DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger General Description Features The AAT4621 SmartSwitch family is a current limited P-channel MOSFET power switch designed for high-side load-switching applications in PC Card GSM/GPRS/3G modem cards. Used in conjunction with a super capacitor, the AAT4621 will ensure that the power ratings of the PCMCIA host are not exceeded at any time. Featuring two independent, programmable current limits and a power loop, the AAT4621 can ensure that the super capacitor can be charged without exceeding PCMCIA specifications. The current limit is set by two external resistors allowing a 10% current limit accuracy over the normal operating temperature range. The switch can be controlled from either of the two enable inputs and in the off condition will block currents in both directions. The AAT4621 also incorporates a System READY function which can advise the system that the super capacitor is fully charged and ready for use. Adjustable hysteresis is provided with the addition of an external resistor. The quiescent supply current is typically a low 40A. In shutdown mode, the supply current decreases to less than 1A. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current limit range from 150mA to 2400mA. * Operating Voltage Range: 3.0V to 5.5V * Dual Independent Current Limits AAT4621: 75mA to 1200mA AAT4621-1: 150mA to 2400mA 10% Current Accuracy * Reverse Current Blocking Protection * Power Loop * Low Quiescent Current 40A Typical 1.0A Max with Switch Off * 65m Typical RDS(ON) at 3V * System READY Output with Externally Programmable Hysteresis * Only 1.4V Needed for Enable Control Pin * Under-Voltage Lockout * Over-Temperature Protection * Temperature Range: -40 to 85C * 14-Pin TDFN33 Package The AAT4621 is available in a thermally enhanced, Pb-free 14-pin TDFN33 package and is specified over the -40C to 85C temperature range. Applications * * * * * Capacitor Charger CF Card Port Power Protection Express Card GSM/GPRS/3G Modems PC Card GSM/GPRS Class 10/12 Modems WiMAX Cards Typical Application 100k Reverse Blocking VCC OUT To Load RDY To C VCC Over-Temp Protection Power Loop UnderVoltage Lockout EN IL ENIL ENIU EN IU 1.2V Reference Current Limit Control ISETL ISETU GND SuperCap R HYS R SETU R SETL Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 1 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Pin Descriptions Pin # Symbol 1 2 RDY RHYS 3 ISETU 4 ISETL 5, 6, 7 8, 9, 10, 11 12 OUT VCC GND 13 EN IL 14 EN IU EP EP Function System ready pin. Open drain, active low, initiated when the capacitor is 98% charged. System READY hysteresis. Connect a resistor to ground to set the System Ready comparator hysteresis. Upper current limit set input. A resistor from ISETL to ground sets the maximum upper current limit for the switch. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current limit range from 150mA to 2400mA. Connect to ground to disable current limit. Lower current-limit set input. A resistor from ISETU to ground sets the maximum lower current limit for the switch. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current limit range from 150mA to 2400mA. Connect to ground to disable current limit. P-channel MOSFET drain connection. Connect to super capacitor from OUT to GND. Input pins to the P-channel MOSFET source. Connect 1F capacitor from VCC to GND. Device ground connection. Enable input. Active low enable with internal pull up. Also switches in the lower current limit initiating the super capacitor to start charging. Enable input. Active low enable with internal pull up. Also switches in the higher current limit to allow the System to start functioning. Can be directly connected to System Ready for automatic enabling. When both EN IL B and EN IU B are enabled, ISETU will be selected. The exposed thermal pad (EP) must be connected to the board ground plane and Pin 12. The ground plane should include a large exposed copper pad under the package for thermal dissipation (see package outline). Pin Configuration TDFN33-14 (Top View) RDY RHYS ISETU ISETL OUT OUT OUT 2 1 14 2 13 3 4 12 EP 11 5 10 6 9 7 8 ENIU ENIL GND VCC VCC VCC VCC Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Absolute Maximum Ratings1 Symbol Description VCC VEN VSET, VOUT IMAX TJ TLEAD TSTG VCC to GND ENIL, ENIU to GND ISETL, ISETU, OUT to GND Maximum Continuous Switch Current Maximum Junction Operating Temperature Range Maximum Soldering Temperature (at leads, 10 sec.) Storage Temperature Range Value Units -0.3 to 6.0 -0.3 to VCC + 0.3 -0.3 to VCC + 0.3 2.5 -40 to +150 300 -65 to 150 V V V A C C C Value Units 50 2 C/W W Thermal Characteristics Symbol JA PD Description Maximum Thermal Resistance2 Maximum Power Dissipation2 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 board. Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 3 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Electrical Characteristics1 VCC = 3.0V to 5.5V, TA = -40C to 85C unless otherwise noted. Typical values are at TA = 25C. Symbol AAT4621 VCC IQ IQU0 Description Operation Voltage Quiescent Current Quiescent Current U0 IQ(OFF) ISD(OFF) VUVLO Off Supply Current Off Switch Current Under-Voltage Lockout RDS(ON) On-Resistance ILIMACC Lower Current Limit Accuracy ILIMACC Upper Current Limit Accuracy ILIM(MIN) VEN(L) VEN(H) IEN(SINK) TDEL(OFF) VRDY VRDYHYS VRDY(L) IRDY OTMP Minimum Current Limit EN Input Low Voltage EN Input High Voltage EN Input Leakage Turn-Off Delay Time System READY Trip Threshold System READY Hysteresis System READY Voltage Low RDY Leakage Current Shutdown Temperature Conditions Min Typ Max Units 40 5.5 75 V A 40 75 A 0.4 0.4 2.7 50 65 200 200 1000 1000 75 1.0 10 3.0 100 120 220 230 1100 1150 A A V 3.0 EN IL or EN IU = VCC, IOUT = 0, RHYS = 200k EN IL = VCC, EN IU = GND, IOUT = 0, ISET = GND, RHYS = 200k EN IL = EN IU = VCC EN IL = EN IU = VCC, VSUPERCAP = 0 Rising edge, 1% hysteresis VCC = 4.75V, RSETL = RSETU = 0k VCC = 3.0V, RSETL = RSETU = 0k RSETL = 249K; TA 25C RSETL = 249K RSETU = 1.24M; TA 25C RSETU = 1.24M VCC = 3.0V to 5.5V2 VCC = 3.0V to 5.5V2 VEN = 5.5V VCC = 5V VOUT rising, TA = 25C RHYS = 200k ISINK = 1mA VRDY < 5.5V, VOUT < 98% of VOUT 180 170 900 850 0.4 1.4 0.4 98 200 1.0 1.0 0.4 1.0 145 m mA mA mA V V A s % of VOUT mV V A C 1. The AAT4621 is guaranteed to meet performance specification over the -40C to 85C operating temperature range and is assured by design, characterization and correlation with statistical process controls. 2. For VCC outside this range consult the Typical EN Threshold curve. 4 Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Electrical Characteristics1 VCC = 3.0V to 5.5V, TA = -40C to 85C unless otherwise noted. Typical values are at TA = 25C. Symbol Description AAT4621-1 VCC Operation Voltage IQ Quiescent Current IQ(OFF) Off Supply Current ISD(OFF) Off Switch Current Under-Voltage Lockout VUVLO Hysteresis RDS(ON) On-Resistance ILIMACC Lower Current Limit Accuracy ILIMACC Upper Current Limit Accuracy ILIM(MIN) Minimum Current Limit EN Input Low Voltage, VENLU EN Input Low Voltage, VENLL EN Input High Voltage, VENHU EN Input High Voltage, VENHL EN Input Leakage Turn-Off Delay Time System Ready Trip Threshold System Ready Hysteresis System Ready Voltage Low RDY_ Leakage Current VEN(L) VEN(H) IEN(SINK) TDEL(OFF) VRDY VRDYHYS VRDY(L) IRDY OTMP Shutdown Temperature Conditions Min Typ Max Units 5.5 75 1 10 3 V A A A V mV 3 ENIL or ENIU = 0V, IOUT = 0; RHYS = 200k ENIL = ENIU = High, VOUT = Open ENIL = ENIU = High, VOUT = 0V Rising Edge VCC = 4.75V, RSETU = RSETL = 0K VCC = 3.0V, RSETU = RSETL = 0K RSETL = 249K; TA 25C RSETL = 249K RSETU = 1.24M; TA 20C, RSETU = 1.24M , VCC = 3.0 to 5.5V VCC = 3.0 to 5.5V VCC = 3.0 to 5.5V VCC = 3.0 to 5.5V VEN = 5.5V VCC = 5.0V VOUT Rising, TA = 25C (VIN = 3.3V) RHYS = 200K ISINK = 1mA VRDY < 5.5V, VOUT < 98% Of VOUT Thermal Shutdown Temperature Thermal Shutdown Hysteresis 360 340 1800 1700 40 0.4 0.4 2.7 120 50 65 400 400 2000 2000 150 100 120 440 460 2200 2300 0.4 0.4 1.4 1.4 0.4 98 200 1 1 0.4 1 150 15 m mA mA mA V V V V A s % of VOUT mV V A C 1. The AAT4621 is guaranteed to meet performance specification over the -40C to 85C operating temperature range and is assured by design, characterization and correlation with statistical process controls. Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 5 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Typical Characteristics AAT4621 Output Current vs. Output Voltage (RSETU = 383k, 25C) AAT4621-1 Output Current vs. Output Voltage (RSETU = 374K; TA = 25C) 0.7 VCC = 3.3V Output Current (A) Output Current (A) 0.40 0.30 0.20 VCC = 5V 0.10 0.6 0.5 0.3 0.2 0.1 0 0.00 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 1.5 3.3 1.8 2.1 2.4 Output Voltage (V) 3.3 3.6 3.9 4.2 4.5 4.8 5.1 (25C) 1.40 3 1.20 2.5 2 VCC = 3.3V ILIM (A) ILIM (A) 3.0 AAT4621-1 ILIM vs. RSET (25C) 1.00 2.7 Output Voltage (V) AAT4621 ILIM vs. RSET 0.80 0.60 VCC = 3.3V 1.5 1 VCC = 5V 0.40 VCC = 5V 0.5 0.20 0 0.00 0 200 400 600 800 1000 1200 1400 1600 0 200 400 600 800 1000 1200 1400 1600 RSET (k) RSET (k) Reverse Off-Switch Current vs. Temperature Off-Switch Current vs. Temperature (ENIU = ENIL = High; VCC = 0V) (ENIU = ENIL = High; VOUT = 0V) 100 100 10 10 VOUT = 5V ISD(OFF) (A) IRSD(OFF) (A) VCC = 5V VCC = 3.3V 0.4 1 0.1 VOUT = 3.3V VCC = 5V 1 0.1 VCC = 3.3V 0.01 -40 -20 0 20 40 60 Temperature (C) 6 80 100 120 0.01 -40 -20 0 20 40 60 80 Temperature (C) Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 100 120 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Typical Characteristics Off-Supply Current vs. Temperature RDS(ON) vs. Input Voltage (ENIU = ENIL = VCC; VOUT = Open) (RSET = 0k ) 10 70 65 RDS(ON) (m) IQ(OFF) (A) VCC = 5V 1 0.1 VCC = 3.3V 0.01 -40 -20 0 20 40 60 80 100 60 55 50 45 2.5 120 3 3.5 4 4.5 Temperature (C) Input Voltage (V) RDS(ON) vs. Temperature VRHYS vs. RRHYS (RSET = 0) 5 5.5 2.00 90 1.80 1.60 VCC = 3V 1.40 70 VRHYS (V) RDS(ON) (m) 80 60 50 1.20 1.00 0.80 0.60 0.40 VCC = 5V 40 30 -40 0.20 0.00 -20 0 20 40 60 80 0 100 500 Temperature (C) 1000 1500 RRHYS (k) AAT4621 ILIM vs. Temperature AAT4621 ILIM vs. Temperature (VCC = 4V; VOUT = 3.85V; ENIL = 0V; RSETL = 249k) (VCC = 4V; VOUT = 3.85V; ENIU = 0V; RSETU = 1.3M) 205 1020 1010 1000 ILIM (mA) ILIM (mA) 200 195 990 980 970 190 960 185 -50 -25 0 25 50 Temperature (C) 75 100 950 -50 -25 0 25 50 75 100 Temperature (C) Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 7 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Typical Characteristics AAT4621-1 ILIM vs. Temperature AAT4621-1 ILIM vs. Temperature (VCC = 5V; VOUT = 4.5V; ENIL = 0V; RSETL = 249k) (VCC = 5V; VOUT = 4.5V; ENIU = 0V; RSETU = 1.24M) 2100 420 2080 2060 ILIM (mA) ILIM (mA) 415 410 405 2040 2020 2000 1980 400 1960 1940 395 -50 -25 0 25 50 75 100 -50 -25 Temperature (C) 75 (ENIU = Open; Vary ENIL; T = 25C) VEN(H) 1.0 VIH and VIL (V) VCC = 5V 45 40 35 0.9 0.8 VEN(L) 0.7 30 VCC = 3.3V -20 0 20 40 60 80 100 120 Temperature (C) 0.6 2.5 3.5 4.5 5.5 6.5 Input Voltage (V) VEN(H) and VEN(L) vs. Input Voltage (ENIL = Open; Vary ENIU; T = 25C) VEN(H) and VEN(L) (V) 1.1 VEN(H) 1.0 0.9 0.8 VEN(L) 0.7 0.6 2.5 3.5 4.5 5.5 6.5 7.5 Input Voltage (V) 8 100 1.1 55 IQ (A) 50 VEN(H) and VEN(L) vs. Input Voltage (ENIU = 0V; ENIL = VCC; or ENIL = 0V; ENIU = VCC; VOUT = Open) 25 -40 25 Temperature (C) Quiescent Current IQ vs. Temperature 50 0 Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 7.5 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Typical Characteristics Hard Short Circuit Hard Short Circuit 2 VOUT 0 1.5 1.0 IOUT 0.5 0.0 6 VCC 4 2 VOUT 0 1.5 1.0 IOUT 0.0 Time (20ms/div) Time (20ms/div) Soft Short Circuit with 5 Series Impedance Soft Short Circuit with 5 Series Impedance (VCC = 5V) 6 5 5 0.6 IOUT 0.4 0.2 0.0 Time (2ms/div) Charging Profile 0.8 I OUT 0.6 0.4 0.2 0.0 Charging Profile (ILIMIT = 1A; VCC = 4.5V; CO = 0.55F) 6 6 VOUT 0 0.15 0.10 I OUT 0.05 0.00 Time (5s/div) 2 Thermal Foldback VOUT 1.0 0.8 0 0.6 0.4 IOUT 0.2 0.0 Output Current (A) 2 Output Voltage (V) 4 Output Current (A) Output Voltage (V) 1.0 4 Time (2ms/div) (ILIMIT = 150mA; VCC = 4.5V; CO = 0.55F) 4 VCC and VOUT Output Current (A) VCC and VOUT 3 Input Voltage (V) Output Voltage (V) 6 Output Current (A) Input Voltage (V) Output Voltage (V) (VCC = 3.3V) 4 0.5 Output Current (bottom) (A) VCC 4 Input Voltage (top) (V) Output Voltage (middle) (V) (VCC = 5V) Output Current (bottom) (A) Input Voltage (top) (V) Output Voltage (middle) (V) (VCC = 3.3V) Time (1s/div) Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 9 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Typical Characteristics 2.0 1.5 1.0 I OUT 0.5 0.0 -0.5 Input Voltage (top) (V) Output Voltage (middle) (V) VOUT = 3.80V VCC = 3.83V VOUT = 3.76V 2.0 1.5 1.0 I OUT 0.5 0.0 -0.5 Time (1ms/div) Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 Output Current (bottom) (A) VCC = 3.83V Time (1ms/div) 10 GSM900 GPRS Class 12 Transmit 2-Slot Ch975, 33dBm Output Current (bottom) (A) Input Voltage (top) (V) Output Voltage (middle) (V) GSM900 GPRS Class 12 Transmit 1-Slot Ch975, 33dBm DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Functional Block Diagram Reverse Blocking OUT VCC Over-Temp Protection Power Loop UnderVoltage Lockout RDY EN IL EN IU 1.2V Reference Current Limit Control GND Functional Description The AAT4621 SmartSwitch family is an integrated P-channel MOSFET load switch with an upper and lower adjustable current limits which can be enabled independently, over temperature protection, a power loop and a super capacitor charger. The current limit control is combined with an over temperature thermal limit and power loop circuit to provide a comprehensive system to protect the load switch and its supply from load conditions which exceed the supply specifications. The AAT4621 has been designed specifically to provide the interface between a PCMCIA host and PC card where a super capacitor has been used to "average out" high pulse currents which would otherwise exceed the PCMCIA/ Express Card power specifications. e.g. GSM/ GPRS modem cards, where pulse currents during transmit signals can exceed the 1A maximum specification (1.3A in the case of Express Card). The current limit and over temperature circuits act independently. The device current limit is activated when the output load current exceeds an internal threshold level. There are two internal current limits which are enabled independently. The current limit threshold in each case is determined by external resistors connected between the two SET pins and ground. The minimum current limit ISETL ISETU RHYS threshold is specified by ILIM(MIN). If the load condition maintains the device in current limit and the chip temperature reaches a critical point, then an internal power loop will reduce the current to a safe level. Connecting ISETU to ground disables the current limit protection allowing a low impedance path to the host VCC. The load switch is turned off by applying a logic high level to both of the EN pins. When both EN IL and EN IU are selected ISETU will be selected. The EN function has logic level thresholds that allow the AAT4621 to be TTL compatible and may also be controlled by 2.5V to 5.0V CMOS circuits. The voltage level applied to the EN pins should not exceed the input supply level present on the VCC pin. The AAT4621 typically consumes 40A when operating, when off, the device draws less then 1A. In the off state, current is prevented from flowing between the input and output. Under-voltage lockout circuitry ensures that the VCC supply is high enough for correct operation of the IC. Also included is a System Ready function which will be activated when the capacitor voltage is charged and the load is permitted to take current. For automatic functionality, this pin can be directly connected to the EN IU pin. An external resistor is provided to add hysteresis to this function. Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 11 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Application Information ISETU and ISETL Current Limit Set The AAT4621/AAT621-1 current limit is set at two different levels. Resistors from ISETL and ISETU set the lower and upper current limit levels respectively. The ISETL and ISETU nodes operate within a window of 0.75V to 1.5V for resistor values ranging from 93.75 to 1.5M. Resistor values outside this range are not recommended. The ISETL and ISETU source current varies with the resistor value used according to Table 1. To determine the resulting current limit multiply the RSETU or RSETL node voltage times the gain in Table 1. Note that the voltage at the node varies from 0.75V to 1.5V and the current limit gain varies depending on the resistor value used. VISET = RSET * IISET = 0.75V to 1.5V If the set pin is open circuit or allowed to exceed 2V, all power devices are disabled and the input is disconnected from the output. Shorting the set pin to GND enables all power devices and shorts the VCC to the output pin with no current limit. To activate the upper current level (RSETU) pull EN IU low. To activate the lower current level (RSETL) pull EN IL low. If both EN IU and EN IL are pulled low the EN IU current limit level (RSETU) will be selected. The AAT4621 has a current limit range from 75mA to 1200mA; the AAT4621-1 has a current limit range from 150mA to 2400mA. ILIM/VISET (A/V) Current Limit (mA) 3000 2500 2000 AAT4621-1 1500 1000 500 AAT4621 0 100 300 500 700 900 1100 1500 1300 RSETU and RSETL () Figure 1: Calculated Current Limit RSET Characteristic. System Ready Hysteresis (RHYS) and System Ready (RDY) In internal comparator senses the output voltage and delivers a ready signal to the external micro controller when the output voltage reaches 98% of the final value (VCC). The comparator hysteresis is programmed by a resistor from the RHYS pin to ground. The RHYS voltage determines the hysteresis voltage and is equal to the RHYS source current (1A) times the RHYS resistance. VHYST = RHYS * 1A = 200k * 1A = 0.2V The system ready pin (RDY) is an open drain output that switches low when the output voltage reaches 98% of the input voltage. It requires an external pull up resistor tied to the input voltage with a typical value of 100k. Current Limit Range (A) Current Limit (A) RSET Range () IISET (A) AAT4621 AAT4621_1 AAT4621 AAT4621_1 AAT4621 AAT4621_1 1.5Meg -750K 750K -375K 375K -187.5K 187.5K-93.75K 1 2 4 8 0.8 0.4 0.2 0.1 1.6 0.8 0.4 0.2 1.2-0.6 0.6-0.3 0.3-0.15 0.15-0.075 2.4 - 1.2 1.2 - 0.6 0.6 -0.3 0.3 - 0.15 RSET*1*0.8 RSET*2*0.4 RSET*4*0.2 RSET*8*0.1 RSET*1*1.6 RSET*2*0.8 RSET*4*0.4 RSET*8*0.2 Table 1: RSET Table. 12 Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Power Loop Over-Temperature Protection The AAT4621 power loop limits the load current in the event that the device power dissipation becomes excessive. The AAT4621 power loop regulates the die temperature to 110C (or 130C for the AAT4621-1), decreasing the load current in increments of 1/32 of the current limit set point when the die temperature reaches 110C (or 130C for the AAT4621-1). When the die temperature exceeds 110C (or 130C for the AAT4621-1) it decreases the load current by 1/32 of the current limit set point. If die temperature is less than 110C (or 130C for the AAT4621-1), it increases the load current in increments of 1/32 of the current limit set point until the set current limit point is reached or the die temperature exceeds 110C (or 130C for the AAT4621-1). If the die temperature rate of rise is fast enough to exceed the power loop regulated temperature, overtemperature shutdown disables the device. The overtemperature threshold is 145C (or 150C for the AAT4621-1). After over-temperature shutdown, soft start is initiated once the die temperature drops to 130C (or 135C for the AAT4621-1). The delay time between die temperature measurements varies depending on the load current limit set point. The delay ranges from 0.5ms for a 75mA (or 150mA for the AAT4621-1) current limit set point to 4ms for a 1.2A (or 2.4A for the AAT4621-1) current limit set point. For the condition where there is no current limit set point (shorting RSETU or RSETL to ground) the soft start increments the current limit is 1/32 steps of 1.2A (or 2.4A for the AAT4621-1) until the current reaches 1.2A (or 2.4A for the AAT4621-1), at which point the power MOSFET turns on fully. At this point, the current is limited by the RDS(ON) of the power MOSFET and other series resistance. The Power Loop and Over-Temperature Loop then takes control to limit the current until the output voltage has fully charged. Short Circuit Protection The series pass power MOSFET turns off completely after the output has charged to within 18mV of the input voltage. This protects the device in the event where a short circuit is applied to the output. After applying a short circuit or heavy load to the output, which causes the output to sink below the 18mV threshold plus some hysteresis, the current will immediately attempt to slew from zero to the final programmed value. The device will continue to output the current limit as long as the output is VIN - 18mV or until the die temperature reaches 110C. If temperature fold-back occurs, then the power loop will become active. Under-Voltage Shutdown Under-voltage lockout enables the device at 2.7V typical with 120mV of hysteresis. The maximum UVLO level is 3.0V. Digitally Programmed Soft Start Current Limit At turn on, the digital soft start increases the load current in discrete levels equal to 1/32 of the final programmed current limit set point from zero to the final programmed current limit level. Once the AAT4621 has fully charged the supercap, the soft start circuit is disabled. The soft start function will only reactivate under the following conditions: 1. 2. 3. 4. The power source or enable is cycled off and back on The thermal shutdown is activated Switching from ENIU to ENIL or vice versa Following an over-current event. Reverse Current Blocking An internal comparator disables the internal pass transistor when the input voltage is less than the output voltage blocking any reverse current from the output to the input. Evaluation Board The AAT4621/AAT4621-1 evaluation board schematic is shown in Figure 2. The AAT4621/AAT4621-1 PCB layout is shown in Figures 3 and 4. Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 13 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Layout Guidance 2. When laying out the PC board, the following layout guideline should be followed to ensure proper operation of the AAT4621/AAT4621-1: 3. 1. The exposed pad EP must be reliably soldered to GND. The exposed thermal pad should be connected to the board ground plane and Pin 12. The ground plane should include a large exposed copper pad under the package with VIAs to all board layers for thermal dissipation. J1 VCC VCC EN IU EN IU R1 1.5K The power traces, including GND traces and the VCC trace should be kept short, direct and wide to allow large current flow. Use several via pads when routing between layers. The input capacitors (C1) should be connected as close as possible to VCC (Pins 8, 9, 10, 11) and GND (Pin 12) to get good power filtering. The output capacitor (C2) should be connected as close as possible to OUT (Pins 5, 6, 7) and GND (Pin 12) to get good power filtering as the device will recharge the Supercap when the output voltage level sensed on the OUT pin is reduced by approximately 18-20mV below its input voltage (VCC) level. 4. D1 P1 RDY LED RED RDY U1 J2 VCC 14 EN IL EN IL 13 12 VCC P2 VCC P4 GND 11 TB1 C1 10F 10 9 IN 8 EN IU RDY EN IL RHYS GND ISETU VCC ISETL VCC OUT VCC OUT VCC OUT AAT4621/AAT4621-1 1 2 RHYS 3 ISETU 4 ISETL R2 200K R3 1M 5 6 R4 120K P3 OUT 7 C2 10F + OUT R5 47.5K + SC1 0.55F R6 47.5K TB 2 OUT P5 GND Figure 2: AAT4621/AAT4621-1 Evaluation Board Schematic. Figure 3: AAT4621/AAT4621-1 Evaluation Board PCB Top Side. 14 Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Figure 4: AAT4621/AAT4621-1 Evaluation Board PCB Bottom Side. Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 15 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Ordering Information Package Marking1 Part Number (Tape and Reel)2 TDFN33-14 TDFN33-14 YWXYY K5XYY AAT4621IWO-T1 AAT4621IWO-1-T1 Skyworks GreenTM products are compliant with all applicable legislation and are halogen-free. For additional information, refer to Skyworks Definition of GreenTM, document number SQ04-0074. Package Information3 TDFN33-14 Detail "A" 3.000 0.050 2.500 0.050 Index Area 3.000 0.050 1.650 0.050 Top View Bottom View + 0.100 - 0.000 Pin 1 Indicator (Optional) 0.180 0.050 Side View 0.400 BSC 0.000 0.203 REF 0.750 0.050 0.425 0.050 Detail "A" All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required to ensure a proper bottom solder connection. 16 Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 DATA SHEET AAT4621 PC Card Current Limit Interface and Capacitor Charger Copyright (c) 2012 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. ("Skyworks") products or services. These materials, including the information contained herein, are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. 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Skyworks assumes no liability for applications assistance, customer product design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters. Skyworks, the Skyworks symbol, and "Breakthrough Simplicity" are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference. Skyworks Solutions, Inc. * Phone [781] 376-3000 * Fax [781] 376-3100 * sales@skyworksinc.com * www.skyworksinc.com 201944A * Skyworks Proprietary Information * Products and Product Information are Subject to Change Without Notice. * May 15, 2012 17