DATA SHEET AAT4672 Power Supply Selector Switch General Description Features The AAT4672 SmartSwitch™ is a member of Skyworks' Application Specific Power Management IC™ family. This device is a dual input, single output power supply selector switch, designed to operate from USB ports, AC adapter inputs, batteries, or any other power supply with an input voltage up to 6V. • Input Voltage Supply Range: 2.5V to 6V • High Level of Integration: ▪ Reverse Blocking Diode ▪ Current Sensing ▪ Programmable Current Limiting ▪ Automatic Power Supply Switching • Break-Before-Make Switch-Over ▪ Minimum Output Voltage Drop During Change-Over • Shutdown Current < 1μA • Thermal Protection • TSOPJW-12 Package The AAT4672 connects the supply on the MAIN pin to the OUT pin through a very low on-resistance power MOSFET when the device is enabled, the MAIN pin voltage is higher than the under voltage lockout (UVLO) threshold, and MAIN pin voltage is greater than the AUX pin voltage plus 200mV. The AUX pin connects to the OUT pin only when the MAIN pin voltage drops 0.2V below the AUX pin voltage and the AUX pin voltage is greater than the UVLO threshold. If both input supplies (MAIN/AUX) are below the UVLO threshold, then the OUT pin floats. The two internal power switches are current limited and the thresholds can be programmed through resistors on the IMAIN and IAUX pins respectively. A power level selection pin, PWRSEL, is provided to toggle the AUX current limit between 100% and 20% of the current limit setting programmed by the resistor on the IAUX pin. This is particularly useful for USB applications where the power supply can be powered by either a 500mA or a 100mA USB port. Applications • • • • • Bluetooth™ Headsets Cell Phones Digital Still Cameras MP3 Players Personal Data Assistants (PDAs) The AAT4672 is available in a thermally enhanced, space-saving, Pb-free 12-pin TSOPJW package and is specified for operation over the -40°C to +85°C temperature range. Typical Application AC Adapter MAIN OUT USB Port System Load AUX IMAIN USB H/L select PWRSEL IAUX RIAUX Enable RIMAIN EN GND Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 1 DATA SHEET AAT4672 Power Supply Selector Switch Pin Descriptions Pin Number Name Type 1, 2 3, 4 5 6, 7 MAIN AUX EN GND I I I I/O 8 PWRSEL I 9 10 11, 12 IAUX IMAIN OUT I I O Function Power supply 1 input. Power supply 2 input. Enable pin, active low. Ground. Power level select input for AUX-OUT switch. Logic “0”: 20% of the current limit programmed by RIAUX Logic “1”: 100% of the current limit programmed by RIAUX AUX-OUT switch current limit set input. MAIN-OUT switch current limit set input. Output pin. Pin Configuration TSOPJW-12 (Top View) MAIN MAIN AUX AUX EN GND 2 1 12 2 11 3 10 4 9 5 8 6 7 OUT OUT IMAIN IAUX PWRSEL GND Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 DATA SHEET AAT4672 Power Supply Selector Switch Absolute Maximum Ratings1 Symbol VN VX TLEAD IOUT Description [MAIN, AUX] to GND [OUT, EN, IMAIN, IAUX, PWRSEL] to GND Maximum Soldering Temperature (at Leads) Maximum Output Current Value Units -0.3 to 6.5 -0.3 to VN + 0.3 300 3 V V C A Value Units 160 625 -40 to 150 C/W mW C Thermal Information2 Symbol JA PD TJ Description Maximum Thermal Resistance Maximum Power Dissipation Operating Junction Temperature Range 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. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 3 DATA SHEET AAT4672 Power Supply Selector Switch Electrical Characteristics1 VMAIN/AUX = 5V, TA = -40 to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Symbol Operation VMAIN VAUX VMAIN-AUX Description MAIN Operating Voltage Range AUX Operating Voltage Range MAIN Switch-Over Threshold (Input Voltage Difference) VUVLO_MAIN MAIN Under-Voltage Lockout VUVLO_AUX AUX Under-Voltage Lockout IMAIN_OP MAIN Normal Operating Current IMAIN_SHDN MAIN Shutdown Mode Current IMAIN_SLP MAIN Sleep Current AUX Normal Operating Current IAUX_OP IAUX_SHDN AUX Shutdown Mode Current IAUX_SLP AUX Sleep Current Power Switches RDS(ON) MAIN MAIN-to-OUT FET On-Resistance RDS(ON) AUX AUX-to-OUT FET On-Resistance OUT Voltage Droop from the Lower Voltage of MAIN and AUX, When Switching Over Between MAIN and AUX Current Regulation tSOFT_START Soft-Start Delay ILIM_MAIN_range MAIN Current Limit Range VDROOP_OUT ILIM_AUX_range ILIM_MAIN ILIM_AUX AUX Current Limit Range MAIN Current Limit Accuracy AUX Current Limit Accuracy Conditions MAIN, AUX > 2.5V Chip Thermal Shutdown Temperature 2.5 2.5 VAUX + 0.15 Rising edge Hysteresis Rising edge Hysteresis VMAIN = 5V, VEN = 0V VMAIN = VEN = 5V, OUT open VMAIN = 2.5V, VAUX = 5V, VEN = 0V VAUX = 5V, VEN = 0V VAUX = VEN = 5V, OUT open VMAIN = 5V, VAUX = 2.5V, VEN = 0V Typ VAUX + 0.2 1 10 1 IO(OUT) = 0.5A, CO(OUT) = 10μF 150 Delay of start from EN , or UVLO RIMAIN = 100k PWRSEL = 5V PWRSEL = 0V Units 6 6 VAUX +0.25 2.3 V V 2.3 0.1 10 0.12 0.14 0.12 0.14 PWRSEL = 5V PWRSEL = 0V RIAUX = 100k Max 0.1 VMAIN = 5.0V VMAIN = 3.5V VAUX = 5.0V VAUX = 3.5V Logic Control / Protection VIH(EN) Logic High Threshold VIL(EN) Logic Low Threshold TSHDN Min 30 1 5 30 1 5 1 1 0.2 V μA μA μA μA μA μA mV 2.0 2.0 0.4 1.2 1.2 0.22 1.6 0.4 Threshold Hysteresis V 100 0.2 0.2 0.04 0.8 0.8 0.18 V 140 15 μs A A A A V V °C 1. The output charge voltage accuracy is specified over the 0° to 70°C ambient temperature range; operation over the -25°C to +85°C temperature range is guaranteed by design. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 DATA SHEET AAT4672 Power Supply Selector Switch Typical Characteristics IAUX Shutdown Current vs. Temperature 0.8 IAUX Shutdown Current (µA) IMAIN Shutdown Current (µA) IMAIN Shutdown Current vs. Temperature 0.6 0.4 VMAIN = 6.5V 0.2 VMAIN = 5V 0 VMAIN = 3.6V -0.2 -0.4 -40 VMAIN = 4.2V -15 10 35 60 85 0.8 0.6 VAUX = 6.5V 0.4 VAUX = 5V 0.2 0 VAUX = 3.6V -0.2 VAUX = 4.2V -0.4 -40 -15 10 IAUX Operation Current vs. Temperature (IOUT = 0A) (IOUT = 0A) 18 VMAIN = 6.5V 16 VMAIN = 5V 14 12 VMAIN = 4.2V 10 VMAIN = 3.6V 8 6 4 -40 -15 10 35 60 20 VAUX = 6.5V 18 VAUX = 5V 16 14 12 10 VAUX = 3.6V 8 4 -40 85 -15 10 35 60 85 Temperature (°C) RDS(ON) vs. Temperature Enable Threshold vs. Input Voltage 250 1.1 VMAIN/AUX = 3.5V Enable Threshold (V) RDS(ON) (mΩ) VAUX = 4.2V 6 Temperature (°C) VMAIN/AUX = 2.5V 150 100 VMAIN/AUX = 6.5V VMAIN/AUX = 5V 50 0 85 IMAIN Operation Current vs. Temperature 20 200 60 Temperature (°C) IAUX Operation Current (µA) IMAIN Operation Current (µA) Temperature (°C) 35 -40 -15 10 35 60 Temperature (°C) 85 110 1.05 1 VIH(EN) 0.95 0.9 0.85 VIL(EN) 0.8 0.75 0.7 0.65 0.6 2.5 3 3.5 4 4.5 5 5.5 6 6.5 Input Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 5 DATA SHEET AAT4672 Power Supply Selector Switch Typical Characteristics IMAIN Sleep Current vs. VMAIN Voltage IAUX Sleep Current vs. VAUX Voltage (VAUX = 6.5V) (VMAIN = 6.5V) 2.5 2 IAUX Sleep Current (µA) IMAIN Sleep Current (µA) 2.5 85°C 25°C 1.5 1 -40°C 0.5 0 2.5 3 3.5 4 4.5 5 6 5.5 85°C 2 25°C 1.5 1 -40°C 0.5 0 2.5 3 3.5 VMAIN Voltage (V) 4 4.5 5 5.5 6 VAUX Voltage (V) Current Limit vs. RIMAIN/IAUX Turn-On/Off Response (ROUT = 10Ω Ω; VMAIN = 5V) (VMAIN = 5V; VAUX = 3.3V; VOUT = VMAIN or VOUT = VAUX) 2.25 Current Limit (A) 2 VEN (2V/div) 1.75 2V 0V 1.5 1.25 1 0.75 VOUT (5V/div) 0V IOUT (500mA/div) 0A 0.5 0.25 0 50 100 150 200 250 300 350 400 450 500 Ω) RIMAIN/IAUX (kΩ Time (100µs/div) Short Circuit Through 0.3Ω Ω Response VIN (2V/div) 5V IOUT (5A/div) 0A VOUT (5V/div) 5V VIN (2V/div) 5V 2A IOUT (5A/div) 0A 0.6V VOUT (5V/div) Time (10µs/div) 6 Short Circuit Through 0.6Ω Ω Response 5V 2A 1.2V Time (10µs/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 DATA SHEET AAT4672 Power Supply Selector Switch Typical Characteristics Thermal Shutdown Response (VMAIN = 5V) VEN (2V/div) VOUT (2V/div) IOUT (2A/div) 2V 0V 0V 0A Time (40ms/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 7 DATA SHEET AAT4672 Power Supply Selector Switch Functional Block Diagram Switch 1 MAIN OUT IMAIN Thermal and Current Sense PWRSEL Logic Control EN IAUX GND AUX Switch 2 Truth Table Y = Yes, N = No, X = don’t care. Input Conditions VMAIN > UVLO VAUX > UVLO VMAIN > VAUX + 0.2V VOUT N Y N Y Y N N Y Y Y X X X Y N Floating VMAIN VAUX VMAIN VAUX Functional Description To power the OUT pin, at least one of the two input supplies (MAIN/AUX) must be greater than the UVLO threshold. If only one supply is greater than the UVLO threshold, the load will be connected to that particular supply when the device is enabled. If both supplies are above the UVLO threshold, the AAT4672 will connect the supply from the MAIN pin to the OUT pin when the device is enabled and the MAIN voltage is greater than the AUX voltage plus 0.2V (typical); otherwise, the AAT4672 will connect the supply from the AUX pin to the OUT pin. The two internal power switches are current limited; the current limits are programmed by the resistors on the IMAIN and IAUX pins respectively. 8 AAT4672 Applications Information Input Capacitors A 1μF or greater capacitor is generally recommended between MAIN and GND (CMAIN), and between AUX and GND (CAUX). An input capacitor is not required for basic operation; however, it is useful in preventing load transients from affecting up-stream circuits. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CMAIN/CAUX. There is no specific capacitor equivalent series resistance (ESR) requirement for CMAIN/CAUX. However, for higher current operation, ceramic capacitors are recommended for CMAIN/CAUX due to their inherent capability over tantalum capacitors to withstand Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 DATA SHEET AAT4672 Power Supply Selector Switch input current surges from low impedance sources such as batteries in portable devices. Output Capacitor A 1μF or greater capacitor is required between OUT and GND (COUT). As with the input capacitor, there is no specific capacitor ESR requirement. If desired, COUT may be increased to accommodate any load transient condition. For MAIN (power supply 1 input): ⎛ VIMAIN ⎞ RIMAIN = ⎝ I ⎠ · 200k CLMAIN ⎛0.5V⎞ = ⎝ 2A ⎠ · 200k = 50kΩ (49.9kΩ standard value) For AUX (power supply 2 input): EN Input The AAT4672 is enabled when VEN is ≤ 0.4V (logic ‘0’); conversely, the AAT4672 is disabled when VEN is ≥ 1.6V (logic ‘1’). PWRSEL Input When VPWRSEL is ≤ 0.4V (logic ‘0’) the AUX-OUT current limit is 20% of the current limit value programmed by RIAUX; when VPWRSEL is ≥ 1.6V (logic ‘1’), the AUX-OUT current limit is 100% of the current limit value programmed by RIAUX. Current Limit Resistor Selection The current limits for power supply 1 and power supply 2 inputs are set by resistors between IMAIN/IAUX and GND. The following equation can be used to select the appropriate resistor for a particular current limit: ⎛ VIMAIN/IAUX ⎞ ICLMAIN/AUX = ⎝ R · 200k IMAIN/IAUX ⎠ ICLIMAIN/AUX Current limit for MAIN and/or AUX pins respectively VIMAIN/IAUX Internally Regulated Voltage [0.5V ± 20%] on the IMAIN and IAUX pins respectively RIMAIN/IAUX IMAIN and/or IAUX Resistor 200k Internal Gain Factor Design Example A particular application requires that the current limit for MAIN be set to 2A and the current limit for AUX be set to 0.2A. What value of resistor is required for the IMAIN and IAUX pins respectively? ⎛ VIAUX ⎞ RIAUX = ⎝ I ⎠ · 200k CLAUX ⎛0.5V⎞ = ⎝0.2A⎠ · 200k = 500kΩ (499.9kΩ standard value) Thermal Considerations Since the AAT4672 has an internal current limit and overtemperature protection(thermal shutdown), junction temperature is rarely a concern. However, if the application requires large currents in a high temperature environment, it is possible that temperature rather than current limit will be the dominant regulating condition. In these applications, the maximum current available without risk of an over-temperature condition must be calculated. The maximum internal temperature while current limit is not active can be calculated using Equation 1 (Eq. 1). Eq. 1: TJ(MAX) = IMAX2 · RDS(ON)(MAX) · RθJA + TA(MAX) In Equation 1, IMAX is the maximum current required by the load. RDS(ON)(MAX) is the maximum rated RDS(ON) of the AAT4672 at high temperatures (consult the “RDSON vs. Temperature” performance graph in the “Typical Characteristics” section of this datasheet). For estimating the RDS(ON)(MAX) use the data on the “RDSON vs Temperature” performance graph and increase the value from the performance graph by 50%. RθJA is the thermal resistance between the AAT4672 die and the printed circuit board (PCB) onto which it is mounted; RJA is the thermal resistance of the TSOPJW-12 package. TA(MAX) is the maximum ambient temperature that the PCB under the AAT4672 would be if the AAT4672 were not dissipating power. Equation 1 can be rearranged to solve for IMAX, into Equation 2 (Eq. 2). Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 9 DATA SHEET AAT4672 Power Supply Selector Switch Eq. 2: IMAX = TSD(MIN) - TA(MAX) RDS(ON)(MAX) · RΘJA TSD(MIN) is the minimum temperature required to activate the AAT4672 over-temperature protection (thermal shutdown). With typical specification of 140°C, 125°C is a safe minimum value to use. For example, for a 2.5V input power supply application that is specified to operate in 50°C environments where the PCB operates at temperatures as high as 85°C. The application is sealed and its PCB is small, causing RθJA to be approximately 160°C/W. The RDS(ON)(MAX) is estimated to be 300mΩ (from the “RDS(ON) vs. Temperature” performance graph, where VIN = 2.5V at 85°C plus 50%). To find the maximum current (IMAX) for this application, use Equation 2: IMAX = 10 PCB Layout Recommendations For proper thermal management, to minimize PCB trace resistance, and to take advantage of the low RDS(ON) values of the two internal power switches in the AAT4672, certain circuit board layout rules should be followed: MAIN, AUX, and OUT should be routed using wider than normal traces. The two MAIN pins (1 and 2) and two AUX pins (3 and 4) should be connected to the same wide PCB trace; and GND should be connected to a ground plane. For best performance, input capacitors (CMAIN, CAUX) and output capacitor (COUT) should be placed as close to the package pins as possible. The AAT4672 evaluation board layout follows the printed circuit board layout recommendations and can be used as an example of an optimal board layout. 125°C - 85°C 300mΩ · 160°C/W = 0.913A Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 DATA SHEET AAT4672 Power Supply Selector Switch Evaluation Board Schematic C1 4.7μF MAIN AUX J1 C2 4.7μF 2 1 Header 2 C3 4.7μF U1 1 2 3 4 5 6 MAIN MAIN AUX AUX EN GND OUT OUT IMAIN IAUX SELECT GND 12 11 10 9 8 7 AAT4672 IMAIN IAUX R3 49.9K EN R1 100K OUT GND R2 49.9K PWRSEL Figure 1: AAT4672 Evaluation Board Schematic. Evaluation Board Layout Figure 2: AAT4672 Evaluation Board Top Side Layout. Figure 3: AAT4672 Evaluation Board Bottom Side Layout. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012 11 DATA SHEET AAT4672 Power Supply Selector Switch Ordering Information Package Marking1 Part Number (Tape and Reel)2 TSOPJW-12 ZWXYY AAT4672ITP-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 Information TSOPJW-12 2.85 ± 0.20 2.40 ± 0.10 0.20 + 0.10 - 0.05 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 7° NOM 0.04 REF 0.055 ± 0.045 0.15 ± 0.05 + 0.10 1.00 - 0.065 0.9625 ± 0.0375 3.00 ± 0.10 4° ± 4° 0.45 ± 0.15 0.010 2.75 ± 0.25 All dimensions in millimeters. 1. XYY = assembly and date code. 2. 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Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference. 12 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 201910A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 26, 2012