Product Folder Order Now Support & Community Tools & Software Technical Documents LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 LMZ31707 7-A Power Module With 2.95-V to 17-V Input and Current Sharing in QFN Package 1 Features 3 Description * The LMZ31707 SIMPLE SWITCHER(R) power module is an easy-to-use integrated power solution that combines a 7-A DC-DC converter with power MOSFETs, a shielded inductor, and passives into a low profile, QFN package. This total power solution allows as few as three external components and eliminates the loop compensation and magnetics part selection process. 1 * * * * * * * * * * * * * * * * * * * Complete Integrated Power Solution Allows Small Footprint, Low-Profile Design 10 mm x 10 mm x 4.3 mm Package - Pin Compatible with LMZ31710 and LMZ31704 Efficiencies Up To 95% Eco-modeTM / Light Load Efficiency (LLE) Wide-Output Voltage Adjust 0.6 V to 5.5 V, with 1% Reference Accuracy Supports Parallel Operation for Higher Current Optional Split Power Rail Allows Input Voltage Down to 2.95 V Adjustable Switching Frequency (200 kHz to 1.2 MHz) Synchronizes to an External Clock Provides 180 out-of-phase Clock Signal Adjustable Slow-Start Output Voltage Sequencing / Tracking Power Good Output Programmable Undervoltage Lockout (UVLO) Over-Current & Over-Temperature Protection Pre-Bias Output Start-Up Operating Temperature Range: -40C to +85C Enhanced Thermal Performance: 13.3C/W Meets EN55022 Class B Emissions - Integrated Shielded Inductor Create a Custom Design Using the LMZ31707 With the WEBENCH(R) Power Designer 2 Applications * * * * Broadband and Communications Infrastructure Automated Test and Medical Equipment Compact PCI / PCI Express / PXI Express DSP and FPGA Point-of-Load Applications The 10x10x4.3 mm QFN package is easy to solder onto a printed circuit board and allows a compact point-of-load design. Achieves greater than 95% efficiency and excellent power dissipation capability with a thermal impedance of 13.3C/W. The LMZ31707 offers the flexibility and the feature-set of a discrete point-of-load design and is ideal for powering a wide range of ICs and systems. Advanced packaging technology affords a robust and reliable power solution compatible with standard QFN mounting and testing techniques. Simplified Application VIN CIN PVIN VIN ISHARE VOUT VOUT SENSE+ COUT LMZ31707 SYNC_OUT PWRGD INH/UVLO VADJ SS/TR RT/CLK STSEL AGND PGND RSET RRT 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 4 Specifications 4.1 Absolute Maximum Ratings (1) over operating temperature range (unless otherwise noted) Input Voltage Output Voltage MIN MAX UNIT VIN, PVIN -0.3 20 V INH/UVLO, PWRGD, RT/CLK, SENSE+ -0.3 6 V ILIM, VADJ, SS/TR, STSEL, SYNC_OUT, ISHARE, OCP_SEL -0.3 3 V PH -1.0 20 V -3 20 V -0.3 6 V PH 10ns Transient VOUT RT/CLK, INH/UVLO Source Current Sink Current 100 A PH current limit A PH current limit A PVIN current limit A -0.1 2 mA Operating Junction Temperature PWRGD -40 125 (2) C Storage Temperature -65 150 C Peak Reflow Case Temperature (3) 245 Maximum Number of Reflows Allowed (3) C 3 (4) Mechanical Shock Mil-STD-883D, Method 2002.3, 1 msec, 1/2 sine, mounted Mechanical Vibration Mil-STD-883D, Method 2007.2, 20-2000Hz (1) (4) 1500 G 20 Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. See the temperature derating curves in the Typical Characteristics section for thermal information. For soldering specifications, refer to the Soldering Requirements for BQFN Packages application note. Devices with a date code prior to week 14 2018 (1814) have a peak reflow case temperature of 240C with a maximum of one reflow. (2) (3) (4) 4.2 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN NOM MAX PVIN Input Switching Voltage VIN Input Bias Voltage VOUT Output Voltage 0.6 5.5 fSW Switching Frequency 200 1200 UNIT 2.95 17 V 4.5 17 V V kHz 4.3 Package Specifications LMZ31707 UNIT Weight Flammability MTBF Calculated reliability 2 1.45 grams Meets UL 94 V-O Per Bellcore TR-332, 50% stress, TA = 40C, ground benign Submit Documentation Feedback 37.4 MHrs Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 4.4 Thermal Information LMZ31707 THERMAL METRIC (1) RVQ42 UNIT 42 PINS Junction-to-ambient thermal resistance (2) JA JT Junction-to-top characterization parameter JB Junction-to-board characterization parameter (4) (1) (2) (3) (4) 13.3 C/W 1.6 C/W 5.3 C/W (3) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. The junction-to-ambient thermal resistance, JA, applies to devices soldered directly to a 100 mm x 100 mm double-sided PCB with 2 oz. copper and natural convection cooling. Additional airflow reduces JA. The junction-to-top characterization parameter, JT, estimates the junction temperature, TJ, of a device in a real system, using a procedure described in JESD51-2A (sections 6 and 7). TJ = JT * Pdis + TT; where Pdis is the power dissipated in the device and TT is the temperature of the top of the device. The junction-to-board characterization parameter, JB, estimates the junction temperature, TJ, of a device in a real system, using a procedure described in JESD51-2A (sections 6 and 7). TJ = JB * Pdis + TB; where Pdis is the power dissipated in the device and TB is the temperature of the board 1mm from the device. 4.5 Electrical Characteristics Over -40C to 85C free-air temperature, PVIN = VIN = 12 V, VOUT = 1.8 V, IOUT = 7 A, CIN = 0.1 F + 2 x 22 F ceramic + 100 F bulk, COUT = 4 x 47 F ceramic (unless otherwise noted) PARAMETER TEST CONDITIONS IOUT Output current TA = 85C, natural convection VIN Input bias voltage range PVIN Input switching voltage range UVLO VIN Undervoltage lockout VOUT(adj) VOUT A 4.5 17 V Over output current range 2.95 (2) 17 (3) V VIN Increasing Output voltage adjust range Over output current range 0.6 Set-point voltage tolerance TA = 25C, IOUT = 0 A Temperature variation -40C TA +85C, IOUT = 0 A 0.2% Line regulation Over input voltage range 0.1% Load regulation Over output current range 0.2% Total output voltage variation Includes set-point, line, load, and temperature variation Efficiency Transient response (1) (2) (3) (4) 4.0 3.5 Current limit threshold UNIT Over output current range VIN Decreasing Output voltage ripple MAX 7 PVIN = VIN = 5 V IO = 4 A ILIM TYP 0 PVIN = VIN = 12 V IO = 4 A MIN (1) 4.5 3.85 5.5 V V 1% (4) 1.5% (4) VOUT = 5.0 V, fSW = 1 MHz 94 % VOUT = 3.3 V, fSW = 750 kHz 92 % VOUT = 2.5 V, fSW = 750 kHz 90 % VOUT = 1.8 V, fSW = 500 kHz 89 % VOUT = 1.2 V, fSW = 300 kHz 87 % VOUT = 0.9 V, fSW = 250 kHz 85 % VOUT = 0.6 V, fSW = 200 kHz 82 % VOUT = 3.3 V, fSW = 750 kHz 95 % VOUT = 2.5 V, fSW = 750 kHz 93 % VOUT = 1.8 V, fSW = 500 kHz 92 % VOUT = 1.2 V, fSW = 300 kHz 90 % VOUT = 0.9 V, fSW = 250 kHz 87 % VOUT = 0.6 V, fSW = 200 kHz 84 % 20 MHz bandwith 14 mVP-P ILIM pin open 12 A ILIM pin to AGND 1.0 A/s load step from 25 to 75% IOUT(max) 9 A Recovery time tbd s VOUT over/undershoot tbd mV See the Light Load Efficiency (LLE) section for more information for output voltages < 1.5 V. The minimum PVIN is 2.95 V or (VOUT + 0.7 V), whichever is greater. See Table 7 for more details. The maximum PVIN voltage is 17 V or (22 x VOUT), whichever is less. See Table 7 for more details. The stated limit of the set-point voltage tolerance includes the tolerance of both the internal voltage reference and the internal adjustment resistor. The overall output voltage tolerance will be affected by the tolerance of the external RSET resistor. Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 3 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com Electrical Characteristics (continued) Over -40C to 85C free-air temperature, PVIN = VIN = 12 V, VOUT = 1.8 V, IOUT = 7 A, CIN = 0.1 F + 2 x 22 F ceramic + 100 F bulk, COUT = 4 x 47 F ceramic (unless otherwise noted) (1) PARAMETER VINH Inhibit threshold voltage IINH II(stby) TEST CONDITIONS Inhibit Low Voltage -0.3 1.1 INH Input current VINH < 1.1 V -1.15 INH Hysteresis current VINH > 1.3 V -3.3 Input standby current INH pin to AGND PWRGD Thresholds VOUT falling PWRGD Low Voltage I(PWRGD) = 0.5 mA Switching frequency RRT = 169 k fCLK Synchronization frequency VCLK-H CLK High-Level VCLK-L CLK Low-Level DCLK CLK Duty Cycle Thermal Shutdown 2 Good 95% Fault 108% Fault 91% Good 104% CLK Control Equivalent series resistance (ESR) (5) (6) (7) (8) 4 A 200 1200 kHz 2.0 5.5 500 50 V 80 % 175 C 10 C F 100 (6) 47 (7) V 0.5 44 (6) Non-ceramic Non-ceramic A 10 V Thermal shutdown hysteresis External output capacitance A kHz Thermal shutdown Ceramic V 0.3 20 Ceramic UNIT 600 400 External input capacitance COUT MAX open (5) fSW CIN TYP 1.3 VOUT rising Power Good MIN Inhibit High Voltage 200 1500 220 (7) 5000 (8) 35 F m This pin has an internal pull-up. If it is left open, the device operates when input power is applied. A small, low-leakage MOSFET is recommended for control. When the device is operating and no UVLO resistor divider is present on this pin, the open voltage is typically 2.9 V. A minimum of 44 F of external ceramic capacitance is required across the input (VIN and PVIN connected) for proper operation. An additional 100 F of bulk capacitance is recommended. It is also recommended to place a 0.1 F ceramic capacitor directly across the PVIN and PGND pins of the device. Locate the input capacitance close to the device. When operating with split VIN and PVIN rails, place 4.7F of ceramic capacitance directly at the VIN pin. See Table 4 for more details. The amount of required output capacitance varies depending on the output voltage (see Table 3 ). The amount of required capacitance must include at least 1x 47F ceramic capacitor. Locate the capacitance close to the device. Adding additional capacitance close to the load improves the response of the regulator to load transients. See Table 3 and Table 4 more details. When using both ceramic and non-ceramic output capacitors, the combined maximum must not exceed 5000 F. It may be necessary to increase the slow start time when turning on into the maximum capacitance. See theSlow Start (SS/TR) section for information on adjusting the slow start time. Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 5 Device Information Functional Block Diagram OCP_SEL ILIM OCP INH/UVLO Shutdown Logic PWRGD VIN Thermal Shutdown SENSE+ VIN UVLO PWRGD Logic PVIN + + PH VADJ SS/TR VREF Comp STSEL Current Share ISHARE SYNC_OUT RT/CLK Power Stage and Control Logic VOUT Oscillator with PLL PGND AGND LMZ31707 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 5 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com Pin Functions TERMINAL NAME DESCRIPTION NO. 2 AGND 23 Zero volt reference for the analog control circuit. These pins are not connected together internal to the device and must be connected to one another using an AGND plane of the PCB. These pins are associated with the internal analog ground (AGND) of the device. Keep AGND seperate from PGND, as a single connection is made internal to the device. See Layout Recommendations. 20 21 PGND 31 32 This is the return current path for the power stage of the device. Connect these pins to the load and to the bypass capacitors associated with PVIN and VOUT. Keep PGND seperate from AGND, as a single connection is made internal to the device. 33 VIN 3 Input bias voltage pin. Supplies the control circuitry of the power converter. Connect this pin to the input bias supply. Connect bypass capacitors between this pin and PGND. 1 11 PVIN 12 Input switching voltage. Supplies voltage to the power switches of the converter. Connect these pins to the input supply. Connect bypass capacitors between these pins and PGND. 39 40 34 35 36 VOUT 37 Output voltage. These pins are connected to the internal output inductor. Connect these pins to the output load and connect external bypass capacitors between these pins and PGND. 38 41 10 13 14 15 PH 16 17 Phase switch node. These pins must be connected to one another using a small copper island under the device for thermal relief. Do not place any external component on these pins or tie them to a pin of another function. 18 19 42 5 DNC 9 Do Not Connect. Do not connect these pins to AGND, to another DNC pin, or to any other voltage. These pins are connected to internal circuitry. Each pin must be soldered to an isolated pad. 24 ISHARE 25 Current share pin. Connect this pin to other LMZ31707 device's ISHARE pin when paralleling multple LMZ31707 devices. When unused, treat this pin as a Do Not Connect (DNC) and leave it isolated from all other signals or ground. OCP_SEL 4 Over current protection select pin. Leave this pin open for hiccup mode operation. Connect this pin to AGND for cycle-by-cycle operation. See Overcurrent Protection for more details. ILIM 6 Current limit pin. Leave this pin open for full current limit threshold. Connect this pin to AGND to reduce the current limit threshold by appoximately 3 A. SYNC_OUT 7 Synchronization output pin. Provides a 180 out-of-phase clock signal. PWRGD 8 Power Good flag pin. This open drain output asserts low if the output voltage is more than approximately 6% out of regulation. A pull-up resistor is required. RT/CLK 22 This pin is connected to an internal frequency setting resistor which sets the default switching frequency. An external resistor can be connected from this pin to AGND to increase the frequency. This pin can also be used to synchronize to an external clock. VADJ 26 Connecting a resistor between this pin and AGND sets the output voltage. SENSE+ 27 Remote sense connection. This pin must be connected to VOUT at the load or at the device pins. Connect this pin to VOUT at the load for improved regulation. 6 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 Pin Functions (continued) TERMINAL DESCRIPTION NAME NO. SS/TR 28 Slow-start and tracking pin. Connecting an external capacitor to this pin adjusts the output voltage rise time. A voltage applied to this pin allows for tracking and sequencing control. STSEL 29 Slow-start or track feature select. Connect this pin to AGND to enable the internal SS capacitor. Leave this pin open to enable the TR feature. INH/UVLO 30 Inhibit and UVLO adjust pin. Use an open drain or open collector logic device to ground this pin to control the INH function. A resistor divider between this pin, AGND, and PVIN/VIN sets the UVLO voltage. PVIN 1 AGND 2 VIN 40 39 PGND PGND VOUT VOUT VOUT VOUT VOUT PVIN PVIN RVQ PACKAGE (TOP VIEW) 38 37 36 35 34 33 32 31 PGND 30 INH/UVLO 3 29 STSEL OCP_SEL 4 28 SS/TR DNC 5 27 SENSE+ ILIM 6 26 VADJ SYNC_OUT 7 25 ISHARE PWRGD 8 24 DNC DNC 9 23 AGND 22 RT/CLK 21 PGND PGND PH PH PH 14 15 16 17 18 19 20 PH 12 13 PH 11 PH PH PVIN 42 PH 10 PVIN PH 41 VOUT Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 7 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 6 Typical Characteristics (PVIN = VIN = 12 V) The electrical characteristic data has been developed from actual products tested at 25C. This data is considered typical for the converter. Applies to Figure 1, Figure 2, and Figure 3. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to devices soldered directly to a 100 mm x 100 mm, 4-layer PCB with 2 oz. copper. Applies to Figure 4. 30 100 Output Ripple Voltage (mV) 90 70 Vo = 5.0V, fsw = 1MHz Vo = 3.3V, fsw = 750kHz Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz 60 50 40 0 1 2 3 4 5 6 Output Current (A) 25 20 15 10 5 0 7 2.5 1.5 1.0 50 20 4 5 6 Output Current (A) 7 Airflow = 0 LFM 40 0.0 3 All Output Voltages 0 Gain (dB) 1 2 3 4 5 Output Current (A) C004 Figure 3. Power Dissipation vs. Output Current 6 7 C001 Figure 4. Safe Operating Area 40 120 30 90 20 60 10 30 0 0 -30 10 -60 20 30 7 C004 60 30 2 6 70 0.5 1 5 80 2.0 0 4 Figure 2. Voltage Ripple vs. Output Current Ambient Temperature (C) Power Dissipation (W) 3.0 3 90 Vo = 5.0V, fsw = 1MHz Vo = 3.3V, fsw = 750kHz Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz 3.5 2 Output Current (A) Figure 1. Efficiency vs. Output Current 4.0 1 C001 Phase () Efficiency (%) 80 Vo = 5.0V, fsw = 1MHz Vo = 3.3V, fsw = 750kHz Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz Gain -90 Phase 40 1000 -120 10k 100k Frequency (kHz) C001 Figure 5. VOUT= 1.8 V, IOUT= 7 A, COUT= 200 F ceramic, fSW= 500 kHz 8 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 7 Typical Characteristics (PVIN = VIN = 5 V) The electrical characteristic data has been developed from actual products tested at 25C. This data is considered typical for the converter. Applies to Figure 6, Figure 7, and Figure 8. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to devices soldered directly to a 100 mm x 100 mm, 4-layer PCB with 2 oz. copper. Applies to Figure 9. 100 30 Output Voltage Ripple (mV) 80 70 Vo = 3.3V, fsw = 750kHz Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz Vo = 0.6V, fsw = 200kHz 60 50 40 0 1 2 3 4 5 6 Output Current (A) 25 20 15 10 5 7 0 4 5 6 7 C004 Figure 7. Voltage Ripple vs. Output Current 80 Ambient Temperature (C) Power Dissipation (W) 2.0 3 90 Vo = 3.3V, fsw = 750kHz Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz Vo = 0.6V, fsw = 200kHz 2.5 2 Output Current (A) Figure 6. Efficiency vs. Output Current 3.0 1 C001 1.5 1.0 0.5 70 60 50 Airflow = 0 LFM 40 30 0.0 All Output Voltages 20 0 1 2 3 4 5 6 Output Current (A) 7 0 2 4 5 6 7 C001 Figure 9. Safe Operating Area 40 120 30 90 20 60 10 30 0 0 -30 10 -60 20 30 3 Output Current (A) Figure 8. Power Dissipation vs. Output Current Gain (dB) 1 C004 Phase () Efficiency (%) 90 Vo = 3.3V, fsw = 750kHz Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz Vo = 0.6V, fsw = 200kHz Gain -90 Phase 40 1000 -120 10k 100k Frequency (kHz) C001 Figure 10. VOUT= 1.8 V, IOUT= 7 A, COUT= 200 F ceramic, fSW= 500 kHz Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 9 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 8 Typical Characteristics (PVIN = 3.3 V, VIN = 5 V) The electrical characteristic data has been developed from actual products tested at 25C. This data is considered typical for the converter. Applies to Figure 11, Figure 12, and Figure 13. The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum operating temperatures. Derating limits apply to devices soldered directly to a 100 mm x 100 mm, 4-layer PCB with 2 oz. copper. Applies to Figure 14. 100 30 Output Ripple Voltage (mV) 90 70 Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz 60 Vo = 1.2V, fsw = 300kHz 50 Vo = 0.9V, fsw = 250kHz Vo = 0.6V, fsw = 200kHz 40 0 1 2 3 4 5 6 25 20 15 10 5 7 Output Current (A) 0 4 5 6 7 C004 Figure 12. Voltage Ripple vs. Output Current 80 Ambient Temperature (C) Power Dissipation (W) 2.0 3 90 Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz Vo = 0.6V, fsw = 200kHz 2.5 2 Output Current (A) Figure 11. Efficiency vs. Output Current 3.0 1 C001 1.5 1.0 0.5 70 60 50 Airflow = 0 LFM 40 30 0.0 All Output Voltages 20 0 1 2 3 4 5 6 7 Output Current (A) 0 2 4 5 6 7 C001 Figure 14. Safe Operating Area 40 120 30 90 20 60 10 30 0 0 -30 10 -60 20 30 3 Output Current (A) Figure 13. Power Dissipation vs. Output Current Gain (dB) 1 C004 Phase () Efficiency (%) 80 Vo = 2.5V, fsw = 750kHz Vo = 1.8V, fsw = 500kHz Vo = 1.2V, fsw = 300kHz Vo = 0.9V, fsw = 250kHz Vo = 0.6V, fsw = 200kHz Gain -90 Phase 40 1000 -120 10k 100k Frequency (kHz) C001 Figure 15. VOUT= 1.8 V, IOUT= 7 A, COUT= 200 F ceramic, fSW= 500 kHz 10 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9 Application Information 9.1 Adjusting the Output Voltage The VADJ control sets the output voltage of the LMZ31707. The output voltage adjustment range is from 0.6V to 5.5V. The adjustment method requires the addition of RSET, which sets the output voltage, the connection of SENSE+ to VOUT, and in some cases RRT which sets the switching frequency. The RSET resistor must be connected directly between the VADJ (pin 26) and AGND (pin 23). The SENSE+ pin (pin 27) must be connected to VOUT either at the load for improved regulation or at VOUT of the device. The RRT resistor must be connected directly between the RT/CLK (pin 22) and AGND (pin 23). Table 1 gives the standard external RSET resistor for a number of common bus voltages, along with the recommended RRT resistor for that output voltage. Table 1. Standard RSET Resistor Values for Common Output Voltages RESISTORS OUTPUT VOLTAGE VOUT (V) 0.9 1.0 1.2 1.8 2.5 3.3 5.0 RSET (k) 2.87 2.15 1.43 0.715 0.453 0.316 0.196 RRT (k) 1000 1000 487 169 90.9 90.9 63.4 For other output voltages, the value of the required resistor can either be calculated using the following formula, or simply selected from the range of values given in Table 2. 1.43 RSET = (kW ) ae ae VOUT o o cc / - 1/ e e 0.6 o o (1) Table 2. Standard RSET Resistor Values VOUT (V) RSET (k) RRT(k) fSW(kHz) VOUT (V) RSET (k) RRT(k) fSW(kHz) 0.6 open OPEN 200 3.1 0.348 90.9 750 0.7 8.66 OPEN 200 3.2 0.332 90.9 750 0.8 4.32 OPEN 200 3.3 0.316 90.9 750 0.9 2.87 1000 250 3.4 0.309 90.9 750 1.0 2.15 1000 250 3.5 0.294 90.9 750 1.1 1.74 1000 250 3.6 0.287 90.9 750 1.2 1.43 487 300 3.7 0.280 90.9 750 1.3 1.24 487 300 3.8 0.267 90.9 750 1.4 1.07 487 300 3.9 0.261 90.9 750 1.5 0.953 487 300 4.0 0.255 90.9 750 1.6 0.866 487 300 4.1 0.243 63.4 1000 1.7 0.787 487 300 4.2 0.237 63.4 1000 1.8 0.715 169 500 4.3 0.232 63.4 1000 1.9 0.665 169 500 4.4 0.226 63.4 1000 2.0 0.619 169 500 4.5 0.221 63.4 1000 2.1 0.576 169 500 4.6 0.215 63.4 1000 2.2 0.536 169 500 4.7 0.210 63.4 1000 2.3 0.511 169 500 4.8 0.205 63.4 1000 2.4 0.475 169 500 4.9 0.200 63.4 1000 2.5 0.453 90.9 750 5.0 0.196 63.4 1000 2.6 0.432 90.9 750 5.1 0.191 63.4 1000 2.7 0.412 90.9 750 5.2 0.187 63.4 1000 2.8 0.392 90.9 750 5.3 0.182 63.4 1000 2.9 0.374 90.9 750 5.4 0.178 63.4 1000 3.0 0.357 90.9 750 5.5 0.174 63.4 1000 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 11 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 9.2 Capacitor Recommendations for the LMZ31707 Power Supply 9.2.1 Capacitor Technologies 9.2.1.1 Electrolytic, Polymer-Electrolytic Capacitors When using electrolytic capacitors, high-quality, computer-grade electrolytic capacitors are recommended. Polymer-electrolytic type capacitors are recommended for applications where the ambient operating temperature is less than 0C. The Sanyo OS-CON capacitor series is suggested due to the lower ESR, higher rated surge, power dissipation, ripple current capability, and small package size. Aluminum electrolytic capacitors provide adequate decoupling over the frequency range of 2 kHz to 150 kHz, and are suitable when ambient temperatures are above 0C. 9.2.1.2 Ceramic Capacitors The performance of aluminum electrolytic capacitors is less effective than ceramic capacitors above 150 kHz. Multilayer ceramic capacitors have a low ESR and a resonant frequency higher than the bandwidth of the regulator. They can be used to reduce the reflected ripple current at the input as well as improve the transient response of the output. 9.2.1.3 Tantalum, Polymer-Tantalum Capacitors Polymer-tantalum type capacitors are recommended for applications where the ambient operating temperature is less than 0C. The Sanyo POSCAP series and Kemet T530 capacitor series are recommended rather than many other tantalum types due to their lower ESR, higher rated surge, power dissipation, ripple current capability, and small package size. Tantalum capacitors that have no stated ESR or surge current rating are not recommended for power applications. 9.2.2 Input Capacitor The LMZ31707 requires a minimum input capacitance of 44 F of ceramic type. An additional 100 F of nonceramic capacitance is recommended for applications with transient load requirements. The voltage rating of input capacitors must be greater than the maximum input voltage. At worst case, when operating at 50% duty cycle and maximum load, the combined ripple current rating of the input capacitors must be at least 3.5 Arms. Table 4 includes a preferred list of capacitors by vendor. It is also recommended to place a 0.1 F ceramic capacitor directly across the PVIN and PGND pins of the device. When operating with split VIN and PVIN rails, place 4.7F of ceramic capacitance directly at the VIN pin. 9.2.3 Output Capacitor The required output capacitance is determined by the output voltage of the LMZ31707. See Table 3 for the amount of required capacitance. The effects of temperature and capacitor voltage rating must be considered when selecting capacitors to meet the minimum required capacitance. The required output capacitance can be comprised of all ceramic capacitors, or a combination of ceramic and bulk capacitors. The required capacitance must include at least one 47 F ceramic. When adding additional non-ceramic bulk capacitors, low-ESR devices like the ones recommended in Table 4 are required. The required capacitance above the minimum is determined by actual transient deviation requirements. Table 4 includes a preferred list of capacitors by vendor. Table 3. Required Output Capacitance VOUT RANGE (V) (1) 12 MINIMUM REQUIRED COUT (F) MIN MAX 0.6 < 0.8 500 F (1) 0.8 < 1.2 300 F (1) 1.2 < 3.0 200 F (1) 3.0 < 4.0 100 F (1) 4.0 5.5 47 F ceramic Minimum required must include at least one 47 F ceramic capacitor. Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 Table 4. Recommended Input/Output Capacitors (1) CAPACITOR CHARACTERISTICS VENDOR SERIES PART NUMBER WORKING VOLTAGE (V) CAPACITANCE (F) ESR (2) (m) Murata X5R GRM32ER61E226K 25 22 2 TDK X5R C3225X5R0J107M 6.3 100 2 TDK X5R C3225X5R0J476K 6.3 47 2 Murata X5R GRM32ER60J107M 6.3 100 2 Murata X5R GRM32ER60J476M 6.3 47 2 100 30 Panasonic EEH-ZA EEH-ZA1E101XP 25 Sanyo POSCAP 16TQC68M 16 68 50 Kemet T520 T520V107M010ASE025 10 100 25 Sanyo POSCAP 10TPE220ML 10 220 25 Sanyo POSCAP 6TPE100MI 6.3 100 25 Sanyo POSCAP 2R5TPE220M7 2.5 220 7 Kemet T530 T530D227M006ATE006 6.3 220 6 Kemet T530 T530D337M006ATE010 6.3 330 10 Sanyo POSCAP 2TPF330M6 2.0 330 6 Sanyo POSCAP 6TPE330MFL 6.3 330 15 (1) (2) Capacitor Supplier Verification, RoHS, Lead-free and Material Details Consult capacitor suppliers regarding availability, material composition, RoHS and lead-free status, and manufacturing process requirements for any capacitors identified in this table. Maximum ESR @ 100kHz, 25C. 9.3 Transient Response Table 5. Output Voltage Transient Response CIN1 = 3x 22 F CERAMIC, CIN2 = 100 F POLYMER-TANTALUM VOLTAGE DEVIATION (mV) VOUT (V) 0.6 COUT1 Ceramic COUT2 BULK 2 A LOAD STEP, (1 A/s) 3.5 A LOAD STEP, (1 A/s) 5 500 F 220 F 30 45 90 12 500 F 220 F 30 45 90 300 F 220 F 40 65 95 300 F 470 F 35 60 95 300 F 220 F 35 60 95 300 F 470 F 30 55 95 200 F 220 F 50 85 100 200 F 470 F 45 75 100 200 F 220 F 45 80 100 200 F 470 F 40 70 100 200 F 220 F 70 105 110 200 F 470 F 65 90 110 200 F 220 F 65 100 120 200 F 470 F 60 90 120 5 100 F 220 F 105 177 130 12 100 F 220 F 115 190 150 5 0.9 12 5 1.2 12 5 1.8 12 3.3 RECOVERY TIME (s) VIN (V) Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 13 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 9.4 Transient Waveforms 14 Figure 16. PVIN = 12V, VOUT = 1.2V, 3.5A Load Step Figure 17. PVIN = 12V, VOUT = 1.8V, 3.5A Load Step Figure 18. PVIN = 5V, VOUT = 0.9V, 2.5A Load Step Figure 19. PVIN = 5V, VOUT = 1.8V, 3.5A Load Step Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.5 Application Schematics LMZ31707 VIN VIN / PVIN 4.5 V to 17 V VOUT 1.2 V SENSE+ PVIN VOUT + + CIN1 CIN2 100 F 47 F CIN3 0.1 F ISHARE SYNC_OUT COUT1 2x 100 F COUT2 220 F PWRGD INH/UVLO RT/CLK SS/TR RRT 487 k VADJ STSEL AGND PGND RSET 1.43 k Figure 20. Typical Schematic PVIN = VIN = 4.5 V to 17 V, VOUT = 1.2 V LMZ31707 VIN VIN / PVIN 4.5 V to 17 V PVIN VOUT 3.3 V SENSE+ VOUT + + CIN1 CIN2 100 F 47 F CIN3 0.1 F COUT1 100 F ISHARE SYNC_OUT COUT2 220 F PWRGD INH/UVLO RT/CLK SS/TR VADJ STSEL AGND PGND RSET 316 RRT 90.9 k Figure 21. Typical Schematic PVIN = VIN = 4.5 V to 17 V, VOUT = 3.3 V Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 15 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com Application Schematics (continued) VIN 4.5 V to 17 V CIN3 4.7 F VIN LMZ31707 VOUT 1.0 V SENSE+ PVIN 3.3 V PVIN VOUT + + CIN1 CIN2 100 F 47 F CIN3 0.1 F COUT1 3x 100 F ISHARE SYNC_OUT COUT2 220 F PWRGD INH/UVLO RT/CLK SS/TR VADJ STSEL AGND PGND RSET 2.15 k RRT 1M Figure 22. Typical Schematic PVIN = 3.3 V, VIN = 4.5 V to 17 V, VOUT = 1.0 V 9.6 Custom Design With WEBENCH(R) Tools Click here to create a custom design using the LMZ31707 device with the WEBENCH(R) Power Designer. 1. Start by entering the input voltage (VIN), output voltage (VOUT), and output current (IOUT) requirements. 2. Optimize the design for key parameters such as efficiency, footprint, and cost using the optimizer dial. 3. Compare the generated design with other possible solutions from Texas Instruments. The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time pricing and component availability. In most cases, these actions are available: * Run electrical simulations to see important waveforms and circuit performance * Run thermal simulations to understand board thermal performance * Export customized schematic and layout into popular CAD formats * Print PDF reports for the design, and share the design with colleagues Get more information about WEBENCH tools at www.ti.com/WEBENCH. 9.7 VIN and PVIN Input Voltage The LMZ31707 allows for a variety of applications by using the VIN and PVIN pins together or separately. The VIN voltage supplies the internal control circuits of the device. The PVIN voltage provides the input voltage to the power converter system. If tied together, the input voltage for the VIN pin and the PVIN pin can range from 4.5 V to 17 V. If using the VIN pin separately from the PVIN pin, the VIN pin must be greater than 4.5 V, and the PVIN pin can range from as low as 2.95 V to 17 V. When operating from a split rail, it is recommended to supply VIN from 5 V to 12 V, for best performance. A voltage divider connected to the INH/UVLO pin can adjust either input voltage UVLO appropriately. See the Programmable Undervoltage Lockout (UVLO) section of this datasheet for more information. 16 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.8 3.3 V PVIN Operation Applications operating from a PVIN of 3.3 V must provide at least 4.5 V for VIN. It is recommended to supply VIN from 5 V to 12 V, for best performance. See listeraure number SNVA692 for help creating 5 V from 3.3 V using a small, simple charge pump device. 9.9 Power Good (PWRGD) The PWRGD pin is an open drain output. Once the voltage on the SENSE+ pin is between 95% and 104% of the set voltage, the PWRGD pin pull-down is released and the pin floats. The recommended pull-up resistor value is between 10 k and 100 k to a voltage source that is 5.5 V or less. The PWRGD pin is in a defined state once VIN is greater than 1.0 V, but with reduced current sinking capability. The PWRGD pin achieves full current sinking capability once the VIN pin is above 4.5V. The PWRGD pin is pulled low when the voltage on SENSE+ is lower than 91% or greater than 108% of the nominal set voltage. Also, the PWRGD pin is pulled low if the input UVLO or thermal shutdown is asserted, the INH pin is pulled low, or the SS/TR pin is below 1.4 V. 9.10 SYNC_OUT The LMZ31707 provides a 180 out-of-phase clock signal for applications requiring synchronization. The SYNC_OUT pin produces a 50% duty cycle clock signal that is the same frequency as the device's switching frequency, but is 180 out of phase. Operating two devices 180 out of phase reduces input and output voltage ripple. The SYNC_OUT clock signal is compatible with other LMZ3 devices that have a CLK input. 9.11 Parallel Operation Up to six LMZ31707 devices can be paralleled for increased output current. Multiple connections must be made between the paralleled devices and the component selection is slightly different than for a stand-alone LMZ31707 device. A typical LMZ31707 parallel schematic is shown in Figure 23. Refer to application note, SNVA695 for information and design help when paralleling multiple LMZ31707 devices. VIN = 12V PWRGD VIN PVIN SENSE+ 220F 22F 0.1F VOUT LMZ31707 22F 100F 100F VADJ SS/TR PGND RSET 715 0.1F LMZ31707 PWRGD SENSE+ VOUT SYNC_OUT RT/CLK 330F VADJ VIN PVIN 100F AGND CSS SS/TR Voltage Supervisor CSH INH Control ISHARE 5V 100F STSEL ISHARE RRT 169k INH/UVLO Sync Freq 500KHz INH/UVLO SYNC_OUT RT/CLK VO = 1.8V STSEL AGND RRT 169k PGND Figure 23. Typical LMZ31707 Parallel Schematic Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 17 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 9.12 Light Load Efficiency (LLE) The LMZ31707 operates in pulse skip mode at light load currents to improve efficiency and decrease power dissipation by reducing switching and gate drive losses. These pulses may cause the output voltage to rise when there is no load to discharge the energy. For output voltages < 1.5 V, a minimum load is required. The amount of required load can be determined by Equation 2. In most cases the minimum current drawn by the load circuit will be enough to satisfy this load. Applications requiring a load resistor to meet the minimum load, the added power dissipation will be 3.6 mW. A single 0402 size resistor across VOUT and PGND can be used. (2) When VOUT = 0.6 V and RSET = OPEN, the minimum load current is 600 A. 9.13 Power-Up Characteristics When configured as shown in the front page schematic, the LMZ31707 produces a regulated output voltage following the application of a valid input voltage. During the power-up, internal soft-start circuitry slows the rate that the output voltage rises, thereby limiting the amount of in-rush current that can be drawn from the input source. Figure 24 shows the start-up waveforms for a LMZ31707, operating from a 5-V input (PVIN=VIN) and with the output voltage adjusted to 1.8 V. Figure 25 shows the start-up waveforms for a LMZ31707 starting up into a pre-biased output voltage. The waveforms were measured with a 5-A constant current load. Figure 24. Start-Up Waveforms 18 Submit Documentation Feedback Figure 25. Start-up into Pre-bias Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.14 Pre-Biased Start-Up The LMZ31707 has been designed to prevent the low-side MOSFET from discharging a pre-biased output. During pre-biased startup, the low-side MOSFET does not turn on until the high-side MOSFET has started switching. The high-side MOSFET does not start switching until the slow start voltage exceeds the voltage on the VADJ pin. Refer to Figure 25. 9.15 Remote Sense The SENSE+ pin must be connected to VOUT at the load, or at the device pins. Connecting the SENSE+ pin to VOUT at the load improves the load regulation performance of the device by allowing it to compensate for any I-R voltage drop between its output pins and the load. An I-R drop is caused by the high output current flowing through the small amount of pin and trace resistance. This should be limited to a maximum of 300 mV. NOTE The remote sense feature is not designed to compensate for the forward drop of nonlinear or frequency dependent components that may be placed in series with the converter output. Examples include OR-ing diodes, filter inductors, ferrite beads, and fuses. When these components are enclosed by the SENSE+ connection, they are effectively placed inside the regulation control loop, which can adversely affect the stability of the regulator. 9.16 Thermal Shutdown The internal thermal shutdown circuitry forces the device to stop switching if the junction temperature exceeds 175C typically. The device reinitiates the power up sequence when the junction temperature drops below 165C typically. Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 19 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 9.17 Output On/Off Inhibit (INH) The INH pin provides electrical on/off control of the device. Once the INH pin voltage exceeds the threshold voltage, the device starts operation. If the INH pin voltage is pulled below the threshold voltage, the regulator stops switching and enters low quiescent current state. The INH pin has an internal pull-up current source, allowing the user to float the INH pin for enabling the device. If an application requires controlling the INH pin, use an open drain/collector device, or a suitable logic gate to interface with the pin. Using a voltage superviser to control the INH pin allows control of the turn-on and turn-off of the device as opposed to relying on the ramp up or down if the input voltage source. Figure 26 shows the typical application of the inhibit function. Turning Q1 on applies a low voltage to the inhibit control (INH) pin and disables the output of the supply, shown in Figure 27. If Q1 is turned off, the supply executes a soft-start power-up sequence, as shown in Figure 28. A regulated output voltage is produced within 2 ms. The waveforms were measured with a 5-A constant current load. INH/UVLO Q1 INH Control AGND STSEL SS/TR Figure 26. Typical Inhibit Control Figure 27. Inhibit Turn-Off 20 Figure 28. Inhibit Turn-On Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.18 Slow Start (SS/TR) Connecting the STSEL pin to AGND and leaving SS/TR pin open enables the internal SS capacitor with a slow start interval of approximately 1.2 ms. Adding additional capacitance between the SS pin and AGND increases the slow start time. Increasing the slow start time will reduce inrush current seen by the input source and reduce the current seen by the device when charging the output capacitors. To avoid the activation of current limit and ensure proper start-up, the SS capacitor may need to be increased when operating near the maximum output capacitance limit. Figure 29 shows an additional SS capacitor connected to the SS/TR pin and the STSEL pin connected to AGND. See Table 6 below for SS capacitor values and timing interval. SS/TR CSS (Optional) AGND STSEL Figure 29. Slow-Start Capacitor (CSS) and STSEL Connection Table 6. Slow-Start Capacitor Values and Slow-Start Time CSS (nF) open 3.3 4.7 10 15 22 33 SS Time (msec) 1.2 2.1 2.5 3.8 5.1 7.0 9.8 9.19 Overcurrent Protection For protection against load faults, the LMZ31707 incorporates output overcurrent protection. The overcurrent protection mode can be selected using the OCP_SEL pin. Leaving the OCP_SEL pin open selects hiccup mode and connecting it to AGND selects cycle-by-cycle mode. In hiccup mode, applying a load that exceeds the regulator's overcurrent threshold causes the regulated output to shut down. Following shutdown, the module periodically attempts to recover by initiating a soft-start power-up as shown in Figure 30. This is described as a hiccup mode of operation, whereby the module continues in a cycle of successive shutdown and power up until the load fault is removed. During this period, the average current flowing into the fault is significantly reduced which reduces power dissipation. Once the fault is removed, the module automatically recovers and returns to normal operation as shown in Figure 31. In cycle-by-cycle mode, applying a load that exceeds the regulator's overcurrent threshold limits the output current and reduces the output voltage as shown in Figure 32. During this period, the current flowing into the fault remains high causing the power dissipation to stay high as well. Once the overcurrent condition is removed, the output voltage returns to the set-point voltage as shown in Figure 33. Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 21 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com Overcurrent Protection (continued) 22 Figure 30. Overcurrent Limiting (Hiccup) Figure 31. Removal of Overcurrent (Hiccup) Figure 32. Overcurrent Limiting (Cycle-by-Cycle) Figure 33. Removal of Overcurrent (Cycle-by-Cycle) Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.20 Synchronization (CLK) An internal phase locked loop (PLL) has been implemented to allow synchronization between 200 kHz and 1200 kHz, and to easily switch from RT mode to CLK mode. To implement the synchronization feature, connect a square wave clock signal to the RT/CLK pin with a duty cycle between 20% to 80%. The clock signal amplitude must transition lower than 0.5 V and higher than 2.0 V. The start of the switching cycle is synchronized to the falling edge of RT/CLK pin. In applications where both RT mode and CLK mode are needed, the device can be configured as shown in Figure 34. Before the external clock is present, the device works in RT mode and the switching frequency is set by RT resistor. When the external clock is present, the CLK mode overrides the RT mode. The first time the CLK pin is pulled above the RT/CLK high threshold (2.0 V), the device switches from RT mode to CLK mode and the RT/CLK pin becomes high impedance as the PLL starts to lock onto the frequency of the external clock. It is not recommended to switch from CLK mode back to RT mode because the internal switching frequency drops to 100 kHz first before returning to the switching frequency set by the RT resistor (RRT). External Clock 200 kHz to 1200 kHz RT/CLK RRT AGND Figure 34. RT/CLK Configuration The synchronization frequency must be selected based on the output voltages of the devices being synchronized. Table 7 shows the allowable frequencies for a given range of output voltages. For the most efficient solution, always synchronize to the lowest allowable frequency. For example, an application requires synchronizing three LMZ31707 devices with output voltages of 1.0 V, 1.2 V and 1.8 V, all powered from PVIN = 12 V. Table 7 shows that all three output voltages should be synchronized to 300 kHz. Table 7. Synchronization Frequency vs Output Voltage SYNCHRONIZATION FREQUENCY (kHz) PVIN = 12 V PVIN = 5 V VOUT RANGE (V) VOUT RANGE (V) MIN MAX MIN MAX 200 0.6 1.3 0.6 1.5 300 0.8 2.0 0.6 4.3 400 1.1 2.5 0.6 4.3 500 1.4 3.4 0.6 4.3 600 1.6 5.0 0.7 4.3 700 1.9 5.5 0.8 4.3 800 2.1 5.5 0.9 4.3 900 2.4 5.5 1.0 4.3 1000 2.7 5.5 1.1 4.3 1100 2.9 5.5 1.3 4.3 1200 3.2 5.5 1.4 4.3 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 23 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 9.21 Sequencing (SS/TR) Many of the common power supply sequencing methods can be implemented using the SS/TR, INH and PWRGD pins. The sequential method is illustrated in Figure 35 using two LMZ31707 devices. The PWRGD pin of the first device is coupled to the INH pin of the second device which enables the second power supply once the primary supply reaches regulation. Figure 36 shows sequential turn-on waveforms of two LMZ31707 devices. INH/UVLO VOUT1 VOUT STSEL PWRGD INH/UVLO VOUT2 VOUT STSEL PWRGD Figure 35. Sequencing Schematic Figure 36. Sequencing Waveforms Simultaneous power supply sequencing can be implemented by connecting the resistor network of R1 and R2 shown in Figure 37 to the output of the power supply that needs to be tracked or to another voltage reference source. The tracking voltage must exceed 750mV before VOUT2 reaches its set-point voltage. The PWRGD output of the VOUT2 device may remain low if the tracking voltage does not exceed 1.4V.Figure 38 shows simultaneous turn-on waveforms of two LMZ31707 devices. Use Equation 3 and Equation 4 to calculate the values of R1 and R2. R1 = (VOUT2 12.6 ) 0.6 R2 = (kW ) (3) 0.6 R1 (kW ) V ( OUT2 - 0.6 ) (4) VOUT1 VOUT INH/UVLO STSEL SS/TR VOUT2 VOUT INH/UVLO R1 STSEL SS/TR R2 Figure 37. Simultaneous Tracking Schematic 24 Figure 38. Simultaneous Tracking Waveforms Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.22 Programmable Undervoltage Lockout (UVLO) The LMZ31707 implements internal UVLO circuitry on the VIN pin. The device is disabled when the VIN pin voltage falls below the internal VIN UVLO threshold. The internal VIN UVLO rising threshold is 4.5 V(max) with a typical hysteresis of 150 mV. If an application requires either a higher UVLO threshold on the VIN pin or a higher UVLO threshold for a combined VIN and PVIN, then the UVLO pin can be configured as shown in Figure 39 or Figure 40. Table 8 lists standard values for RUVLO1 and RUVLO2 to adjust the VIN UVLO voltage up. PVIN PVIN VIN VIN RUVLO1 RUVLO1 INH/UVLO INH/UVLO RUVLO2 RUVLO2 Figure 39. Adjustable VIN UVLO Figure 40. Adjustable VIN and PVIN Undervoltage Lockout Table 8. Standard Resistor values for Adjusting VIN UVLO VIN UVLO (V) 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 RUVLO1 (k) 68.1 68.1 68.1 68.1 68.1 68.1 68.1 68.1 68.1 68.1 68.1 RUVLO2 (k) 21.5 18.7 16.9 15.4 14.0 13.0 12.1 11.3 10.5 9.76 9.31 Hysteresis (mV) 400 415 430 450 465 480 500 515 530 550 565 For a split rail application, if a secondary UVLO on PVIN is required, VIN must be 4.5V. Figure 41 shows the PVIN UVLO configuration. Use Table 9 to select RUVLO1 and RUVLO2 for PVIN. If PVIN UVLO is set for less than 3.5 V, a 5.1-V zener diode should be added to clamp the voltage on the UVLO pin below 6 V. > 4.5 V VIN PVIN RUVLO1 INH/UVLO RUVLO2 Figure 41. Adjustable PVIN Undervoltage Lockout, (VIN 4.5 V) Table 9. Standard Resistor Values for Adjusting PVIN UVLO, (VIN 4.5 V) PVIN UVLO (V) 2.9 3.0 3.5 4.0 4.5 RUVLO1 (k) 68.1 68.1 68.1 68.1 68.1 RUVLO2 (k) 47.5 44.2 34.8 28.7 24.3 Hysteresis (mV) 330 335 350 365 385 For higher PVIN UVLO voltages see Table 8 for resistor values Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 25 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 9.23 Layout Considerations To achieve optimal electrical and thermal performance, an optimized PCB layout is required. Figure 42 thru Figure 45, shows a typical PCB layout. Some considerations for an optimized layout are: * Use large copper areas for power planes (PVIN, VOUT, and PGND) to minimize conduction loss and thermal stress. * Place ceramic input and output capacitors close to the device pins to minimize high frequency noise. * Locate additional output capacitors between the ceramic capacitor and the load. * Keep AGND and PGND separate from one another. * Place RSET, RRT, and CSS as close as possible to their respective pins. * Use multiple vias to connect the power planes to internal layers. 26 Figure 42. Typical Top-Layer Layout Figure 43. Typical Layer-2 Layout Figure 44. Typical Layer-3 Layout Figure 45. Typical Bottom-Layer Layout Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 9.24 EMI The LMZ31707 is compliant with EN55022 Class B radiated emissions. Figure 46 and Figure 47 show typical examples of radiated emissions plots for the LMZ31707 operating from 5V and 12V respectively. Both graphs include the plots of the antenna in the horizontal and vertical positions. Figure 46. Radiated Emissions 5-V Input, 1.8-V Output, 7-A Load (EN55022 Class B) Figure 47. Radiated Emissions 12-V Input, 1.8-V Output, 7A Load (EN55022 Class B) Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 27 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 10 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision B (June 2017) to Revision C Page * Added WEBENCH(R) design links for the LMZ31707.............................................................................................................. 1 * Increased the peak reflow temperature and maximum number of reflows to JEDEC specifications for improved manufacturability..................................................................................................................................................................... 2 * Added Device Support section ............................................................................................................................................. 29 * Added Mechanical, Packaging, and Orderable Information section .................................................................................... 30 Changes from Revision A (August 2013) to Revision B * 28 Page Added peak reflow and maximum number of reflows information ........................................................................................ 2 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 11 Device and Documentation Support 11.1 Device Support 11.1.1 Development Support 11.1.1.1 Custom Design With WEBENCH(R) Tools Click here to create a custom design using the LMZ31707 device with the WEBENCH(R) Power Designer. 1. Start by entering the input voltage (VIN), output voltage (VOUT), and output current (IOUT) requirements. 2. Optimize the design for key parameters such as efficiency, footprint, and cost using the optimizer dial. 3. Compare the generated design with other possible solutions from Texas Instruments. The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time pricing and component availability. In most cases, these actions are available: * Run electrical simulations to see important waveforms and circuit performance * Run thermal simulations to understand board thermal performance * Export customized schematic and layout into popular CAD formats * Print PDF reports for the design, and share the design with colleagues Get more information about WEBENCH tools at www.ti.com/WEBENCH. 11.2 Documentation Support 11.2.1 Related Documentation For related documentation see the following: Soldering Requirements for BQFN Packages 11.3 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.4 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2ETM Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.5 Trademarks Eco-mode, E2E are trademarks of Texas Instruments. WEBENCH is a registered trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.6 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 29 LMZ31707 SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 www.ti.com 11.7 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 12.1 Tape and Reel Information REEL DIMENSIONS TAPE DIMENSIONS K0 P1 B0 W Reel Diameter Cavity A0 B0 K0 W P1 A0 Dimension designed to accommodate the component width Dimension designed to accommodate the component length Dimension designed to accommodate the component thickness Overall width of the carrier tape Pitch between successive cavity centers Reel Width (W1) QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE Sprocket Holes Q1 Q2 Q1 Q2 Q3 Q4 Q3 Q4 User Direction of Feed Pocket Quadrants 30 Device Package Type Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W1 (mm) A0 (mm) B0 (mm) K0 (mm) P1 (mm) W (mm) Pin1 Quadrant LMZ31707RVQR B3QFN RVQ 42 500 330.0 24.4 10.35 10.35 4.6 16.0 24.0 Q2 LMZ31707RVQT B3QFN RVQ 42 250 330.0 24.4 10.35 10.35 4.6 16.0 24.0 Q2 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 LMZ31707 www.ti.com SLVSBV7C - JUNE 2013 - REVISED APRIL 2018 TAPE AND REEL BOX DIMENSIONS Width (mm) W L H Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMZ31707RVQR B3QFN RVQ 42 500 383.0 353.0 58.0 LMZ31707RVQT B3QFN RVQ 42 250 383.0 353.0 58.0 Submit Documentation Feedback Copyright (c) 2013-2018, Texas Instruments Incorporated Product Folder Links: LMZ31707 31 PACKAGE OPTION ADDENDUM www.ti.com 6-Jun-2018 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (C) Device Marking (4/5) LMZ31707RVQR ACTIVE B3QFN RVQ 42 500 RoHS (In Work) & Green (In Work) CU NIPDAU Level-3-245C-168 HR -40 to 85 (54020, LMZ31707) LMZ31707RVQT ACTIVE B3QFN RVQ 42 250 RoHS (In Work) & Green (In Work) CU NIPDAU Level-3-245C-168 HR -40 to 85 (54020, LMZ31707) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. 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