AAT4280A_0511

AAT4280A Slew Rate Controlled Load Switch General Description The AAT4280A SmartSwitch is a member of AnalogicTech's Application Specific Power MOSFET™ (ASPM™) product family. The AAT4280A is a P-channel MOSFET power switch designed for high-side load switching applications. The device has a typical RDS(ON) of 80mΩ, allowing increased load switch power handling capacity. The device is available in three different versions with flexible turn-on and turn-off characteristics — from very fast to slew rate limited. The standard AAT4280A (-1) version has a slew rate limited turn-on load switch and is functionally compatible with the AAT4250 device, while offering superior RDS(ON) characteristics. The AAT4280A (-2) version features fast load switch turn-on capabilities, typically less than 500ns turn-on and 3µs turn-off times. The AAT4280A (-3) variation offers a shutdown load discharge circuit to rapidly turn off a load circuit when the switch is disabled. All AAT4280A load switch versions operate with an input voltage ranging from 1.5V to 5.5V, making them ideal for both 3V and 5V systems. Input logic levels are TTL and 2.5V to 5V CMOS compatible. The quiescent supply current is very low, typically 25nA. The AAT4280A is available in a Pb-free, 8-pin SC70JW package and is specified over the -40°C to +85°C temperature range. Features • • • SmartSwitch™ • • • • • • 1.5V to 5.5V Input Voltage Range Very Low RDS(ON), Typically 80mΩ (5V) Slew Rate Limited Turn-On Time Options — 1ms — 0.5µs — 100µs Fast Shutdown Load Discharge Option Low Quiescent Current — 25nA (typ) TTL/CMOS Input Logic Level Temperature Range: -40ºC to +85°C 4kV ESD Rating 8-Pin SC70JW Package Applications • • • • • • Cellular Telephones Digital Still Cameras Hot Swap Supplies Notebook Computers Personal Communication Devices Personal Digital Assistants (PDAs) Typical Application V IN IN IN C IN 1µF ON OUT V OUT AAT4280A GND GND C OUT 0.1µF ON/OFF GND GND 4280A.2005.11.1.3 1 AAT4280A Slew Rate Controlled Load Switch Pin Descriptions Pin # 1, 5, 6, 7, 8 2 3 4 Symbol IN OUT ON/OFF GND Function This pin is the input to the P-channel MOSFET source. Bypass to ground through a 1.0µF capacitor. This pin is the P-channel MOSFET drain connection. Bypass to ground through a 0.1µF capacitor. Enable input. Ground connection. Pin Configuration SC70JW-8 (Top View) IN OUT ON/OFF GND 1 2 3 4 8 7 6 5 IN IN IN IN Selector Guide Slew Rate (typ) 1ms 0.5µs 100µs √ Part Number AAT4280A-1 AAT4280A-2 AAT4280A-3 Active Pull Down Enable Active High Active High Active High 2 4280A.2005.11.1.3 AAT4280A Slew Rate Controlled Load Switch Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol VIN VON VOUT IMAX IDM TJ TS TLEAD VESD Description IN to GND ON/OFF to GND OUT to GND Maximum Continuous Switch Current Maximum Pulsed Current Operating Junction Temperature Range Storage Temperature Range Maximum Soldering Temperature (at leads) ESD Rating2 - HBM IN ≥ 2.5V IN < 2.5V Value -0.3 to 6 -0.3 to 6 -0.3 to VIN + 0.3 2.3 6 3 -40 to 150 -65 to 150 300 4000 Units V V V A A A °C °C °C V Thermal Characteristics3 Symbol ΘJA PD Description Thermal Resistance Power Dissipation Value 140 714 Units °C/W mW 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. Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. 3. Mounted on an AAT4280A demo board in still 25ºC air. 4280A.2005.11.1.3 3 AAT4280A Slew Rate Controlled Load Switch Electrical Characteristics Unless otherwise noted, VIN = 5V, TA = -40°C to +85°C; typical values are TA = 25°C. Symbol Description AAT4280A All Versions VIN Operation Voltage IQ Quiescent Current IQ(off) Off Supply Current ISD(off) Off Switch Current Conditions Min 1.5 Typ Max 5.5 1 1 1 120 130 150 250 300 0.4 Units V µA µA µA RDS(on) On Resistance ON/OFF = Active ON/OFF = Inactive, OUT = Open ON/OFF = Inactive, VOUT = 0 VIN = 5V, TA = 25°C VIN = 4.2V, TA = 25°C VIN = 3V, TA = 25°C VIN = 1.8V, TA = 25°C VIN = 1.5V, TA = 25°C VIN = 1.8V to 5.5V1 VIN = 2.7V to 4.2V VIN = 4.2V to 5.5V VIN = 1.5V to 2.7V VON/OFF = 5.5V VIN = 5V, RLOAD = 10Ω, TA = 25°C VIN = 5V, RLOAD = 10Ω, TA = 25°C VIN = 5V, RLOAD = 10Ω, TA = 25°C VIN = 5V, RLOAD = 10Ω, TA = 25°C VIN = 5V, RLOAD = 10Ω, TA = 25°C VIN = 5V, RLOAD = 10Ω, TA = 25°C VIN = 5V, VIN = 5V, VIN = 5V, ON/OFF RLOAD = 10Ω, TA = 25°C RLOAD = 10Ω, TA = 25°C RLOAD = 10Ω, TA = 25°C = Inactive, TA = 25°C TCRDS VIL VIH On Resistance Temperature Coefficient ON/OFF Input Logic Low Voltage ON/OFF Input Logic High Voltage 80 85 100 160 200 2800 2 2.4 1.4 mΩ ppm/°C V V ISINK ON/OFF Input Leakage AAT4280A-1 TD(ON) Output Turn-On Delay TON Output Turn-On Rise Time TD(OFF) Output Turn-Off Delay Time AAT4280A-2 TD(ON) Output Turn-On Delay TON Output Turn-On Rise Time TD(OFF) Output Turn-Off Delay Time AAT4280A-3 TD(ON) Output Turn-On Delay TON Output Turn-On Rise Time TD(OFF) Output Turn-Off Delay Time RPD Output Pull-Down Resistance During OFF 1 20 1000 4 0.5 0.5 4 20 100 4 150 40 1500 10 2 1 10 40 150 10 250 µA µs µs µs µs µs µs µs µs µs Ω 1. For VIN outside this range, consult typical ON/OFF threshold curve. 4 4280A.2005.11.1.3 AAT4280A Slew Rate Controlled Load Switch Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Quiescent Current vs. Temperature 50 270 250 230 40 RDS(ON) vs. Input Voltage Quiescent Current (nA) 2A 1A 500mA RDS(ON) (mΩ) 210 190 170 150 130 110 90 70 30 20 10 0 -40 -20 0 20 40 60 80 100 100mA 1.5 1.8 2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 4.0 4.3 4.5 4.8 5.0 5.3 5.5 Temperature (°C) Input Voltage (V) RDS(ON) vs. Temperature ON/OFF Threshold (V) 120 110 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 1.4 -40 -20 0 20 40 60 80 100 ON/OFF Threshold vs. Input Voltage RDS(ON) (mΩ) 100 90 80 70 60 50 40 VIN = 3V VIH VIL 1.9 2.4 2.9 3.4 3.9 4.4 4 5.4 VIN = 5V Temperature (°C) Input Voltage (V) Off-Switch Current vs. Temperature Off-Switch Current (µA) 1.000 0.100 0.010 0.001 -40 -20 0 20 40 60 80 100 Temperature (°C) 4280A.2005.11.1.3 5 AAT4280A Slew Rate Controlled Load Switch Typical Characteristics—AAT4280A-1 Unless otherwise noted, VIN = 5V, TA = 25°C. AAT4280A-1 Turn-On (VIN = 3V; RL = 6Ω) AAT4280A-1 Turn-On (VIN = 5V; RL = 10Ω) ON/OFF (5V/div) VOUT (2V/div) ON/OFF (5V/div) VOUT (2V/div) IIN (200mA/div) Time (500µs/div) IIN (200mA/div) Time (500µs/div) AAT4280A-1 Turn-Off (VIN = 3V; RL = 6Ω) AAT4280A-1 Turn-Off (VIN = 5V; RL = 10Ω) ON/OFF (5V/div) ON/OFF (5V/div) VOUT (2V/div) VOUT (2V/div) IIN (200mA/div) Time (10µs/div) Time (10µs/div) IIN (200mA/div) 6 4280A.2005.11.1.3 AAT4280A Slew Rate Controlled Load Switch Typical Characteristics—AAT4280A-2 Unless otherwise noted, VIN = 5V, TA = 25°C. AAT4280A-2 Turn-On (VIN = 3V; RIN = 6Ω) AAT4280A-2 Turn-On (VIN = 5V; RL = 10Ω) ON/OFF (5V/div) VOUT (2V/div) ON/OFF (5V/div) VOUT (2V/div) IIN (200mA/div) Time (5µs/div) Time (5µs/div) IIN (200mA/div) AAT4280A-2 Turn-Off (VIN = 3V; RL = 6Ω) AAT4280A-2 Turn-Off (VIN = 5V; RL = 10Ω) ON/OFF (5V/div) ON/OFF (5V/div) VOUT (2V/div) VOUT (2V/div) IIN (200mA/div) IIN (200mA/div) Time (5µs/div) Time (5µs/div) 4280A.2005.11.1.3 7 AAT4280A Slew Rate Controlled Load Switch Typical Characteristics—AAT4280A-3 Unless otherwise noted, VIN = 5V, TA = 25°C. AAT4280A-3 Turn-On (VIN = 3V; RL = 6Ω) AAT4280A-3 Turn-On (VIN = 5V; RL = 10Ω) ON/OFF (5V/div) VOUT (2V/div) ON/OFF (5V/div) VOUT (2V/div) IIN (200mA/div) IIN (200mA/div) Time (50µs/div) Time (50µs/div) AAT4280A-3 Turn-Off (VIN = 3V; RL = 6Ω) AAT4280A-3 Turn-Off (VIN = 5V; RL = 10Ω) ON/OFF (5V/div) ON/OFF (5V/div) VOUT (2V/div) VOUT (2V/div) IIN (200mA/div) Time (5µs/div) Time (5µs/div) IIN (200mA/div) 8 4280A.2005.11.1.3 AAT4280A Slew Rate Controlled Load Switch Functional Block Diagram IN OUT Level Shift Turn-On Slew Rate Control * ON/OFF GND *AAT4280A-3 only Functional Description The AAT4280A is a family of flexible P-channel MOSFET power switches designed for high-side load switching applications. There are three versions of the AAT4280A with different turn-on and turn-off characteristics to choose from, depending upon the specific requirements of an application. The first version, the AAT4280A-1, has a moderate turn-on slew rate feature, which reduces inrush current when the MOSFET is turned on. This function allows the load switch to be implemented with either a small input capacitor or no input capacitor at all. During turn-on slewing, the current ramps linearly until it reaches the level required for the output load condition. The proprietary turn-on current 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. The second version, the AAT4280A-2, is a very fast switch intended for high-speed switching applications. This version has no turn-on slew rate control and no special output discharge features. The final switch version, the AAT4280A-3, has the addition of a minimized slew rate limited turn-on function and a shutdown output discharge circuit to rapidly turn off a load when the load switch is disabled through the ON/OFF pin. All versions of the AAT4280A operate with input voltages ranging from 1.5V to 5.5V. All versions of this device have extremely low operating current, making them ideal for battery-powered applications. The ON/OFF control pin is TTL compatible and will also function with 2.5V to 5V logic systems, making the AAT4280A an ideal level-shifting load switch. 4280A.2005.11.1.3 9 AAT4280A Slew Rate Controlled Load Switch 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. 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 effect 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 VIN to VOUT (connecting the cathode to VIN and anode to VOUT). The Schottky diode forward voltage should be less than 0.45V. Thermal Considerations and High Output Current Applications The AAT4280A 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: [TJ(MAX) - TA] θJA Output Capacitor For proper slew operation, a 0.1µF capacitor or greater between VOUT 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. Enable Function The AAT4280A features an enable / disable function. This pin (ON/OFF) is compatible with both TTL or CMOS logic. PD(MAX) = 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 VOUT pin and possibly damage the load switch. Constants for the AAT4280A are maximum junction temperature, TJ(MAX) = 125°C, and package thermal resistance, ΘJA = 120°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) = 333mW. At TA = 25°C, PD(MAX) = 833mW. The maximum continuous output current for the AAT4280A is a function of the package power dis- 10 4280A.2005.11.1.3 AAT4280A Slew Rate Controlled Load Switch sipation 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 (TC) is 2800ppm/°C. Therefore, MAX RDS125°C = RDS25°C × (1 + TC × ∆T) MAX RDS125°C = 120mΩ × (1 + 0.0028 × (125°C - 25°C)) = 154mΩ For maximum current, refer to the following equation: PD(MAX) RDS The load current is 100mA for 87.5% of the 4.61ms period and 2A for 12.5% of the period. Since the Electrical Characteristics do not report RDS(MAX) for 4V operation, it must be calculated approximately by consulting the chart of RDS(ON) vs. VIN. The RDS reported for 5V can be scaled by the ratio seen in the chart to derive the RDS for a 4V VIN: 120mΩ × 87mΩ /80mΩ = 130mΩ. De-rated for temperature: 130mΩ x (1 + 0.0028 × (125°C -25°C)) = 166mΩ. The power dissipation for a 100mA load is calculated as follows: PD(MAX) = IOUT2 × RDS PD(100mA) = (100mA)2 × 166mΩ PD(100mA) = 1.66mW PD(87.5%D/C) = %DC × PD(100mA) PD(87.5%D/C) = 0.875 × 1.66mW PD(87.5%D/C) = 1.45mW The power dissipation for 100mA load at 87.5% duty cycle is 1.45mW. Now the power dissipation for the remaining 12.5% of the duty cycle at 2A is calculated: PD(MAX) = IOUT2 × RDS PD(2A) = (2A)2 × 166mΩ PD(2A) = 664mW PD(12.5%D/C) = %DC × PD(2A) PD(12.5%D/C) = 0.125 × 664mW PD(12.5%D/C) = 83mW The power dissipation for 2A load at 12.5% duty cycle is 83mW. 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) = 1.45mW + 83mW PD(total) = 84.5mW The maximum power dissipation for the AAT4280A operating at an ambient temperature of 85°C is 333mW. The device in this example will have a total power dissipation of 84.5mW. This is well within the thermal limits for safe operation of the device; in fact, at 85°C, the AAT4280A will handle a 2A pulse for up to 50% duty cycle. At lower ambient temperatures, the duty cycle can be further increased. IOUT(MAX) < For example, if VIN = 5V, RDS(MAX) = 154mΩ and TA = 25°C, IOUT(MAX) = 2.3A. If the output load current were to exceed 2.3A 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 AAT4280A. To accomplish this, the device thermal resistance must be reduced by increasing the heat sink area or by operating the load switch in a dutycycle 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 4V system using an AAT4280A operates at a continuous 100mA load current level and has short 2A current peaks, as in a GSM application. The current peak occurs for 576µs out of a 4.61ms period. First, the current duty cycle is calculated: % Peak Duty Cycle: X/100 = 576µs/4.61ms % Peak Duty Cycle = 12.5% 4280A.2005.11.1.3 11 AAT4280A Slew Rate Controlled Load Switch Printed Circuit Board Layout Recommendations For proper thermal management and to take advantage of the low RDS(ON) of the AAT4280A, 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 dispation and power handling capacity of the AAT4280A 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 AAT4280A evaluation layout follows the printed circuit board layout recommendations and can be used for good applications layout. Refer to Figures 1 through 3. Note: Board layout shown is not to scale. Figure 1: Evaluation Board Top Side Silk Screen Layout / Assembly Drawing. Figure 2: Evaluation Board Component Side Layout. Figure 3: Evaluation Board Solder Side Layout. 12 4280A.2005.11.1.3 AAT4280A Slew Rate Controlled Load Switch Ordering Information Device Option AAT4280A-1 AAT4280A-2 AAT4280A-3 Package SC70JW-8 SC70JW-8 SC70JW-8 Marking1 NDXYY NEXYY NFXYY Part Number (Tape and Reel)2 AAT4280AIJS-1-T1 AAT4280AIJS-2-T1 AAT4280AIJS-3-T1 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Package Information SC70JW-8 0.50 BSC 0.50 BSC 0.50 BSC 1.75 ± 0.10 0.225 ± 0.075 2.00 ± 0.20 2.20 ± 0.20 0.048REF 0.15 ± 0.05 0.85 ± 0.15 1.10 MAX 0.100 7 ° ± 3° 0.45 ± 0.10 2.10 ± 0.30 4° ± 4° All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held for part numbers listed in BOLD. 4280A.2005.11.1.3 0.05 ± 0.05 13 AAT4280A Slew Rate Controlled Load Switch © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 14 4280A.2005.11.1.3