DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger General Description Features The AAT4712 is a programmed, current limited P-channel MOSFET power switch designed for high-side load-switching applications for SSD memory buffer saving solutions. With the programmed current limit, the AAT4712 ensures that the power ratings of the host are not exceeded and balances the system load and supercap charging current automatically to provide enough system load current in top-priority. The integrated discharge path control assures that the system load can still be supported in the short term when the input power has not fully charged the supercap. The current limit is programmed by an external resistor allowing ±10% accuracy at room temperature. •VCC Range: 2.5V – 5.5V • Input Current Limits: ▪ 150mA - 2400mA ▪ ±10% Current Accuracy at 2A Input Current Limit Setting •Low Quiescent Current: ▪ 70µA Typical (VCC Input) ▪ 12µA Typical (OUT Input) • Under-Voltage Lockout • Integrated Discharge Path for SYS (to System Load) from VCC Input or OUT Input (Connect to Supercap) • Maximum 100mΩ RDS(ON) from OUT to SYS at 5V VCC • Reverse Blocking Protection • Power Loop Current Reduction • Over-Temperature Protection • SYS Short Circuit Protection • Input Power Good Detect Threshold Setting (ADJ) • Input Power Good Indicate (POK) • Supercap Charge Ready (RDY) Output • Temperature Range: -40 to 85°C • 16-Pin TDFN34 Package The AAT4712 integrates discharge path for SYS (to system load) from VCC input or OUT input (connect to supercap). The low RDS(ON) from OUT to SYS prolongs the supercap backup time when VCC drops below a threshold voltage which is programmed by an external resistor from ADJ to ground. The AAT4712 incorporates a POK function which can indicate system input power good. An ADJ pin is provided with the addition of an external resistor for setting the input power good detect threshold. The AAT4712 also incorporates a supercap charge ready (RDY) indicate function. The quiescent supply current is typically a low 70µA from the discharge path of VCC to SYS. Applications •SSD The AAT4712 is available in a 16-pin TDFN34 package and is specified over a -40 to 85°C temperature range. Typical Application VIO VSYS VCC 2.5V - 5.5V VCC ADJ CIN 10µF SYS AAT4712 ISET RADJ RDY RDY POK POK OUT RSET GND CSYS 10µF Super Capacitor Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 1 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Pin Descriptions Pin # Symbol 1 RDY 2 ISET 3 4, 5, 6, 7, 8 9, 10, 11 12, 13 14 15 16 N/C SYS OUT VCC ADJ GND POK Function Supercap charge ready output, initiated when the capacitor is 98% charged. Open drain, active high. Input current-limit set input. A resistor from ISET to ground is necessary and sets the maximum current limit for the switch. The current limit can be programmed from 150mA to 2000mA. No connect. System power output supplied from the VCC input or OUT input. Connect to super capacitor from OUT to GND. Input pins to the P-channel MOSFET source. Connect a 10µF capacitor from VCC to GND. Input power good detect threshold. An internal 50kΩ resistor is integrated between ADJ and VCC. Device ground connection. Input power good indicator. Push pull, active high. Pin Configuration TDFN34-16 (Top View) RDY ISET N/C SYS SYS SYS SYS SYS 2 1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 POK GND ADJ VCC VCC OUT OUT OUT Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Absolute Maximum Ratings1 Symbol VP VRDY, VPOK , VADJ VISET, VSYS IMAX TJ TSTG TLEAD Description VCC, OUT to GND RDY, POK, ADJ to GND ISET, SYS to GND Maximum Continuous Switch Current Operating Junction Temperature Range Storage Temperature Maximum Soldering Temperature (at Leads) Value Units -0.3 to 6 -0.3 to VP + 0.3 -0.3 to VP + 0.3 2.5 -40 to 150 -40 to 150 300 V V V A °C °C °C Value Units 50 2 °C/W W Thermal Characteristics2 Symbol ΘJA PD Description Maximum Thermal Resistance3 Maximum Power Dissipation3 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 a FR4 board. 3. Derate 50mW/°C above 25°C. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 3 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Electrical Characteristics1 VCC = 2.5V to 5.5V, TA = -40°C to 85°C unless otherwise noted. Typical values are at TA = 25°C Symbol VCC IQ Description IOUT_OP Normal Operation Voltage VCC Quiescent Current OUT Operating Current VUVLO_VCC VCC Under-Voltage Lockout VUVLO_OUT OUT Under-Voltage Lockout RDS(ON)_SWA VCC to SYS On-Resistance RDS(ON)_SWB VCC to OUT On-Resistance RDS(ON)_SWC ILIMHACC ILIM(MIN) TRESP TDEL(OFF) OUT to SYS On-Resistance Input High Current Limit Accuracy Minimum Input Current Limit Current Limit Response Time Turn-Off Delay Time TSW OUT to SYS Switch Turn On Response Time VADJ ADJ Pin Voltage with Trigger Comparator TDETECT ADJ Pin Detect Delay Time VPOK(L) Output Low Voltage VPOK(H) Conditions Min Typ 2.5 IOUT = 0, No Load at SYS Pin VOUT = 5V, VCC = GND, No Load at SYS Pin Falling Edge Hysteresis Falling Edge Hysteresis VCC = 5V, RSET = 1.24MΩ, ILOAD = 600mA VCC = 3.3V, RSET = 1.24MΩ, ILOAD = 600mA VCC = 5V, RSET = 1.24MΩ, ILOAD = 600mA VCC = 3.3V, RSET = 1.24MΩ, ILOAD = 600mA VOUT = 3V ~ 5V RSET = 1.24MΩ, TA = 25°C 70 12 2.1 150 1.8 250 50 65 140 160 1800 VCC = 5V, RSET = 1.24MΩ VCC = 5V VCC Voltage Step-Down Signal from 5V to 4.5V ADJ Voltage Step Down Signal from 1.3V to 1.1V ADJ ≤ 1.2V Output High Voltage ADJ > 1.2V VRDY Supercap Charge Ready Trip Threshold VOUT Rising, TA = 25°C VRDYSYS VRDY(L) OTMP THYS Supercap Charge Ready Hysteresis RDY Output Low Voltage Shutdown Temperature Over-Temperature Shutdown Hysteresis 2000 150 2 0.4 Max Units 5.5 120 30 2.4 V µA µA V mV V mV 2 100 120 300 320 100 2200 10 mΩ mΩ mΩ mA mA µs µs 6 µs 1.2 V 2 µs 0.4 0.8 VCC V V 98 200 RDY Pin Sinks 1mA 0.4 150 15 % of VCC mV V °C °C 1. The AAT4712 is guaranteed to meet performance specifications over the -40°C to 85°C operating temperature range and is assured by design, characterization and correlation with statistical process controls. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Typical Characteristics VOUT Quiescent Current vs. Temperature 90 25 80 20 70 15 IQ (µA) IQ (µA) VCC Quiescent Current vs. Temperature 60 VCC = 5.5V VCC = 5.0V VCC = 3.0V VCC = 2.5V 50 40 -40 -15 10 35 10 5 60 0 -40 85 Temperature (°C) 2.26 2.12 2.22 2.06 VUVLO_OUT (V) VUVLO_VCC (V) 2.18 2.18 2.14 2.10 2.06 10 35 60 1.88 1.82 1.64 -40 RDS(ON)_SWC (mΩ) RDS(ON)_SWA (mΩ) 100 68 52 VCC = 3.3V VCC = 5.0V Temperature (°C) 35 60 85 RDS(ON)_SWC vs. Temperature 84 60 10 (Load Current = 600mA, RSET = 1.24MΩ) 120 35 -15 Temperature (°C) 100 10 VOUT Rising VOUT Falling RDS(ON)_SWA vs. Temperature -15 85 1.94 (Load Current = 600mA, RSET = 1.24MΩ) 20 -40 60 2.00 1.70 85 Temperature (°C) 36 35 1.76 VCC Rising VCC Falling -15 10 VUVLO_OUT vs. Temperature 2.30 1.98 -40 -15 Temperature (°C) VUVLO_VCC vs. Temperature 2.02 VOUT = 5.5V VOUT = 5.0V VOUT = 3.0V VOUT = 2.5V 80 60 40 20 -40 85 VOUT = 3.3V VOUT = 5.0V -15 10 35 60 85 Temperature (°C) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 5 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Typical Characteristics RDS(ON) vs. Input Voltage Current Limit Error vs. Temperature (Load Current = 600mA, RSET = 1.24MΩ) (VCC = 5.0V, RSET = 1.24MΩ) 80 4 Current Limit Error (%) RDS(ON)_SWA RDS(ON)_SWC 75 RDS(ON) (mΩ) 70 65 60 55 50 45 40 2.5 3 3.5 4 4.5 5 0 -2 -4 -6 -40 5.5 Input Voltage (V) 2 -15 Current Limit vs. SYS Voltage 2.00 2.00 Current Limit (A) Current Limit (A) 2.50 1.50 1.00 0.50 4.5 4 3.5 3 2.5 2 VSYS (V) 1.5 1.00 0.50 0.00 1 0 200 400 600 800 1000 1200 RSET (kΩ) POK Delay Time (VCC = 5.0V, RSET = 1.24MΩ) (RADJ = 18.2kΩ) VADJ (0.2V/div) VCC (1V/div) VPOK (2V/div) VPOK (2V/div) Time (0.8µs/div) 85 1.50 ADJ Detect Delay Time 6 60 (VCC = 5.0V) 2.50 5 35 Current Limit vs. RSET (RADJ = 18.2kΩ, RSET = 1.24MΩ, CIN = CSYS = 10μF) 0.00 10 Temperature (°C) Time (100µs/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 1400 1600 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Typical Characteristics RDY Delay Time From High to Low RDY Delay Time From Low to High (VCC = 5.0V, RSET = 1.24MΩ) (VCC = 5.0V, RSET = 1.24MΩ) VOUT (1V/div) VOUT (1V/div) VRDY (2V/div) VRDY (2V/div) 4.5 4.5 0 0 Time (2µs/div) Time (100µs/div) Current Limit Response Load Transient (VCC = 5.0V, RSET = 1.24MΩ, RLOAD = 5Ω to 1Ω) (VCC = 5.0V, VOUT = 2.0V, RSET = 1.24MΩ, ISYS = 1A to 2A) VSYS (2V/div) VCC (0.2V/div) ISYS (2A/div) ISYS (2A/div) 0 1 VSYS (1V/div) 4.5 ICC 2 (1A/div) IOUT (2A/div) 0 5 0 Time (20µs/div) Time (10ms/div) Discharge Path Switching (VOUT = 5.0V, RSET = 1.24MΩ, RADJ = 18.2kΩ, VCC = 5V to 4V, 1A Load) VCC (1V/div) ICC (1A/div) IOUT (1A/div) ISYS (1A/div) 4 0 0 1 Time (100ms/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 7 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Functional Block Diagram Reverse Blocking VCC SYS Over-Temp Protection Under Voltage Lockout 1.2V Reference ADJ OUT Current Limit Control RDY Voltage Detector Control System POK GND Functional Description The AAT4712 is an integrated P-channel MOSFET load switch with adjustable current limits, integrated discharge path, over temperature protection, a power loop and a super capacitor charger. The input 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 exceeding the supply specifications. The AAT4712 integrates the discharge path for SYS (to system load) from the VCC input or OUT input (connected to supercap) determined by whether VCC is higher than the programmed threshold setting by ADJ through an external resistor. The input current is limited and is programmed by an external resistor for both system load and supercapacitor charging; system load always has higher priority. The device decreases supercapacitor charging current to provide more current to system load when the system load increases and keeps the host power rating from exceeding the input current limit. 8 Power Loop ISET The integrated over-temperature circuits act independently of the input current limit. The device input current limit is activated when the output load current exceeds an internal threshold level. The input current limit threshold in each case is determined by external resistors connected between the ISET pin and ground. The minimum input current limit 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. VCC pin under-voltage lockout circuitry ensures that the VCC supply is high enough for correct operation of the IC. OUT pin under-voltage lockout circuitry ensures that the VOUT supply is high enough for correct operation of the IC when no VCC input power or VCC below UVLO voltage. An integrated POK function is adopted to indicate the system input power good. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Setting the Input Current Limit Discharge Path Control The AAT4712 current limit is set via the ISET resistor. The ISET node operates within a window of 0.6V to 1.2V for resistor values ranging from 93.75kΩ to 1.5MΩ. Resistor values outside this range are not recommended. The ISET source current varies with the resistor value as shown in Table 1. When the input voltage drops below the power good detect threshold programmed by the external resistor from ADJ pin to GND and the OUT pin voltage is greater than the VUVLO_OUT and SYS pin voltage, the AAT4712 turns on the OUT to SYS switch discharge path after 6µs (TSW) response time, then turns off the path of VCC to the SYS P-channel load switch. The OUT to SYS switch remains continuously on until the OUT pin voltage falls below VUVLO_OUT. VISET = RSET · IISET = 0.6V to 1.2V 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. SYS Load and Capacitor Charge The input current limit is equal to the SYS current plus the OUT charging current. If the SYS current increases/ decreases, the OUT charging current will automatically decrease/increase accordingly by the device control loop. For example, if the input current limit is programmed to 1A and the SYS load current is 0.5A, then the OUT charging current is 0.5A; if the SYS load current increases to 0.8A, the OUT current decreases to 0.2A accordingly; if the SYS load current decreases to 0.2A, the OUT current increases to 0.8A dynamically. Power Loop The AAT4712's power loop limits the load current if device power dissipation becomes excessive. The power loop decreases the load current gradually to 1/32 of the current limit set point when the die temperature exceeds 130°C. The load current then increases in increments of 1/32 of the current limit set point until the set current limit point is reached or the die temperature exceeds 130°C. Figures 1 and 2 show the the power loop function as the device temperature increases and decreases at a 1A current limit setting. RSET Range (Ω) IISET (µA) ILIM/VISET (A/V) Current Limit Range (A) Current Limit 1.5M - 750k 750k - 375k 375k - 187.5k 187.5k - 93.75k 0.8 1.6 3.2 6.4 2 1 0.5 0.25 2.4-1.2 1.2-0.6 0.6-0.3 0.3-0.15 RSET*0.8*2 RSET*1.6*1 RSET*3.2*0.5 RSET*6.4*0.25 Table 1: RSET Values for Setting the Input Current. Increase Ambient Temperature ICC (100mA/div) ICC (100mA/div) Drop to 1/32 of 1A Current Limit 0A 0A Time (20ms/div) Figure 1: AAT4712 Power Loop Function at 1A Current Limit with Ambient Temperature Increasing. Time (20ms/div) Figure 2: AAT4712 Power Loop Function at 1A Current Limit with Ambient Temperature Decreasing. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 9 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Application Information The delay time between die temperature measurements varies depending on the load current limit set point. The delay ranges from 0.5ms for a 150mA current limit set point to 4ms for a 2.4A current limit set point. Over-Temperature Protection If the die temperature rises quickly enough to exceed the power loop regulated temperature, over-temperature shutdown disables the device. The over-temperature threshold is 150°C. After over-temperature shutdown, soft start is initiated once the die temperature drops to 135°C. Input Current Limit Setting The input current limit is programmed by RSET from ISET to ground in the range from 150mA to 2.4A. The current limit limits the maximum current of both VCC to SYS and VCC to OUT. The RSET can be calculated by: RSET = Table 2 lists some 1% standard metal film resistor values for current limit settings from 150mA to 2.4A. RSET (kΩ) Current Limit (A) 1500 1240 1000 750 620 499 374 249 187 93.1 2.4 2 1.6 1.2 1 0.8 0.6 0.4 0.3 0.15 Power OK Indicator (POK) On initial power-up, if VCC is higher than the power good detect threshold programmed by the external resistor from the ADJ pin to GND, the POK signal switches from low to high after 2µs delay time (TDETECT) to indicate input power good. If VCC drops below the power good detect point, the POK signal switches from high to low after 2µs delay time (TDETECT). Capacitor Charge Ready Indicator (RDY) The internal comparator senses the OUT voltage and delivers a high level as ready signal to the external microcontroller when the OUT voltage reaches 98% of the VCC voltage with fixed 200mV hysteresis. The capacitor charge ready pin (RDY) is an open drain output. A external pull up resistor with a typical value of 100kΩ is required. Table 2: Recommended Current Limit RSET Values. Power Good Detect Threshold Setting The power good detect threshold (VPOK_TH) determines the point at which the discharge path changes from VCC – SYS to OUT – SYS if the OUT pin voltage is above VUVLO_ OUT and the SYS pin voltage. The power good detect threshold is programmed by the external resistor RADJ connected from the ADJ pin to GND. The RADJ value can be calculated by: RADJ = 10 ILIM (Current in A, resistance in kΩ) 1.6 60 (Voltage in V, resistance in kΩ) VPOK_TH - 1.2 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Table 3 summarizes some 1% standard metal film resistor values for various VPOK_TH settings. RADJ (kΩ) VPOK_TH (V) 15.8 18.2 20.5 26.1 33.2 47 5.0 4.5 4.0 3.5 3.0 2.5 Table 3: Recommended Resistor Values for VPOK_TH Settings. Discharge Path Control As the AAT4712 powers the system load, the device automatically selects VCC or OUT as the power source. OUT is designed to connect a supercapacitor as a backup source. Figure 3 shows the discharge path control operation at 1A current limit setting. When VCC is powered on from zero to 5V, the SYS voltage also rises to 5V and 500mA current is passed through from VCC to SYS as system load. With the 1A current limit, the additional 500mA is used to charge the supercapacitor via IOUT as shown. After 3.5 seconds, the 550mF supercapacitor is fully charged; the charging current decreases to zero, and ICC current decreases to 500mA. When VCC drops from 5V to zero, the backup power source VOUT provides the 500mA load current to SYS until the supercapacitor voltage is discharged to below the UVLO voltage threshold (typ. 1.8V). VCC (5V/div) VOUT (5V/div) VSYS (5V/div) ISYS (1A/div) ICC (1A/div) IOUT (1A/div) Reverse Blocking The internal reverse blocking comparator disconnects the VCC to SYS path by turning off the power PMOSFETs when SYS is higher than VCC minus 18mV, preventing any reverse current from the system load to the input. With 22mV hysteresis, the VCC to SYS path will be reconnected by turning on the power PMOSFETs when the SYS voltage drops to VIN minus 40mV. The reverse blocking comparator has a typical 5µs delay time, which may lead to output voltage ripple on the SYS output at light load. Increasing the SYS output capacitor value can improve the output voltage ripple when the application has special SYS voltage ripple requirements. Input Capacitor A 10μF capacitor is typically recommended for CIN. CIN should be located as close to the device VCC pin as practically possible. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor equivalent series resistance (ESR) requirement for CIN. However, for higher current operation, ceramic capacitors are recommended for CIN due to their inherent capability over tantalum capacitors to withstand input current surges from low impedance sources. System Output Capacitor A small output capacitance of approximately 10μF is required at the system output. The output capacitor helps to filter the SYS voltage when the device works between reverse blocking and normal operation. For higher output voltage ripple requirements at light load (below 1/3 current limit), a greater output capacitor value is required. OUT Supercapacitor Time (2s/div) Figure 3: Discharge Path Control with 550mF Supercapacitor at 1A Current Limit Setting and 500mA System Load. The AAT4712's OUT pin is designed to connect a supercapacitor to ground to give the system a backup when VCC experiences short power interrupts. A supercapacitor offers high capacitance in a small package; it adopts special electrodes and some electrolyte. Three types of electrode materials are suitable for the supercapacitor: high surface area activated carbons, metal oxide, and conducting polymers. The first option is the lowest cost to manufacture; the electrolyte usually is aqueous or organic. An aqueous electrolyte offers low internal resis- Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 11 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger tance but limits the voltage to 1V; the organic allows 2.5V of charge but has higher internal resistance. For higher voltage applications, supercapacitors are connected in series. To prevent any cell from charging overvoltage, a balance resistor is required on a string of more than three cells. The AAT4712 also includes short-circuit protection circuitry for the discharge path from OUT to SYS to avoid large current discharging through the device over a long term and avoid damage to the device. Three parameters should be considered when selecting a supercapacitor. These parameters are capacitance, rated voltage, and ESR. Table 4 shows some recommended supercapacitors. Other parameters such as temperature range, RMS current, leakage current, etc. should also be considered during the system design. For proper thermal management and to take advantage of the low RDS(ON) of the AAT4712, certain circuit board layout rules should be followed: SYS Short Circuit Protection The series pass power MOSFET from VCC to SYS limits the current to a low level after the SYS output shorts to ground to protect the device and downstream components. During the fault condition, the power loop is still active to monitor the die temperature and reduce the current when the die temperature exceeds 130°C. Once the short-circuit fault is removed, the SYS voltage recovers to the normal value automatically. Manufacturer Cap-xx TDK PCB Layout Recommendations 1.VCC, VOUT, and VSYS should be routed using wide traces. 2. GND should be connected to a ground plane. The ground plane area connected to the ground pins should be made as large as possible. 3. For best performance, CIN and CSYS should be placed close to the VCC and SYS pins. 4. For maximum power dissipation of the AAT4712 TDFN package, the exposed pad should be soldered to the board ground plane to further increase local heat dissipation. A ground pad below the exposed pad is strongly recommended. Part Number Capacitance (mF) Rated Voltage (V) ESR (mΩ) Size LxWxH (mm) HS 203F HS 211F HS 206F HW 207F EDLC152344-551-2F-30 EDLC262020-501-2F-50 250 370 600 450 550 500 5.5 5.5 5.5 5.5 5.5 5.5 70 55 70 100 30 50 39x17x2.15 39x17x2.9 39x17x2.4 28.5x17x2.9 44x23x1.5 20x20x2.6 Table 4: Recommended Supercapacitors 12 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Evaluation Board Schematic POK U1 AAT4712 VCC RDY RADJ 18.2k 14 N/C 3 RSET 1.24M ADJ 2 ISET RDY 1 R1 1.74k D1 LED R2 1.74k D2 LED GND SYS 15 GND POK 16 4 SYS VCC 13 5 SYS VCC 12 6 SYS OUT 11 7 SYS OUT 10 8 SYS OUT 9 C2 10µF C1 10µF OUT C3 22µF Super Cap RB1 RB2 Figure 4: AAT4712 Evaluation Board Schematic. Evaluation Board Layout a: Top Side b: Bottom Side Figure 5: AAT4712 Evaluation Board Layout. Component Part Number Description Manufacturer U1 R1,R2 RSET RADJ C1, C2 C3 D1, D2 SUPERCAP, RB1, RB2 AAT4712 RC0603FR-071K74L RC0603FR-071M24L RC0603FR-0718K2L GRM21BR61C106K GRM21BR60J226M 0805KRCT Not populated Current Limited Switch with Capacitor Charger Res 1.74KΩ 1/10W 1% 0603 SMD Res 1.24MΩ 1/10W 1% 0603 SMD Res 18.2KΩ 1/10W 1% 0603 SMD Cap Ceramic 10μF 0805 X5R 16V 10% Cap Ceramic 22μF 0805 X5R 6.3V 20% Red LED 0805 Skyworks Yageo Murata HB Table 5: AAT4712 Evaluation Board Bill of Materials. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201912B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 30, 2012 13 DATA SHEET AAT4712 Power Path with Input Current Limit and Capacitor Charger Ordering Information Package Marking1 Part Number (Tape and Reel)2 TDFN34-16 G9XYY AAT4712IRN-T1 Skyworks Green™ products are compliant with all applicable legislation and are halogen-free. For additional information, refer to Skyworks Definition of Green™, document number SQ04-0074. Package Information3 TDFN34-16 3.000 ± 0.050 0.450 ± 0.050 1.600 ± 0.050 Detail "A" 0.230 ± 0.050 0.450 ± 0.050 3.300 ± 0.050 4.000 ± 0.050 Index Area Top View Bottom View 0.750 ± 0.050 Detail "A" 0.000 + 0.100 -0.000 0.203 REF Side View 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. Copyright © 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. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes. No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale. THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. 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