be supplied to VDD and the PMU can fully operate, while the battery is deeply discharged and the charger is in pre-charge mode. In that case the system should not use modes, which will require more current, than the input can provide. System supply is with higher priority than battery charging. This means that if the sum of system and battery currents starts to go over the input limit, then battery charging current will be reduced to stay within the input loading limit. If the system supply reaches the selected input current limit, then the power routing switch will be turned ON. This will connect the battery to the system, which will provide the extra power needed. Also, the system supply current limit will change from input current limit (IDCIN bits) to battery current limit (IBATT bits). This ensures, that if the system load drops, then the battery will not be charged with too large current. In some systems it may be practical to disable the input current limit, so the system can draw more than 1.2A without turning the switch ON. The SYSTEM SUPPLY CURLIM OFF bit can be used for this purpose. Warning: continuous high current draw from the input may cause the PMU to shut down because of high temperature. There is a configuration option for the system supply during PMU's standby mode. The selection for a specific product is shown in Datasheet Addendum document. This option has following behavior: a) supply on during PMU standby: VDD is supplied from BATT via switch (if charger is not working) or from system supply branch (if charger is working). b) supply off during PMU standby: VDD is isolated from BATT pin during PMU standby and system supply branch is disabled. GENERAL CHARGER CONTROL The charger control is divided into two separate parts: battery charging and system supply. Battery charging part of the charger measures battery voltage and current. Based on this data, it makes the decisions about starting or ending battery charging and choosing the right current. System supply part monitors the power consumption by the external system, ensures that the system supply is stable and that the charger input is not overloaded. These systems work independently from each other. If the power routing switch is OFF (non-conducting), then they can be viewed as two separate systems. The only dependence between the two is, that battery charging current can be reduced, if the system requires more current from the input. If the power routing switch is turned ON, then the two algorithms still work independently, but the system supply part is in control of the whole charger. The battery charging part is in the situation, that it still does make battery charging cycle decisions, but these do not affect the actual charging. If the switch is turned OFF again, then the two systems keep on working separately. CHARGER INPUT DETECTION AND LIMITS Input detection is implemented with 2 comparators. One compares the input voltage to the lower limit of the working range, the other to the higher limit of the working range. If the input voltage is between these two levels, then the charger is allowed to work. The lower limit of input's working range is VBATT+200 mV, with an option to add a 4.2V minimum requirement. The higher limit of input's working range can be one of the following values: 6.15V, 6.64V, 7.18V, 7.71V, 10.28V, 15.38V, 18.45V or disabled. To get the exact information about your product, please refer to the Datasheet Addendum document. 15 www.national.com LP3925 Pin/Code LP3925 stop charging at any time. Only one of these bits must be written to '1' at once. Automatic control utilizes internal battery monitoring, which can be configured trough control registers. Automatic end-of-charge requires that the battery has reached termination level. Then the charger starts monitoring battery charging current and comparing it to end-of-charge current (set by ABS EOC and EOC LEVEL bits). If the charging current is below this level for the duration of EOC TIME, then the automatic end-of-charge condition has been reached. Automatic restart requires that one charging cycle has already been completed and the charger is in standby mode. Then the charger monitors battery voltage and compares it to restart level (set by RESTART LEVEL). If the battery voltage is below this level for the duration of RESTART TIME, then the automatic restart condition has been reached. In manual-only mode it is possible to get automatic cycle control information via interrupts. CHARGE STOP INT is generated, if end-of-charge condition has been reached, and CHARGE START INT is generated, if restart condition has been reached). BATTERY CHARGING FUNCTION LP3925 has a safe and smart Li-Ion/Li-Poly battery charge management system, keeping the number of battery charging cycles to a minimum and thus increasing battery lifetime. Following the correct detection of a voltage at the charger input, the charger enters precharge mode. In this mode the battery is charged with a small constant current. Precharge settings are available in register 0x82 and these values are remembered as long as the PMU has power. CHARGER IPRECHARGE bits select the battery current in precharge mode. It should be noted, that value '00' disables precharge current completely. CHARGER VFULLRATE bits select the level, from which the battery can be charged with full charging current. If battery voltage reaches that level, then the charger will move on to full charging mode. CHARGER TPRECHARGE sets the maximum precharge time, after which the battery will be isolated, protecting it from further charging. In full charging mode full rate constant current is applied to the battery, to raise the voltage to the termination level (selected by VTERM bits). The maximum charging current is selectable via IBATT bits, but the actual current can be lower than this limit, depending on the load of system branch. When termination voltage is reached, the charger enters constant voltage mode and a constant voltage is maintained. Now charging current is monitored to detect the end-of-charge condition. After reaching this condition, charger disables the battery charging branch and enters standby mode. FULL TIMEOUT sets the maximum full charge duration, after which the charging will be ended automatically. Then the charger enters standby mode, where the battery is isolated and the charger monitors battery voltage. If restart conditions have been met, then the charging cycle is re-initiated to re-establish the termination voltage level. In standby mode the battery is isolated and the charger monitors battery voltage. POWER ROUTING SWITCH This switch separates the battery from the system. This helps to conserve charge and reduce the count of charge-discharge cycles. If charger input is not connected, then the switch is in ON (conducting) state. In normal conditions the switch is OFF during charger operation. The switch will be turned ON, if the system load is greater than the charger can supply. This event also generates a SWITCH AUTO ON interrupt. If the switch is turned ON during charger operation, then it does not turn back OFF automatically. The only exception to that rule is, if the PMU enters standby mode. If the charger is operating and the switch is turned ON, then only system supply branch is working. Maximum output current is then set by IBATT code, to avoid too high current into the battery. If the charger is working, then power routing switch state can be controlled manually with SWITCH ON and SWITCH OFF command bits. It is advisable to use the SWITCH ON command before the system enters a mode, which draws more current than the input can provide. This will help to avoid voltage drop on VDD, before the internal overload detection reacts. If the system returns to low consumption mode, the SWITCH OFF command bit should be used to restore normal charger operation. CC TO CV MODE TRANSITION CC to CV mode transition is shown on Figure 8. The voltage level of charging mode change (CC to CV) is dependent on both VTERM (0x47, bit3-0) and IBATT (real charging current) settings, equation shows below: VCCtoCV = VTERM - (IBATT*0.05) where 0.05 stands for charger's internal resistance. This equation is valid only when the power routing switch is in non conducting state and the charging is done through charger's branch. When the switch is ON, the charging is done through the supply branch, and the internal resistance in the equation is replaced by the power routing switch's ON resistance. Note that the IBATT current in equation is the real battery charging current which may differ from the programmed one. USER can use ADC to measure charging current and BATT pin voltage. OPERATION WITHOUT BATTERY The charger is not aware of battery presence, it always behaves by the same configuration. If the battery is not connected, then it is recommended to keep the battery charging part disabled. This can be done by disabling the restart timer and ending the charging with STOP CHARGING bit. Otherwise the charger will keep trying to regulate the voltage on BATT pin, causing frequent charging cycles. END-OF-CHARGE AND RESTART Ending and re-starting the charging cycle can be accomplished in multiple ways. Automatic control can be enabled with AUTOMATIC START/ STOP bit. If this bit is '0', then the charging cycle can only be controlled manually. Writing this bit to '1' enables fully automatic cycle control. Manual control is always available via STOP CHARGING and START CHARGING bits. These control bits are write-only and not tied to any internal monitoring, allowing to start and www.national.com HIGH-CURRENT MODE If HIGH-CURRENT MODE bit is set, then the charger enters special high load mode. In this mode the power routing switch is set ON, input current limit is disabled, and the charger branches are working together. All charging cycle controls do not have any effect in high current mode. 16 LP3925 30120408 FIGURE 3. Charging Cycle voltage and Current Plots 30120412 FIGURE 4. Charger Power Structure 17 www.national.com LP3925 30120413 FIGURE 5. Charger Charging Cycle Operation Description 30120414 FIGURE 6. Charger Internal Power Switch Operation www.national.com 18 LP3925 Description When Charger is Off 30120415 FIGURE 7. Charger Internal Power Switch Operation Description When Charger is On 19 www.national.com LP3925 30120416 FIGURE 8. Charger Block Diagram 30120418 FIGURE 9. Charger CC to CV Mode Transition Diagram www.national.com 20 Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ =-25C to +85C. Unless otherwise specified, the following applies for VVIN_CHG = 5.0V.(Note 6, Note 9) Symbol VOV Parameter Over-Voltage Protection threshold Conditions Typ Charger input is turned off if voltage is above this threshold. 6.95 VVIN_CHG AC input voltage operating range VOK_CHG VIN_CHG OK trip-point VTERM VTERM voltage tolerance default VTERM = 4.2V, ICHG = 50 mA VTERM is measured at 10% of the programmed ICHG current Programmable full-rate charge current 6.5V VVIN_CHG 4.5V V BATT < VVIN_CHG - VOK_VIN_CHG V FULL_RATE < VBATT < VTERM (Note 10) ICHG Full-rate charge current tolerance VVIN_CHG - VBATT (Rising) 300 VVIN_CHG - VBATT (Falling) 90 Limit Units Min Max 6.55 7.4 V 4.5 6.5 V mV -0.35 +0.35 -1 +1 50 1200 % mA ICHG = 100 mA (Note 7) 100 75 125 ICHG = 400 mA (Note 7) 400 350 450 ICHG = 600 mA 600 540 660 ICHG = 1100 mA (Note 7) 1100 1040 1160 35 65 mA -9 5 % 2.3 A IPRECHG Pre-charge current 2.2V < VBATT < VFULL_RATE IDCIN Input current limit IDCIN = 435 mA; IBATT = 200 mA IVIN_CHG_MAX Maximum input current in high-current mode VVIN_CHG - VDD 0.8V (Note 7) VFULL_RATE Full-rate qualification threshold VBATT rising, transition from precharge to full-rate charging (2.8V option selected) VRESTART Restart threshold voltage TREG Regulated junction temperature 50 mA 2.8 2.7 2.9 V From VTERM voltage (4.2V, -150 mV options selected) -150 -180 -120 mV 115C option selected (Note 7) 115 C Power OK deglitch time VCHG > VBATT + VOK_CHG 30 ms TPQ_FULL Deglitch time Pre-charge to full-rate charge transition 210 ms TCHG Charge timer Pre-charge mode (default setting) 45 mins CC mode/CV mode (default setting). 5 Hrs TEOC Deglitch time for end-ofcharge transition 210 ms DETECTION AND TIMING (Note 7) TPOK 21 www.national.com LP3925 CHARGER ELECTRICAL CHARACTERISTICS LP3925 Buck Information The LP3925 has integrated three high efficiency step-down DC-DC switching buck converters that deliver a constant voltage from a single cell battery to portable devices. Using voltage mode architecture with synchronous rectification, the buck has the ability to deliver up to 800 mA depending on the input voltage and output voltage, ambient temperature, and the inductor chosen. There are two modes of operation depending on the current required - PWM (Pulse Width Modulation), ECO (ECOnomy) mode. The device operates in PWM mode at load currents of approximately 50 mA (typ.) or higher. Lighter output current loads cause the device to automatically switch into ECO mode for reduced current consumption and a longer battery life. 2 buck regulators are capable of DVS control. Additional features include soft-start, under voltage protection, current overload protection, and thermal shutdown protection. Only three external power components are required for implementation. 30120407 FIGURE 10. Typical PWM Operation INTERNAL SYNCHRONOUS RECTIFICATION While in PWM mode, the buck uses an internal NFET as a synchronous rectifier to reduce rectifier forward voltage drop and associated power loss. Synchronous rectification provides a significant improvement in efficiency whenever the output voltage is relatively low compared to the voltage drop across an ordinary rectifier diode. BUCK CIRCUIT OPERATION The switching buck converter operates as follows. During the first portion of each switching cycle, the control block in the LP3925 turns on the internal PFET switch. This allows current to flow from the input through the inductor to the output filter capacitor and load. The inductor limits the current to a ramp with a slope of (VIN-VOUT)/L, by storing energy in a magnetic field. During the second portion of each cycle, the controller turns the PFET switch off, blocking current flow from the input, and then turns the NFET synchronous rectifier on. The inductor draws current from ground through the NFET to the output filter capacitor and load, which ramps the inductor current down with a slope of -VOUT/L. The output filter stores charge when the inductor current is high, and releases it when low, smoothing the voltage across the load. The output voltage is regulated by modulating the PFET switch on time to control the average current sent to the load. The effect is identical to sending a duty-cycle modulated rectangular wave formed by the switch and synchronous rectifier at the SW pin to a low-pass filter formed by the inductor and output filter capacitor. The output voltage is equal to the average voltage at the SW pin. CURRENT LIMITING A current limit feature allows to protect itself and external components during overload conditions. PWM mode implements current limit using an internal comparator that trips at 1100 mA (typ.). If the output is shorted to ground and output voltage becomes lower than 0.3V (typ.), the device enters a timed current limit mode where the switching frequency will be one fourth, and NFET synchronous rectifier is disabled, thereby preventing excess current and thermal runaway. ECO MODE OPERATION The buck switches from ECO state to PWM state based on output load current. At light loads (less than 50mA), the converter enters ECO mode. In this mode the part operates with low Iq. During ECO operation, the converter positions the output voltage slightly higher (+30mV typ.) than the nominal output voltage in PWM operation. The more complete understanding of an ECO mode operation can be derived from diagram in Figure 11. PWM OPERATION During PWM operation the converter operates as a voltagemode controller with input voltage feed forward. This allows the converter to achieve excellent load and line regulation. The DC gain of the power stage is proportional to the input voltage. To eliminate this dependence, feed forward inversely proportional to the input voltage is introduced. While in PWM mode, the output voltage is regulated by switching at a constant frequency and then modulating the energy per cycle to control power to the load. At the beginning of each clock cycle the PFET switch is turned on and the inductor current ramps up until the comparator trips and the control logic turns off the switch. The current limit comparator can also turn off the switch in case the current limit of the PFET is exceeded. Then the NFET switch is turned on and the inductor current ramps down. The next cycle is initiated by the clock turning off the NFET and turning on the PFET. www.national.com 30120459 FIGURE 11. Typical ECO Operation Power FETs are controlled by "SW Control" which is a combination of `comp' and `pwm' signals, dependent on `PWM threshold' level. "ECO Comparator" is a simple comparator with hysteresis. "Err Amp" and "PWM" are error amplifier with a ramp generator. `PWM threshold' is current sensing at PFET, that lets control logic know which input has to be used. 22 30120457 FIGURE 14. Typical Ripple in ECO Mode BUCK OUTPUT VOLTAGE SELECTION The selection of the bucks' output voltages can be done by writing a specific code into the control registers (addr. 0x10 ... 0x18). The required voltage can be calculated from the following equation: 30120409 FIGURE 12. Buck's Switches Controlling Diagram where COUT = 10 F, ripple V = 50 mV and PFET open time = 350 ns). Where Y* denotes a number, which corresponds to the DVS control code. If DVS is not in use, then VOUT0 is used. 1-bit DVS uses VOUT0 and VOUT1 and 2-bit DVS uses VOUTs 0 to 3. 30120458 FIGURE 13. Typical ECO Operation 23 www.national.com LP3925 The output voltage ripple is slightly higher in ECO mode (30 mV peak-peak ripple typ.) In low load condition `comp' is used and in high load condition `pwm' is used. Once Vout voltage level gets too small, then in low load condition (ECO mode) the "ECO Comparator" triggers and "SW Control" opens PFET (wide pulse at SW pin; see Figure 2). The wideness of that pulse is determined by "ECO comparator" which has a built in hysteresis. Normal in ECO mode after that wide pulse has passed no action should be taken, until next "ECO Comparator" triggering. If some other condition (PWM threshold/Current limit) is fulfilled, then buck enters PWM mode. If `peak current limit' which is a current sensing signal for PFET's switch peak currents triggers, then buck enters PWM mode from the next clock pulse. Peak current sensing is reset at the beginning of every clock pulse. Once in PWM mode, buck will stay there at least 32 clock pulses and if `PWM threshold' indicates that buck should be operating in ECO mode, it will return into ECO mode. This is what actually happens on Figure 2 during wide ECO mode pulse. (The reason behind that is in high peak current during the time PFET is opened. Rough example: LP3925 For example if use the combination L = 0.47 H (DCR = 50 m) and COUT = 30 F (ESR = 10 m), when VIN = 3V and VOUT = 1.8V with load current of 600 mA, the theoretical peak to peak current ripple should be: EXTERNAL COMPONENT SELECTION Default values for external components of LP3925 bucks are input and output capacitances CIN = COUT = 4.7 F and inductor L=1H whit the lowest possible DCR (less than 50 m). Below is the table with the selection of suitable inductors for the application. With the carefull selection of the output components the performance of the buck will not degrade in stability, ripple, load regulation and transient aspects. The inductor current (IL) and output voltage (VOUT) ripples are directly dependent on the external components. Current ripple is mainly dependent on the inductance L while the RMS peak-to-peak voltage ripple should be in the region of: DVS CONTROL DVS allows a buck regulator to step between pre-programmed voltage values, using multifunctional pins as selectors. DVS is supported for Buck1 and Buck2. They can have up to 4 pre-programmed values, which are set in registers BUCKn VOUTn. Multifunctional pins can be set as single DVS selectors (1 selecting signal) or dual DVS selectors (2 selecting signals). DVS-controlling pins must be set as Buck1 DVS (code 0101) or Buck2 DVS (code 0110) pins in their control registers (named GPIOnn). Any multifunctional pin can be used as a single DVS signal. The signal selects between VOUT0 (input low) and VOUT1 (input high). Dual DVS signals can only be predetermined pairs, the function description can be seen in the table below. where fSW is the buck's switching frequency and RPdson is the drain to source resistance of the PMOS power switch. Voltage ripple on the other hand has 2 main components. One dependent on output capacitance: The other is due to capacitor's ESR The resulting RMS ripple is Dual DVS Control Table for Bucks 1 and 2 www.national.com OSC_32KHZ RSENSE SIM_RST_IN SIM_CLK _IN SIM_DATA SIM_RST SIM_CLK SIM_IO TCXO1_I TCXO1_O TCXO2_I TCXO2_O OE_N DATA/VP SE0/VM RCV BUCK1,2 VOUT SPND INP1 INP2 SINK1 SINK2 SINK3 0 0 VOUT0 0 1 VOUT1 1 0 VOUT2 1 1 VOUT3 24 LP3925 BUCK TYPICAL PERFORMANCE PLOTS Efficiency (VIN = 3.0V, VOUT = 1.2V) Efficiency (VIN = 3.6V, VOUT = 1.2V) 30120451 30120453 Efficiency (VIN = 4.2V, VOUT = 1.2V) Efficiency (VIN = 3.0V, VOUT = 1.76V) 30120455 30120452 Efficiency (VIN = 3.6V, VOUT = 1.76V) Efficiency (VIN = 4.2V, VOUT = 1.76V) 30120454 30120456 25 www.national.com LP3925 Buck1 Fast Rise (1s) Buck2 Fast Rise (1s) 30120447 30120446 Buck3 Fast Rise (1s) Buck1 Slow Rise (5s) 30120445 30120448 Buck2 Slow Rise (5s) Buck1 Slow Rise (5s) 30120449 www.national.com 30120450 26 Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -25C to +85C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol VFB Parameter Feedback Voltage Condition Typ Limits Units Min Max PWM Mode, No load VOUT = 1.1V to 1.8V -3 3 % PWM Mode, No load VOUT = 0.75V to 1.0V -10 10 mV IQ_ECO ECO mode IQ ECO Mode, FB = VIN No switching, sleep mode 25 RDSON (P) Pin-Pin Resistance for PFET VIN = VGS = 3.6V IOUT = 200 mA 160 250 m RDSON (N) Pin-Pin Resistance for NFET VIN = VGS = 3.6V IOUT = -200 mA 115 180 m ILIM Switch Peak Current Limit Open loop; BuckX = 11 1475 mA tSTARTUP StartUp Time from Shutdown IOUT= 0 VOUT 0 - 97% (Note 7) 65 s FSW Switching Frequency PWM Mode 4 27 A 3.6 4.4 MHz www.national.com LP3925 BUCK ELECTRICAL CHARACTERISTICS LP3925 The innovative design of these general type LDOs reduces the sensitivity to the placement of the output capacitor. These general purpose LDOs do not need the output capacitor to be placed as close to the PMU as is the case for normal LDOs. If a (1F or more) capacitor is attached to a circuit load there is no need to place an output capacitor at the PMU. LDO Information There are altogether 15 LDOs in LP3925 grouped as: * General-type "PERFECT" LDOs; * WILO-type LDOs; * MICRO-PWR LDO; and * USB LDO. All LDOs can be programmed through serial interface for different output voltage values which are summarized in the "Control Register Bit Description" tables. At the PMU power on, LDOs start up according to the selected startup sequence and the default voltages. See section Power-on and Power-On Sequences for details. For stability all LDOs need to have external capacitors COUT connected to the output with recommended value of 1F . It is important to select the type of capacitor which capacitance will in no case (voltage, temperature, etc) be outside of limits specified in the LDO Electrical Characteristics. The description of different LDO types follow, except for the RTC description in the following section. WILO-TYPE LDOs Wide Input Low Output (WILO) LDOsThe WILO-type LDO is optimized for wide range supply and low output voltage. It has good dynamic performance to supply different fast changing (digital) loads. For proper operation, an input voltage of more than 2V is necessary. Hence, voltage drop on pass transistor (dropout voltage) will always exceed 0.45V and is independent of output current (in specified current range). For fast discharge of the output capacitors in shut down, an internal 300 pull-down resistor to ground can be set via program control MICRO-PWR LDO This LDO is primarily used for internal supply purposes and fixed to 1.8V, but may deliver up to 30 mA of current also externally. This LDO is ON even in Standby mode (with total PMU current consumption about 2A) and user may use it to supply some backup/always on system(s). GENERAL-TYPE "PERFECT" LDOs The general "PERFECT" LDOs are optimized to supply both analog and digital loads having ULTRA LOW NOISE (10 VRMS for IOUT > 5mA) and excellent PSRR (75 dB at 10 kHz) performance. They can be programmed through the serial interface for different output voltage values. For fast discharging of the output capacitors in shutdown, an internal 300 pull-down resistor to ground can be set via program control. In sleep mode quiescent current is lowered to 5A for energy saving; in this mode these LDOs should not be loaded by more than 3-5mA of output current. USB LDO USB LDO is a high voltage LDO that uses VIN_CHG as a supply. It is used as a supply for D+ and D- buses as well as the VTRM output. It has a 28V over voltage protection capability. Regulator provides 45 dB PSRR at 10 kHz on entire voltage selection range except 4.85V option. Here it is 30 dB and is due to small distance to supply. GENERAL LDO ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol VOUT IMAX ISC Parameter Output Voltage Accuracy Output Current Limit Output Current in sleep mode IQ Quiescent current in sleep mode www.national.com IOUT = 1mA, VOUT = 2.0V Output Current Rating ISLEEP VDO Conditions Dropout Voltage LDO# Typ. 1...10 Limits Min Units Max -2 2 -3 3 4,8 80 1..3, 5..7, 9, 10 300 % mA VOUT +0.5V VIN 4.5V (Note 7) 4,8 300 80 mA VOUT +0.5V VIN 4.5V (Note 7) 1..3, 5..7, 9, 10 650 300 mA VOUT +0.5V VIN 4.5V 1..10 3 5 VOUT = 3V; IOUT = IMAX (Note 8) 28 mA A 4, 8 60 150 1..3, 4..7, 9, 10 100 200 mV Parameter Line Regulation Conditions VOUT +0.5V VIN 4.5V IOUT = IMAX VOUT 1..10 3 mV mV Max 4, 8 0.5 3.5 1...10 15 VRMS 1..10 70 dB 1...10 45 50 s 1...10 -30 35 mV V eN Output Noise Voltage 10 Hz f 100 kHz COUT = 1F (Note 7) PSRR Power Supply Ripple Rejection f = 10 kHz, COUT = 1F Ratio IOUT = 20 mA (Note 7) tSTART-UP Start-Up Time from Shut-down VLOADTRANS Load transient overshoot VLINETRANS Line transient, peak-to-peak VIN = 3.6 4.2 3.6; tr = tf = 30 s IOUT = 50 mA (Note 7) 1...10 90 VTRANSIENT Start-Up Transient Overshoot COUT = 1F, IOUT = IMAX (Note 7) 1...10 1 COUT External output capacitance for stability 1...10 1 IOUT= 0 VOUT 0 - 97% (Note 7) IOUT = 0 200 mA (Note 7) Min 1..3, 5..7, 9, 10 1mA IOUT IMAX IOUT = 0 200 mA Units Typ. Load Regulation VOUT 0 - 90% Limits LDO# 0.6 30 mV 20 F WILO-TYPE LDO ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6, Note 10) Symbol Parameter Conditions LDO# Typ. VOUT Output Voltage Accuracy IOUT = 1mA, VOUT = 2.0V 11...13 ISC Output Current Limit VOUT = 0V 11...13 IMAX Output Current Rating VDO Dropout Voltage VOUT = 3V; IOUT = IMAX (Note 8) 11...13 150 Line Regulation VOUT +0.5V VIN 4.5V IOUT = IMAX 11...13 2.5 Load Regulation 1mA IOUT IMAX 11...13 3 Quiescent current in normal mode (Note 7) IQsleep Quiescent current in sleep mode (Note 7) eN Output Noise Voltage 10 Hz f 100 kHz COUT = 1F, IOUT = 20 mA VOUT = 1.8V (Note 7) PSRR tSTARTUP Startup Time from Shutdown VOUT IQnormal 600 Limits Min Units Max -2 2 -3 3 % mA 300 300 mA 250 mV mV 17 11...13 A 4 11...13 85 VRMS Power Supply Ripple Rejection f = 10 kHz, COUT = 1F Ratio IOUT = 20 mA (Note 7) 11...13 60 dB COUT = 1F, IOUT = IMAX 11...13 35 s 29 www.national.com LP3925 Symbol LP3925 Symbol Parameter Conditions VTRANSIENT Startup Transient Overshoot COUT External output capacitance for stability COUT = 1F, IOUT = IMAX LDO# Typ. Limits Min Max 11...13 11...13 1.0 Units 0.5 30 mV 20 F MICRO-PWR LDO ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol VOUT Parameter Conditions Output Voltage Accuracy IOUT = 1mA, VOUT = 1.80V IMAX ISC Typ. Limits Min Units Max 1.8 V Maximum Output Current VOUT = 1.8V 30 mA Output Current Limit VOUT = 0V 220 mA Line Regulation VOUT +0.5V VIN 4.5V IOUT = IMAX 2 Load Regulation 1mA IOUT IMAX 1 PSRR Power Supply Ripple Rejection Ratio f = 10 kHz, COUT = 1F IOUT = 20 mA (Note 7) 45 dB tSTARTUP Startup Time from Shutdown COUT = 1F, IOUT = IMAX (Note 7) 200 s VTRANSIENT Startup Transient Overshoot COUT = 1F, IOUT = IMAX (Note 7) COUT External output capacitance for stability VOUT 1.0 mV 0.6 75 mV 20 F USB LDO ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VVIN_CHG = 5.0V. (Note 6) Symbol Parameter Conditions Typ. Limits Units Min Max 3.15 3.45 VOUT Output Voltage Accuracy IOUT = 1mA, VOUT = 3.30V IMAX Maximum Output Current VOUT = 3.30V 50 mA ISC Output Current Limit VOUT = 0V 300 mA Dropout Voltage IOUT = IMAX USB LDO VOUT = 4.85V (Note 8) 330 mV Line Regulation VOUT +0.5V VIN_CHG 6.5V IOUT = 10 mA, VOUT = 4.85V 5 Load Regulation 1mA IOUT IMAX VOUT = 3.3V 6 PSRR Power Supply Ripple Rejection Ratio f = 10 kHz, COUT = 1F IOUT = 20 mA (Note 7) 45 dB tSTARTUP Startup Time from Shutdown COUT = 1F, IOUT = IMAX (Note 7) 15 s VTRANSIENT Startup Transient Overshoot COUT = 1F, IOUT = IMAX 250 mV COUT External output capacitance for stability VDO VOUT www.national.com mV 1.0 30 V 0.6 20 F USB TRANSCEIVER USB transceiver complies with USB 2.0 specification for fullspeed (12Mb/s) device and low-speed (1.5Mb/s) device operation. The transceiver also supports USB Charger Detection by "Battery Charging Specification Revision 1.0 Mar 8, 2007". The transceiver includes internal 1.5 k pull-up resistor and it is supplied from USB LDO. 30120420 FIGURE 15. USB Transceiver Block Diagram USB Transceiver enable is controlled by register 0x41 (USB XCVR CONTROL bits) and 0x36 (bit ALLOW USB XCVR IN SLEEP). If AUTOMATIC USB DETECTION bit is set 1 then in any circumstances the USB transceiver stays disabled until USB Charger Detection is completed. USB Speed is determined by bit USB SPEED in register 0x4D: USB SPEED USB CHARGER DETECTION USB Charger Detection works according to "Battery Charging Specification Revision 1.0 Mar 8, 2007" published by USB-IF. To enable USB Charger detection: (1) bit AUTOMATIC USB DETECTION in register 0x4D should be set 1; and (2) Charger should be enabled. After VIN_CHG voltage was detected to be high enough to start charging USB Charger Detection waits 900 ms and then checks D+ and D- for 100 ms. The detection result can be read form register 0x8D: 1 - Full Speed (12 Mb/s) 0 - Low Speed (1.5 Mb/s) 31 www.national.com LP3925 USB transceiver can be configured to 3-pin, 4-pin or 5-pin interface. If "USB transceiver not used" is configured, then USB transceiver is disabled in all circumstances, D+ and D- pins are HiZ and also 1.5 k pull-up resistor is disconnected. USB LDO has separate enable control and can be used also if "USB transceiver is not used". USB Transceiver LP3925 USB DETECTION DONE 1- USB Charger Detection completed 0 - USB Charger Detection is in progress or charger is disabled or there is no enough voltage on VIN_CHG. USB DETECTION RESULT 1 - USB Charger detected 0 - USB host detected If AUTOMATIC USB DETECTION is enabled (bit is set 1) then USB Transceiver stays disabled in all circumstances until USB Charger detection is completed. USB Charger Detection block gets supply from VTRM. To have detection result correct then USB_LDO should be enabled 30120421 FIGURE 16. USB Transceiver Configured to 3-Pin Interface INTERFACE PINS DATA USB Interface data input/output SE0 USB interface single ended 0 input/output OE_N USB Output Enable, active low TRUTH TABLE FOR 3-PIN INTERFACE Transmitting OE_N=0 inputs Receiving OE_N=1 outputs inputs outputs DATA/VP* SE0/VM* D+ D- D+ D- DATA/VP* SE0/VM* 0 0 0 1 0 0 previous state 1 0 1 0 0 0 1 0 0 1 0 1 0 1 0 1 0 1 1 0 0 1 1 undefined 0 www.national.com 32 LP3925 30120422 FIGURE 17. USB Transceiver Configured to 4-Pin Interface INTERFACE PINS VM USB interface minus input/output VP USB interface plus input/output RCV Receiver data - single ended output from USB differential lines. OE_N USB Output Enable, active low. Controlling the Transceiver OE_N VP VM FUNCTION 0 Input D+ = VP Input D- = VM Transmitting 1 Output D+ = VP Output D- = VM Receiving 33 www.national.com LP3925 30120423 FIGURE 18. USB Transceiver Configured to 5-Pin Interface INTERFACE PINS VM USB interface minus input/output VP USB interface plus input/output RCV Receiver data - single ended output from USB differential lines. OE_N USB Output Enable, active low. SPND USB suspend mode control input. A logical high will power down the differential receiver; VM and VP will remain active with reduced power consumption. CONTROLLING THE TRANSCEIVER IN 5-PIN CONFIGURATION SPND OE_N 0 0 Driving Active Input Normal Transmitting 0 1 Receiving Active Output Normal Receiving 1 0 Driving USB_RCV_OFF in 0x6B Input Low-Power Transmitting 1 1 Receiving USB_RCV_OFF in 0x6B Output Low-Power Receiving www.national.com D+/D- RCV VP/VM 34 Function Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VVIN_CHG = 5V. (Note 6) Symbol Parameter VDAT_SRC Data Source Voltage VDAT_REF Data Detect Voltage IDAT_SINK Data Sink Current Conditions Load Current = 200 A 0.15V < VD- < 3.6V Typ. Limits Units Min Max 0.6 0.5 0.7 0.325 0.25 0.4 100 50 150 V A USB TRANSCEIVER ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V, VTRM = 3.3V. (Note 6) Symbol Parameter Conditions VBUS VIN_CHG Supply Voltage VIN_CHG pin works as USB VBUS pin IBUS VIN_CHG pin quiescent current Low-speed VIN_CHG pin works as USB VBUS pin USB Transmitter Receiving USB_LDO enabled, charger OFF Typ. Limits Units Min Max 4.2 5.5 V 2.5 mA 10 A 1.1 Transceiver DC Characteristics ILO 0V < V < VTRM Hi-Z State data line leakage D+ if Low Speed; D- if High Speed, OE_N = 1. -10 VDI Differential input sensitivity |(D+)-(D-)|, VIN = 0.8V - 2.5V 200 VCM Differential common-mode range 0.8 Includes VDI Range (Note 7) Single-ended receiver threshold high VSE mV 2.5 V 2.0 V Single-ended receiver threshold low 0.8 Receiver Hysteresis 100 mV VOL Static Output Low OE_N = 0, RLOAD = 1.5 k to 3.6V VOH Static Output High OE_N = 0, RLOAD = 15 k to GND 2.8 3.6 VTRM Termination voltage IOUT = 0, USB_LDO programmed to 3.3V 3.15 3.45 RTRM Pullup Resistance CIN Transceiver Capacitance Pin to GND (Note 7) ZDRV Drive Output Resistance D+, D- steady-state drive, IOUT = 15 mA from regulator (Note 7) 0.3 1.5 V k 20 pF 28 44 Low-Speed Driver Characteristics tR Transition Rise Time CLOAD = 50-600 pF (Note 7) 75 300 tF Transition Fall Time CLOAD = 50-600 pF (Note 7) 75 300 tR/tF Rise/Fall Time Matching R/tF 80 125 (Note 7) ns % Full-Speed Driver Characteristics tR Transition Rise Time CLOAD = 50 pF (Note 7) 4 20 tF Transition Fall Time CLOAD = 50 pF (Note 7) 4 20 tR/tF Rise/Fall Time Matching R/tF 90 110 (Note 7) 35 ns % www.national.com LP3925 USB CHARGER DETECTION ELECTRICAL CHARACTERISTICS LP3925 If TCXO buffers are enabled, then they need some time to reach a working point. During this time the output signal can have an undesirable shape. To avoid unwanted signals, "TCXO in wait" control signals allow to set the time delay before enabling TCXO buffer output. "TCXO out strength" signals modify buffer output drive strength. Possible values of "TCXO in wait" and "TCXO out strength" are stated in the GPIO section. Buffers are supplied from LDO1. TCXO Buffers The TCXO Buffer amplifies the 20 MHz sine wave from an external TCXO and shapes it into a buffered square wave clock signal with controlled rise and fall times. The buffer input connected to an internal decoupling capacitor. The output clock signal has a default slew rate of 325 V/ s with an external load capacitance of 12.5 pF. The slew rate can be adjusted by changing the two-bit control data in the control register. This may be necessary if the actual load capacitance is considerably higher or the clock slew rate needs to be slower for EMC reasons. TCXO BUFFER ELECTRICAL CHARACTERISTICS Unless otherwise noted VBATT = VDD = 3.6V, CBYP_CHG = 1F, CFB_CHG = 10 F. Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter Conditions Typ. VIN Input Voltage Level (Note 7) VOH High-Level Output Voltage DC at 1A 2.5 VOL Low-Level Output Voltage DC at 1A 0.1 TP Propagation Delay CL = 13 pF (Note 7) 12 TTT Output Transition Time CL = 13 pF (10% and 90% level) (Note 7) 7 VSR Output Slew Rate CL = 13 pF (Note 7) 325 CIN Input Capacitance (Note 7) Units Max mVP-P 750 2 For warm-up time and driving strength refer to multifunctional pins section. www.national.com Limits Min 36 2.4 0.2 V ns 200 450 V/s 10 pF Backup battery charger (BBC) is intended for charging an external coin battery. Its output is connected to VCOIN-pin. It consists of Voltage Limited Current Source with 1k output resistor. By default it is always on. It is possible to turn backup battery charger off via registers. VCOIN - voltage limit and ICOIN - current source values are also programmable via registers (the possible values are stated in Backup battery charger selection table). BBC has a reverse current protection. VCOIN-pin voltage can be measured by an internal ADC. 32.768 kHz CRYSTAL OSCILLATOR There are two options for implementing the 32.768 kHz oscillator: 1. 1. An external crystal that is connected between XIN and XOUT. The external crystal ESR must not exceed 100 k; if this value is exceeded the circuit may never start oscillating. 2. 2. An external oscillator module could be used by connecting the module output directly into XIN. When using an external oscillator module, the XOUT pin should be unconnected. Pins XIN and XOUT are not able to drive external load. Oscillator output is buffered to pin OSC_32KHZx Note. Oscillator is powered by LDO1, thus before it is up, the oscillator will not start. 30120419 FIGURE 19. BBC IU Characteristics BACKUP BATTERY CHARGER ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter Conditions Typ. Limits Units Min Max VCOIN Voltage Limit ILOAD = 1A; VCOIN programmed to 3.00V -3 +3 % ICOIN Charging Current VCOIN pin shorted to GND ICOIN programmed to 200 A -20 +20 % RVCOIN Internal Series Resistor 0.5 1.6 k ILEAK Reverse leakage current VRTC-pin current = 0 Charger Ground Current ILOAD = 0. 2.5 Load Regulation ILOAD = 0. 0.5 IGND 1.0 37 10 A www.national.com LP3925 MOMENTARY POWER LOSS When power is removed from the LP3925 PMU and MPL function is enabled (register 0x81) then Momentary Power Loss (MPL) timer starts as unexpected power down has occurred. This timer is set to the maximum duration allowed for a momentary power loss (register 0x81). If power is restored before the timer expires, then MPL block informs LP3925 control logic about MPL-event. The MPL circuit is powered from VCOIN-pin. MPL timer uses 32.786 kHz RTC crystal oscillator for time base. Host processor needs to enable the MPL function every time the device is powered up. Backup Battery Charger LP3925 Real Time Clock * The Real Time Clock (RTC) block is used for time tracking in any chip condition. It uses 32 kHz crystal oscillator for accurate timekeeping and is supplied either from system supply in normal condition or from coin battery when the PMU has no main power. The RTC gets power from VCOIN, with min guaranteed operation above 1.9V. This RTC has following features: * * * Accurate time counting with fine-grained correction for long-term accuracies; Calendar for years 2000 - 2099 with leap year compensation and automatic weekday calculation; Two highly customizable alarms; and Data in software-friendly binary format. 30120444 FIGURE 20. RTC Functional Block Diagram Calendar and alarm data is presented in following format: Time Unit Register Data Represented Values Seconds 000000 - 111011 0 - 59 Minutes 000000 - 111011 0 - 59 Hours 00000 - 10111 0 - 23 Day of Month 00001 - 11111 1 - 31 Month 0001 - 1100 January - December Year 0000000 - 1100011 2000 - 2099 Weekday 0000001 - 1000000 (1-hot code) Monday - Sunday RTC calendar and alarm registers are user-writable, except for calendar weekday registers, which are calculated automatically and are read-only. All RTC registers are in RTC power domain. The registers are zeroed, if RTC is powered up. As long as RTC is supplied, the alarm registers will hold the written data and the calendar will keep track of time. Writing data to a calendar register will initiate a calendar write sequence, which will last 3ms. During this time the register's data should not be read, because it may not be accurate. Alarms allow creating periodical or one-time events. The result of an alarm event depends on the PMU state. If PMU is in standby, then alarm can cause PMU to start up. If PMU is in working mode, then alarm can create an interrupt. www.national.com Alarm event happens if the alarm is activated (ALARM ACTIVATED bit is 1) and current RTC time matches the time in all alarm configuration registers. To exclude a time unit value from matching check, write the unit's IGNORE bit to 1. If alarm's weekday is not important or not known, then all weekday bits should be set to 1. Interrupt or PMU startup is triggered at the start of an alarm event. The RTC also has a time counting correction register. This can slightly change time counting speed to compensate for oscillator inaccuracies. Correction events happen 7 times in an hour. The maximum correction range is 241 ppm (corresponds to code 127) and one step size is approximately 1.9 ppm. 38 LP3925 includes a SIM/RUIM card interface level-shifter function. This can be used, if the processor I/O voltage and SIM card I/O voltage have different values. The interface includes pins for 3 signals: reset, clock and data. Reset and clock are unidirectional control signals, going from the processor to the SIM card. Data signal is bidirectional. USIM LEVEL TRANSLATOR ELECTRICAL CHARACTERISTICS Unless otherwise noted, CLDOx = CVIN_CHG+CVBUS+CVTRM = 1F. Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter VILS Input low threshold VIHS Input high threshold VOLS Output Low Level VOHS Output High Level RINPU SIM_IO pullup resistor VIL_SIM_IO Input Low VIH_SIM_IO Input High VOL_SIM_IO Output Low Level when SIM_DATA=GND VOH_SIM_IO Output High Level RSPU SIM_DATA pullup resistor VIL_SIM_DATA Input Low Conditions Typ Input High VOL_SIM_DATA Output Low Level when SIM_IO=GND VOH_SIM_DATA Output High Level Max 0.25* VLDO1 RST_IN, CLK_IN Logic Inputs, LDO1 supply selected 0.75* VLDO1 0.25* VLDO8 SIM_RST, SIM_CLK Logic Outputs VIH_SIM_DATA Limits Min 0.75* VLDO8 10 Units V V K 0.3 VDD-0.6V SIM_IO 0.25* VLDO8 V 0.75* VLDO8 20 13 K 0.3 0.75* VLDO1 SIM_DATA, LDO1 supply selected 0.25* VLDO1 V 0.75* VLDO1 Timing Clock Frequency (Note 7) 20 39 5 MHz www.national.com LP3925 The SIM card side of the level shifter is always supplied by LDO8. The processor side supply is user-selectable between Buck2, LDO1 and LDO11. If the level shifter is enabled, then the supplies on both sides must be 1.5V or higher to ensure proper operation. USIM Interface LP3925 30120434 FIGURE 21. SIM Interface Level Shifters available between 400 mV and 2400 mV, the values can be found in the multifunction pins section. Comparator state is available from registers as a read-only bit, or from multifunctional pins as a direct data output. It is also possible to generate an interrupt every time the comparator state changes. Comparators Two general purpose comparators are available, which can be used for detecting the plugging of external accessories or other events. Voltage comparators are available on multifunctional pins INP1 and INP2. 8 comparison thresholds are COMPARATOR ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter Conditions Typ. VTH Input Threshold Voltage Default Setting 0.6 VTH2 Input threshold voltage 2 Default Setting 1 IIL Input leakage current INP1, INP2 0 VINPUT VVIN1. Units Max V -1 1 A allows starting the conversion, source selection and output format selection. Setting the ADC CONV START bit in the control register starts a new A/D conversion. Setting ADC_FORMAT bit to 1 allows throwing out the MSB and shifting the result 1 bit left. This can be used if result's MSB is known, to get more data with one register read. ADC LP3925 is equipped with a 12-bit ADC that has 8 inputs for measuring charging current, discharge current, battery voltage (measuring at BATT pin), backup battery voltage, charger input voltage, VDD, temperature and external signal through GPIO. The inputs are scaled linearly to adapt the voltage/current range of the source to the input voltage range of the A/D core. The ADC is clocked by the internal 4MHz system clock. The conversion result is available in the registers 0x88 and 0x89 in 3ms after the setting of the ADC CONV START bit in the 0x87 Register. The ADC will automatically enter power save mode if conversions are not performed. BATTERY DISCHARGE CURRENT MEASUREMENT The discharge current is measured indirectly by measuring the voltage drop produced by discharge current on the Rsense. The calculation of the current value is done by equation below: A/D CONVERTER DATA AND CONTROL REGISTERS Two read only registers 0x88 and 0x89 provide access to the a/d conversion result. 8 most significant bits of the data can be accessed in one read cycle. The Read/Write 0x87 register www.national.com Limits Min 40 OTHER ITEM CURRENT VOLTAGE MEASUREMENT JUNCTION TEMPERATURE MEASUREMENT Temperature measurement is performed in the rage of +390 C...-275C which means that the following equation is valid for calculating the chip's junction temperature: For example: If ADC input SEL is set as 0011, it will measure the BATT voltage. Full_Scale_Value = 4.80V; so VBATT = code (dec) * 4.8/4095. 30120417 FIGURE 22. LP3925 ADC Temperature Range ADC ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter Conditions Resolution Typ. Limits Min Max 12 bits INL Integral Nonlinearity (Note 7) -4 +4 DNL Differential Nonlinearity No missing code (Note 7) -2 +2 Conversion Time (Note 7) 3 41 Units LSB ms www.national.com LP3925 The value of the appropriate VSNS (so that the maximum code would correspond to 1.2A) can be chosen in reg.0x19. That is if RSENSE = 100 m, the VSNS should equal 120 mV. LP3925 Reference Output Reference Output Reference output voltage is used by the external blocks (plug-in microphone, ADCs, etc). This voltage is achieved by the reference buffer and is supplied to the REF_OUT bump. Reference buffer has a load capability of 1mA and when not used can be disabled while the output is pulled by an internal resistor to the ground. A presented diagram shows a typical application of REF_OUT signal for battery temperature measurement purpose, using an internal battery thermistor. 30120436 FIGURE 23. Typical REF_OUT Battery Temperature Measurement Application Diagram REFERENCE BUFFER ELECTRICAL CHARACTERISTICS Typical values and limits appearing in normal type apply for TJ = 25C. Limits appearing in boldface type apply over the entire junction temperature range for operation, TJ = -40C to +125C. Unless otherwise specified, the following applies for VBATT = 3.6V. (Note 6) Symbol Parameter VREF Reference voltage accuracy ILOAD Load Current RPULL_DOWN Integral Nonlinearity Conditions Typ. ILOAD = 0mA 0.3 ILOAD = 1mA 1 Limits Min Max % -1 400 Units +1 mA k UVLO Operation Current Sinks UVLO measures system voltage on pin VDD and compares it to selected voltages. The function uses 2 comparators, which are configured in register address 0x85 (possible values are stated in the table below). These comparators are combined into UVLO_N state, which can affect startup, cause shutdown or generate interrupt. The state is readable in register address 0x8E bit 2. UVLO_N state can change on following conditions: * If system voltage is lower than UVLO LEVEL1 and UVLO LEVEL2, then UVLO_N state is set to '0'. * If system voltage is higher than UVLO LEVEL1 and UVLO LEVEL2, then UVLO_N state is set to '1'. Using different values for levels 1 and 2 provides a window for voltage drops under high load working conditions. UVLO_N state '0' indicates that the voltage is below normal working range, so the system is not allowed to start up. This state can also cause the system to shut down. UVLO_N state '1' indicates that the voltage is in normal working range, so the system is allowed to start up and operate. State transition '1'->'0' causes an UVLO interrupt, which can be sent to IRQ_N output. LP3925 provides 3 current sinks, which can sink current for LEDs, vibration motors or other external functions. Current sinks have selectable DC current value and also PWM control options. SINK1, SINK2 and SINK3 are multifunction pins, so current sink function and DC current value are selectable with respective GPIO control bits (described in the table in Multifunctional pins section). SINK1 has a 250 mA maximum current value, SINK2 and SINK3 provide up to 100 mA. If the pin is configured as a current sink with a certain current, then PWM CODE bits will switch that current on and off, according to the PWM algorithm. The smallest unit in PWM control is a time slot. The length of a time slot is set with ISINK PWM TIME SLOT SIZE bits. Smaller time slot causes faster switching, but increases nonlinearity. 7 time slots form a PWM cycle. Cycle is the current sink on-off switching period, so the main PWM frequency can be calculated as: Fpwm = 1/(7*Ttimeslot). 9 cycles, which is 9*7=63 time slots, form a PWM pattern. ISINK PWM CODE bits select, during how many of these 63 time slots the current sink is active. Code 000000 means that the sink is always off. Code 111111 (63 in decimal) means that the sink is always on. www.national.com 42 LP3925 30120437 FIGURE 24. Current Sinks PWM Control by excessive power dissipation. The temperature monitoring function has two threshold values TSD_H and TSD_L that result in protective actions. When TSD_L +125C is exceeded, then IRQ_N is set to low and "1" is written to TSD_L bit in both STATUS register and in INTERRUPT register. If the temperature exceeds TSD_H +160C, then PMU initiates Shutdown. The POWER UP operation after Thermal Shutdown can be initiated only after the chip has cooled down to the +115C threshold Support Functions REFERENCE LP3925 has internal reference block creating all necessary references and biasing for all blocks. OSCILLATOR There is internal oscillator giving clock to the bucks and to logic control. VVBATT = 3.6V Parameter Typ Min Max Unit Oscillator Frequency 4.0 3.9 4.1 MHz Parameter Typ. TSDH (Note 7) 160 TSDL (Note 7) 125 TSDL Hysteresis (Note 7) 10 Unit C THERMAL SHUTDOWN The Thermal Shutdown (TSD) function monitors the chip temperature to protect the chip from temperature damage caused 43 www.national.com LP3925 Condition to terminate the transaction. Every byte written to the SDA bus must be 8 bits long and is transferred with the most significant bit first. After each byte, an Acknowledge signal must follow. The following sections provide further details of this process. I2C-Compatible Serial Bus Interface INTERFACE BUS OVERVIEW The I2C compatible synchronous serial interface provides access to the programmable functions and registers on the device. This protocol uses a two-wire interface for bi-directional communications between the IC's connected to the bus. The two interface lines are the Serial Data Line (SDA), and the Serial Clock Line (SCL). These lines should be connected to a positive supply, via a pull-up resistor of 1.5 k, and remain HIGH even when the bus is idle. Every device on the bus is assigned a unique address and acts as either a Master or a Slave depending on whether it generates or receives the serial clock (SCL). START AND STOP The Master device on the bus always generates the Start and Stop Conditions (control codes). After a Start Condition is generated, the bus is considered busy and it retains this status until a certain time after a Stop Condition is generated. A high-to-low transition of the data line (SDA) while the clock (SCL) is high indicates a Start Condition. A low-to-high transition of the SDA line while the SCL is high indicates a Stop Condition. DATA TRANSACTIONS One data bit is transferred during each clock pulse. Data is sampled during the high state of the serial clock (SCL). Consequently, throughout the clock's high period, the data should remain stable. Any changes on the SDA line during the high state of the SCL and in the middle of a transaction, aborts the current transaction. New data should be sent during the low SCL state. This protocol permits a single data line to transfer both command/control information and data using the synchronous serial clock. 30120441 FIGURE 26. Start and Stop Conditions In addition to the first Start Condition, a repeated Start Condition can be generated in the middle of a transaction. This allows another device to be accessed, or a register read cycle. ACKNOWLEDGE CYCLE The Acknowledge Cycle consists of two signals: the acknowledge clock pulse the master sends with each byte transferred, and the acknowledge signal sent by the receiving device. The master generates the acknowledge clock pulse on the ninth clock pulse of the byte transfer. The transmitter releases the SDA line (permits it to go high) to allow the receiver to send the acknowledge signal. The receiver must pulldown the SDA line during the acknowledge clock pulse and ensure that SDA remains low during the high period of the clock pulse, thus signaling the correct reception of the last data byte and its readiness to receive the next byte. 30120439 FIGURE 25. Bit Transfer Each data transaction is composed of a Start Condition, a number of byte transfers (set by the software) and a Stop 30120440 FIGURE 27. Bus Acknowledge Cycle www.national.com 44 * * * * * * * Slave device sends acknowledge signal if the slave address is correct. Master sends control register address (8 bits). Slave sends acknowledge signal. Master sends data byte to be written to the addressed register. Slave sends acknowledge signal. If master will send further data bytes the control register address will be incremented by one after acknowledge signal. Write cycle ends when the master creates stop condition. CONTROL REGISTER READ CYCLE * Master device generates a start condition. * Master device sends slave address (7 bits) and the data direction bit (r/w = '0'). * Slave device sends acknowledge signal if the slave address is correct. * Master sends control register address (8 bits). * Slave sends acknowledge signal. * Master device generates repeated start condition. * Master sends the slave address (7 bits) and the data direction bit (r/w = "1"). * Slave sends acknowledge signal if the slave address is correct. * Slave sends data byte from addressed register. * If the master device sends acknowledge signal, the control register address will be incremented by one. Slave device sends data byte from addressed register. * Read cycle ends when the master does not generate acknowledge signal after data byte and generates stop condition. ADDRESSING TRANSFER FORMATS Each device on the bus has a unique slave address. The LP3925 operates as a slave device with the address 7h'xx (binary nnnnnnnn). Before any data is transmitted, the master transmits the address of the slave being addressed. The slave device should send an acknowledge signal on the SDA line, once it recognizes its address. The slave address is the first seven bits after a Start Condition. The direction of the data transfer (R/W) depends on the bit sent after the slave address -- the eighth bit. When the slave address is sent, each device in the system compares this slave address with its own. If there is a match, the device considers itself addressed and sends an acknowledge signal. Depending upon the state of the R/W bit (1:read, 0:write), the device acts as a transmitter or a receiver. CONTROL REGISTER WRITE CYCLE * Master device generates start condition. * Master device sends slave address (7 bits) and the data direction bit (r/w = '0'). Address Mode Data Read <Start Condition> <Slave Address><r/w = `0'>[Ack] <Register Addr.>[Ack] <Repeated Start Condition> <Slave Address><r/w = `1'>[Ack] [Register Data]<Ack or NAck> ... additional reads from subsequent register address possible <Stop Condition> Data Write <Start Condition> <Slave Address><r/w = `0'>[Ack] <Register Addr.>[Ack] <Register Data>[Ack] ... additional writes to subsequent register address possible <Stop Condition> < > Data from master [ ] Data from slave 45 www.national.com LP3925 "ACKNOWLEDGE AFTER EVERY BYTE" RULE The master generates an acknowledge clock pulse after each byte transfer. The receiver sends an acknowledge signal after every byte received. There is one exception to the "acknowledge after every byte" rule. When the master is the receiver, it must indicate to the transmitter an end of data by not-acknowledging ("negative acknowledge") the last byte clocked out of the slave. This "negative acknowledge" still includes the acknowledge clock pulse (generated by the master), but the SDA line is not pulled down. LP3925 REGISTER READ AND WRITE DETAIL 30120442 FIGURE 28. Register Write Format 30120443 FIGURE 29. Register Read Format For more detailed control register information, or to order samples, please contact your local National Semiconductor sales office or visit http://www.national.com/support/dir.html www.national.com 46 LP3925 47 www.national.com LP3925 Physical Dimensions inches (millimeters) unless otherwise noted Micro SMDxt 81 Package NS Package Number RMD81AAA X1 = 3.615mm 0.030mm X2 = 3.615mm 0.030mm X3 = 0.650mm 0.075mm www.national.com 48 LP3925 Notes 49 www.national.com LP3925 High Performance Power Management Unit for Handset Applications Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: www.national.com Products Design Support Amplifiers www.national.com/amplifiers WEBENCH(R) Tools www.national.com/webench Audio www.national.com/audio App Notes www.national.com/appnotes Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns Data Converters www.national.com/adc Samples www.national.com/samples Interface www.national.com/interface Eval Boards www.national.com/evalboards LVDS www.national.com/lvds Packaging www.national.com/packaging Power Management www.national.com/power Green Compliance www.national.com/quality/green Switching Regulators www.national.com/switchers Distributors www.national.com/contacts LDOs www.national.com/ldo Quality and Reliability www.national.com/quality LED Lighting www.national.com/led Feedback/Support www.national.com/feedback Voltage References www.national.com/vref Design Made Easy www.national.com/easy www.national.com/powerwise Applications & Markets www.national.com/solutions Mil/Aero www.national.com/milaero PowerWise(R) Solutions Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors SolarMagicTM www.national.com/solarmagic PLL/VCO www.national.com/wireless www.national.com/training PowerWise(R) Design University THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION ("NATIONAL") PRODUCTS. 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