DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch General Description Features The AAT4285 SmartSwitch is a P-channel MOSFET power switch designed for high-side load switching applications. The MOSFET operates from a 3.0V to 13.2V input range making it ideal for applications in single or dual cell Lithium-Ion battery systems. The device has a typical RDS(ON) of 240mW at 12V, allowing a low forward voltage drop and high current handling capability. The device is a slew rate limited turn-on load switch and is functionally compatible with the AAT4250 and AAT4280 products, while offering a high operating voltage. The AAT4285 features fast load switch turn-on capability of 100µs and offers a shutdown load discharge circuit to rapidly turn off a load circuit when the switch is disabled. The quiescent supply current is very low, typically 25µA. •VIN Range: 3.0V to 13.2V • Low RDS(ON) ▪240mW Typical @ 12V ▪310mW Typical at 5V • 100µs Slew Rate Turn-on Time • Fast Shutdown Load Discharge • Low Quiescent Current ▪ Typically 25µA ▪ 1µA Maximum in Shutdown • TTL/CMOS Input Logic Level • Temperature Range: -40°C to +85°C • 8-pin SC70JW Package The AAT4285 is available in a Pb-free, 8-pin SC70JW package and is specified over the -40°C to +85°C temperature range. Applications • 2 Cell Lithium-Ion Batteries •Camcorders • Handheld Test Equipment • Load Switching Typical Application V IN IN IN C IN 1µF GND ON OUT V OUT AAT4285 ON/OFF GND × 4 C OUT 0.1µF GND Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 1 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Pin Descriptions Pin # Symbol 1,2 3 IN OUT 4 ON/OFF 5, 6, 7, 8 GND Function P-channel MOSFET source. Bypass to ground through a 1µF capacitor. P-channel MOSFET drain connection. Bypass to ground through a 0.1µF capacitor. Active high enable input. A logic low turns the switch off and the device consumes less than 1µA of current. Logic high resumes normal operation. Ground connection Pin Configuration SC70JW-8 (Top View) IN IN OUT ON/OFF 2 1 8 2 7 3 6 4 5 GND GND GND GND Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Absolute Maximum Ratings1 Symbol VIN VON VOUT IMAX IDM TJ Description IN to GND ON/OFF to GND OUT to GND Maximum Continuous Switch Current Maximum Pulsed Current Operating Junction Temperature Range Value Units -0.3 to 14 -0.3 to 14 -0.3 to VIN + 0.3 1.7 3.4 -40 to 150 V V V A A °C Value Units 140 714 °C/W mW Thermal Characteristics2 Symbol qJA PD Description Thermal Resistance Maximum Power Dissipation 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 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 3 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Electrical Characteristics1 VIN = 12V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C. Symbol VIN VUVLO VUVLO(hys) IQ IQ(OFF) ISHD Description Operation Voltage Under-Voltage Lockout Under-Voltage Lockout Hysteresis Quiescent Current Off Supply Current Off Switch Current RDS(ON) On Resistance TCRRDS TD(ON) TON TD(OFF) On Resistance Temperature Coefficient Output Turn-On Delay Time2 Turn-On Rise Time2 Output Turn-Off Delay Time2 Output Pull-Down Resistance During OFF ON/OFF Input Logic Low Voltage ON/OFF Input Logic High Voltage ON/OFF Leakage Current RPD VON(L) VON(H) ION Conditions Min Typ 3.0 2.7 250 25 ON/OFF = Active, IOUT = 0 ON/OFF = Inactive, OUT = Open ON/OFF = GND, VOUT = 0 VIN = 12V VIN = 5V VIN = 3.3V 0.1 240 310 380 2800 20 100 1 RLOAD = 20W, TA = 25°C RLOAD = 20W, TA = 25°C RLOAD = 20W, TA = 25°C ON/OFF Inactive, TA = 25°C VIN = 3V to 13V VIN = 3V to 13V VON/OFF = 13V 520 1.6 -1.0 Max Units 13.2 3.0 V V V µA µA µA 50 1.0 1.0 400 500 mW 40 250 10 ppm/°C µs µs µs 800 W 0.4 V V µA 1.0 1. The AAT4285 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. 2. Contact factory for other turn-on and delay options. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Typical Characteristics Quiescent Current vs. Temperature Quiescent Current vs. Input Voltage 35 Quiescent Current (µA) Quiescent Current (µA) 30 25 20 VIN = 12V VIN = 5V 15 VIN = 4.2V 10 5 VIN = 3.3V 0 30 25 20 15 10 5 0 -40 -15 10 35 60 85 0 2 4 Temperature (°C) 10 12 14 RDS(ON) vs. Input Voltage 420 500 450 VIN = 4.2V 380 RDS(ON) (mΩ) VIN = 3.3V 400 RDS(ON) (mΩ) 8 Input Voltage (V) RDS(ON) vs. Temperature 350 300 250 200 VIN = 12V VIN = 5V 150 0.1A 340 0.5A 300 2A 1A 260 220 100 -40 -15 10 35 60 85 3 4 5 Temperature (°C) 6 7 8 9 10 11 12 Input Voltage (V) ON/OFF Threshold Low vs. Input Voltage ON/OFF Threshold High vs. Input Voltage 1.05 ON/OFF Threshold (V) 0.95 ON/OFF Threshold (V) 6 -40°C 0.90 0.85 0.80 0.75 0.70 0.65 85°C 25°C 0.60 1.00 -40°C 0.95 0.90 0.85 0.80 0.75 25°C 0.70 85°C 0.65 0.55 3 5 7 9 Input Voltage (V) 11 13 3 5 7 9 11 13 Input Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 5 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Typical Characteristics Output Pull-Down Resistance vs. Temperature Turn-On (VIN = 12V; 600mA Load) 800 Resistance (Ω) 750 ON/OFF (5V/div) VIN = 4.2V 700 VIN = 3.3V 650 600 VOUT (5V/div) 550 500 IOUT (500mA/div) VIN = 12V VIN = 5V 450 400 -40 -15 10 35 Temperature (°C) 60 85 Time (25µs/div) Turn-Off (VIN = 12V; 600mA Load) ON/OFF (5V/div) VOUT (5V/div) IOUT (500mA/div) Time (10µs/div) 6 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Functional Block Diagram IN OUT UnderVoltage Lockout Level Shift Turn-On Slew Rate Control ON/OFF GND GND GND GND Functional Description The AAT4285 is a slew rate controlled P-channel MOSFET power switch designed for high-side load switching applications. The device operates with input voltages ranging from 3.0V to 13.2V, making it ideal for single- or multi-cell battery-powered applications. In cases where the input voltage drops below 3.0V, the AAT4285 MOSFET is protected from entering the saturated region of operation by automatically shutting down. In addition, the TTL compatible ON/OFF pin makes the AAT4285 an ideal level-shifted load switch. The slew rate controlling feature eliminates inrush current when the MOSFET is turned on, allowing the AAT4285 to operate with a small input capacitor, or no input capacitor at all. During slewing, the current ramps linearly until it reaches the level required for the output load condition. The proprietary control method works by careful control and monitoring of the MOSFET gate voltage. When the device is switched ON, the gate voltage is quickly increased to the threshold level of the MOSFET. Once at this level, the current begins to slew as the gate voltage is slowly increased until the MOSFET becomes fully enhanced. Once it has reached this point, the gate is quickly increased to the full input voltage and RDS(ON) is minimized. Applications Information Input Capacitor A 1µF or larger capacitor is typically recommended for CIN in most applications. A CIN capacitor is not required for basic operation. However, CIN is useful in preventing load transients from affecting upstream circuits. CIN should be located as close to the device VIN pin as practically possible. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor 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, such as batteries in portable devices. Output Capacitor For proper slew operation, a 0.1µF capacitor or greater between OUT and GND is recommended. The output capacitor has no specific capacitor type or ESR requirement. If desired, COUT may be increased without limit to accommodate any load transient condition without adversely affecting the device turn-on slew rate time. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 7 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Enable Function The AAT4285 features an enable / disable function. This pin (ON/OFF) is compatible with both TTL and CMOS logic. Reverse Output-to-Input Voltage Conditions and Protection Under normal operating conditions, a parasitic diode exists between the output and input of the load switch. The input voltage should always remain greater than the output load voltage, maintaining a reverse bias on the internal parasitic diode. Conditions where VOUT might exceed VIN should be avoided since this would forward bias the internal parasitic diode and allow excessive current flow into the OUT pin and possibly damage the load switch. In applications where there is a possibility of VOUT exceeding VIN for brief periods of time during normal operation, the use of a larger value CIN capacitor is highly recommended. A larger value of CIN with respect to COUT will affect a slower CIN decay rate during shutdown, thus preventing VOUT from exceeding VIN. In applications where there is a greater danger of VOUT exceeding VIN for extended periods of time, it is recommended to place a Schottky diode from IN to OUT (connecting the cathode to IN and anode to OUT). The Schottky diode forward voltage should be less than 0.45V. Thermal Considerations and High Output Current Applications The AAT4285 is designed to deliver a continuous output load current. The limiting characteristic for maximum safe operating output load current is package power dissipation. In order to obtain high operating currents, careful device layout and circuit operating conditions need to be taken into account. The following discussions will assume the load switch is mounted on a printed circuit board utilizing the minimum recommended footprint, as stated in the Layout Considerations section of this datasheet. At any given ambient temperature (TA), the maximum package power dissipation can be determined by the following equation: PD(MAX) = 8 TJ(MAX) - TA θJA Constants for the AAT4285 are maximum junction temperature, TJ(MAX) = 125°C, and package thermal resistance, θJA = 140°C/W. Worst case conditions are calculated at the maximum operating temperature where TA = 85°C. Typical conditions are calculated under normal ambient conditions where TA = 25°C. At TA = 85°C, PD(MAX) = 286mW. At TA = 25°C, PD(MAX) = 714mW. The maximum continuous output current for the AAT4285 is a function of the package power dissipation and the RDS of the MOSFET at TJ(MAX). The maximum RDS of the MOSFET at TJ(MAX) is calculated by increasing the maximum room temperature RDS by the RDS temperature coefficient. The temperature coefficient (TCRRDS) is 2800ppm/°C. Therefore, MAX RDS125°C = RDS25°C · (1 + TCRRDS · ΔT) MAX RDS125°C = 240mΩ · (1 + 0.0028 · (125°C - 25°C)) = 307mΩ For maximum current, refer to the following equation: IOUT(MAX) < PD(MAX) RDS For example, if VIN = 12V, RDS(MAX) = 307mΩ and TA = 25°C, IOUT(MAX) = 1.53A. If the output load current were to exceed 1.53A or if the ambient temperature were to increase, the internal die temperature would increase, and the device would be damaged. Higher peak currents can be obtained with the AAT4285. To accomplish this, the device thermal resistance must be reduced by increasing the heat sink area or by operating the load switch in a duty cycled manner. High Peak Output Current Applications Some applications require the load switch to operate at a continuous nominal current level with short duration, high-current peaks. The duty cycle for both output current levels must be taken into account. To do so, first calculate the power dissipation at the nominal continuous current level, and then add in the additional power dissipation due to the short duration, high-current peak scaled by the duty factor. For example, a 12V system using an AAT4285 operates at a continuous 100mA load current level and has short 2A current peaks. The current peak occurs for 500µs out of a 5ms period. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch First, the current duty cycle is calculated: % Peak Duty Cycle = x 500µs = 100 5.0ms % Peak Duty Cycle = 10% The load current is 100mA for 90% of the 5ms period and 2A for 10% of the period. De-rated for temperature: 240mΩ · (1 + 0.0028 · (125°C - 25°C)) = 307mΩ The power dissipation for a 100mA load is calculated as follows: PD(MAX) = IOUT2 · RDS PD(100mA) = (100mA)2 · 307mΩ PD(100mA) = 3.07mW PD(90%D/C) = %DC · PD(100mA) PD(90%D/C) = 0.90 · 3.07mW PD(90%D/C) = 2.76mW The power dissipation for 100mA load at 90% duty cycle is 2.76mW. Now the power dissipation for the remaining 10% of the duty cycle at 2A is calculated: PD(MAX) = IOUT2 · RDS PD(2A) = (2A)2 · 307mΩ PD(2A) = 1.23W PD(10%D/C) = %DC · PD(2A) PD(10%D/C) = 0.10 · 1.23mW PD(10%D/C) = 123mW The power dissipation for 2A load at 10% duty cycle is 123mW. Finally, the two power figures are summed to determine the total true power dissipation under the varied load. PD(TOTAL) = PD(100mA) + PD(2A) PD(TOTAL) = 2.76mW + 123mW PD(TOTAL) = 125.76mW The maximum power dissipation for the AAT4285 operating at an ambient temperature of 85°C is 286mW. The device in this example will have a total power dissipation of 123mW. This is well within the thermal limits for safe operation of the device; in fact, at 85°C, the AAT4285 will handle a 2A pulse for up to 23% duty cycle. At lower ambient temperatures, the duty cycle can be further increased. Printed Circuit Board Layout Recommendations For proper thermal management and to take advantage of the low RDS(ON) of the AAT4285, a few circuit board layout rules should be followed: VIN and VOUT should be routed using wider than normal traces, and GND should be connected to a ground plane. To maximize package thermal dissipation and power handling capacity of the AAT4285 SC70JW-8 package, the ground plane area connected to the ground pins should be made as large as possible. For best performance, CIN and COUT should be placed close to the package pins. Evaluation Board Layout The AAT4285 evaluation board layout follows the printed circuit board layout recommendations and can be used for good application guide. Refer to Figures 1 through 3. Note: Board layout shown is not to scale. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 9 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Figure 1: AAT4285 Evaluation Board Component Side Layout and Silk Screen. Figure 2: AAT4285 Evaluation Board Solder Side Layout. VOUT VIN 1 2 3 R1 100K 4 IN IN OUT EN GND GND GND GND 8 7 6 C2 0.1µF 5 AAT4285 C1 1µF JP1 ON/OFF C1 1µF X7R 16V 0805 GRM21BR71C105KA01 (C1 1µF X5R 16V 0603 GRM188R61C105KA93) C2 0.1µF X5R 16V 0805 GRM219R71C104KA01 (C2 0.1µF X7R 16V 0603 GRM188R71C104KA01) Figure 3: AAT4285 Evaluation Board Circuit Schematic Diagram. 10 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 DATA SHEET AAT4285 12V Slew Rate Controlled Load Switch Ordering Information Package Marking1 Part Number (Tape and Reel)2 SC70JW-8 UAXYY AAT4285IJS-3-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 SC70JW-8 2.20 ± 0.20 1.75 ± 0.10 0.50 BSC 0.50 BSC 0.50 BSC 0.225 ± 0.075 2.00 ± 0.20 0.100 7° ± 3° 0.45 ± 0.10 4° ± 4° 0.05 ± 0.05 0.15 ± 0.05 1.10 MAX 0.85 ± 0.15 0.048REF 2.10 ± 0.30 All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 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. 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Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202232A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • July 31, 2012 11