AAT4252A Dual Slew Rate Controlled Load Switch General Description Features The AAT4252A SmartSwitch™ is a dual P-channel MOSFET power switch designed for high-side loadswitching applications. Each MOSFET has a typical RDS(ON) of 105mΩ, allowing increased load switch current handling capacity with a low forward voltage drop. 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 4252A (-1) version has a slew-rate limited turn-on load switch. The AAT4252A (-2) version features a fast turn-on capabilities, typically less than 500ns turn-on and 3µs turn-off times. The AAT4252A (-3) variation offers a shutdown load discharge circuit to rapidly turn-off a load circuit when the switch is disabled. An additional feature is a slew-rate selector pin which can switch between fast and slow slew rate. • • All the AAT4252A load switch versions are designed to operate from 1.5V up to 6.5V, making then ideal for both 3V and 5V systems. Input logic levels are TTL and 2.5V to 5V CMOS compatible. The quiescent supply current is a very low 500nA. Applications • • • • • • • • • • • • • The AAT4252A is available in the Pb-free TSOPJW12 package and is specified over the -40°C to +85°C temperature range. SmartSwitch™ VIN Range: 1.5V to 6.5V Low RDS(ON) — 87mΩ Typical @ 5V — 196mΩ Typical @ 1.5V Slew Rate Turn-On Time Options — 1ms — 0.5µs — 100µs Fast Shutdown Load Discharge Option Low Quiescent Current — Typically 500nA TTL/CMOS Input Logic Level Temperature Range: -40ºC to +85°C Available in TSOPJW-12 package Cellular Telephones Digital Still Cameras Notebook Computers PDA Phones PDAs PMPs Smartphones Typical Application INA 2 INA OUTA 12 OUTA INB 5 INB OUTB 7 OUTB 3 ENA ON/OFF C1 1μF C2 1μF ON/OFF FAST/SLOW 4 1 AAT4252A C3 0.1μF C4 0.1μF ENB FAST GND N/C 6 8,9,10,11 4252A.2007.06.1.0 1 AAT4252A Dual Slew Rate Controlled Load Switch Pin Descriptions Pin # Symbol 1 2 FAST INA 3 ENA 4 ENB 5 INB 6 7 N/C OUTB 8, 9, 10, 11 12 GND OUTA Function Active-high input switches between FAST (Logic H) and SLOW (Logic L) slew rate. This is the pin to the P-channel MOSFET source for Switch A. Bypass to ground through a 1µF capacitor. INA is independent of INB. Active-High Enable Input A. A logic low turns the switch off and the device consumes less than 1µA of current. Logic high resumes normal operation. Active-High Enable Input B. A logic low turns the switch off and the device consumes less than 1µA of current. Logic high resumes normal operation. This is the pin to the P-channel MOSFET source for Switch B. Bypass to ground through a 1µF capacitor. INB is independent of INA. Not connected. This is the pin to the P-channel MOSFET drain connection. Bypass to ground through a 0.1µF capacitor. Ground connection. This is the pin to the P-channel MOSFET drain connection. Bypass to ground through a 0.1µF capacitor. Pin Configuration TSOPJW-12 (Top View) FAST INA ENA ENB INB N/C 2 1 12 2 11 3 10 4 9 5 8 6 7 OUTA GND GND GND GND OUTB 4252A.2007.06.1.0 AAT4252A Dual Slew Rate Controlled Load Switch Selector Guide Part Number Slew Rate (Typ) FAST (H) SLOW (L) Active Pull-Down Enable 1ms 0.5µs NO NO YES Active High Active High Active High 1 AAT4252A-1 AAT4252A-21 AAT4252A-3 100µs 1ms Absolute Maximum Ratings2 Symbol VIN VEN, FAST VOUT IMAX IDM TJ TLEAD VESD Description IN to GND EN, FAST to GND OUT to GND Maximum Continuous Switch Current IN ≥ 2.5V Maximum Pulsed Current IN ≤ 2.5V Operating Junction Temperature Range Maximum Soldering Temperature (at leads) ESD Rating3 - HBM Value Units -0.3 to 7 -0.3 to 7 -0.3 to VIN + 0.3 1.8 5.5 2.0 -40 to 150 300 4000 V V V A °C °C V Value Units 160 625 °C/W mW A Thermal Characteristics4 Symbol θJA PD Description Thermal Resistance Maximum Power Dissipation 1. Contact Sales for product availability 2. 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. 3. Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. 4. Mounted on an AAT4252A demo board in still 25°C air. 4252A.2007.06.1.0 3 AAT4252A Dual Slew Rate Controlled Load Switch Electrical Characteristics1 VIN = 5V, TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C. Per channel. Symbol Description Conditions Min AAT4252A All Versions VIN Operation Voltage IQ Quiescent Current IQ(OFF) ISD(OFF) Off Supply Current Off Switch Current2 RDS(ON) TCRRDS VIL VIH ISINK AAT4252A-12 TD(ON) TON TD(OFF) AAT4252A-22 TD(ON) TON TD(OFF) AAT4252A-3 TD(ON) On-Resistance 87 92 103 145 196 2800 Max Units 6.5 V 1.0 µA 1.0 1.0 155 µA µA mΩ 1.0 ppm/°C V V µA 0.4 1.4 Output Turn-On Delay Time Turn-On Rise Time Output Turn-OFF Delay Time VIN = 5V, RLOAD =10Ω, TA =25°C VIN = 5V, RLOAD =10Ω, TA =25°C VIN = 5V, RLOAD =10Ω, TA =25°C 10 600 2.0 40 1500 10 µs µs µs Output Turn-On Delay Time Turn-On Rise Time Output Turn-OFF Delay Time VIN = 5V, RLOAD =10Ω, TA =25°C VIN = 5V, RLOAD =10Ω, TA =25°C VIN = 5V, RLOAD =10Ω, TA =25°C 0.5 0.5 4.0 2 1.0 10 µs µs µs Output Turn-On Delay Time VIN = 5V, RLOAD VIN = 5V, RLOAD TA =25°C VIN = 5V, RLOAD TA =25°C VIN = 5V, RLOAD 10 40 µs 65 150 µs 600 1500 µs 2.0 10 µs 10 50 Ω Turn-On Rise Time TON Turn-On Rise Time RPD 1.5 ON/OFF = ACTIVE, FAST = VIN, IOUT = 0 ON/OFF = Inactive, OUT = Open ON/OFF = GND, VOUT = 0 VIN = 5V VIN = 4.2V VIN = 3.0V VIN = 1.8V VIN = 1.5V On Resistance Temp Co ON/OFF Input Logic Low Voltage VIN = 1.5V to 5.5V ON/OFF Input Logic High Voltage VIN = 1.5V to 5.5V ON/OFF Input Leakage VON/OFF = 5.5V TON TD(OFF) Typ Output Turn-OFF Delay Time Output Pull-Down Resistance During OFF =10Ω, TA =25°C =10Ω, FAST = 5V, =10Ω, FAST = 0V, =10 , TA =25°C ON/OFF = Inactive, TA =25°C 1. The AAT4252A 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 Sales for product availability. 4 4252A.2007.06.1.0 AAT4252A Dual Slew Rate Controlled Load Switch Typical Characteristics VIN = 5V, TA = 25°C unless otherwise noted. Quiescent Current vs. Temperature Quiescent Current vs. Input Voltage (No Load; Single Switch) (No Load; Single Switch) 0.7 Quiescent Current (µ µA) Quiescent Current (µ µA) 5 4.5 4 3.5 3 2.5 VIN = 5V 2 1.5 VIN = 3V 1 0.5 0 -40 -15 10 35 60 0.6 0.5 0.4 0.3 0.2 0.1 0 85 0 1 2 Temperature (°C) 3 4 5 6 Input Voltage (V) Typical ON/OFF Threshold vs. Input Voltage Off Supply Current vs. Temperature (No Load; EN = GND; VIN = 5V) 1.3 8 ON/OFF Threshold (V) Off Supply Current (µA) 9 7 6 5 4 3 2 1 0 -40 -15 10 35 60 1.2 VIL 1 0.9 0.8 0.7 0.6 1.5 85 VIH 1.1 2 2.5 On-Resistance vs. Temperature On-Resistance (mΩ Ω) On-Resistance (mΩ Ω) 4.5 5 5.5 250 120 VIN = 3V 100 80 VIN = 5V 60 40 20 -15 10 35 Temperature (°C) 4252A.2007.06.1.0 4 On-Resistance vs. Input Voltage 140 -40 3.5 Input Voltage (V) Temperature (°C) 0 3 60 85 230 210 190 170 ISW = 2A 150 130 110 90 70 50 1.5 ISW = 100mA 2 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) 5 AAT4252A Dual Slew Rate Controlled Load Switch Typical Characteristics VIN = 5V, TA = 25°C unless otherwise noted. Output Turn-On Output Turn-On 6 4 2 0 Switch A 4 2 0 (VINA/VINB/VEN = 5V; RL = 10Ω Ω) Enable Voltage (top) (V) Output Voltage (bottom) (V) Enable Voltage (top) (V) Output Voltage (bottom) (V) (VINA/VENA = 5V; VINB/VENB = 3V; RLA = 10Ω Ω; RLB = 20Ω) Switch B 6 4 2 Switch A 0 4 2 Switch B 0 Time (500µs/div) Time (500µs/div) Output Turn-On Output Turn-On 0.7 5 0.6 0.5 4 0.4 3 0.3 2 0.2 1 0.1 0 0 3.5 2 1 0 -1 Time (500µs/div) 6 0.1 1 0.5 0.05 0 0 Time (500µs/div) Output Turn-Off (VIN = 5V; RL = 10Ω Ω) Enable Voltage (top) (V) Output Voltage (middle) (V) Enable Voltage (top) (V) Output Voltage FAST (middle) (V) Output Voltage SLOW (bottom) (V) 3 0.15 6 0.7 5 0.6 0.5 4 0.4 3 0.3 2 0.2 1 0.1 0 0 Input Current (bottom) (A) 4 0.2 2 (RL = 10Ω Ω) 5 0.25 1.5 Output Turn-On 6 0.3 3 2.5 Time (500µs/div) 7 0.35 Input Current (bottom) (A) 6 Enable Voltage (top) (V) Output Voltage (middle) (V) (VIN = 3V; RL = 20Ω Ω) Input Current (bottom) (A) Enable Voltage (top) (V) Output Voltage (middle) (V) (VIN = 5V; RL = 10Ω Ω) Time (5µs/div) 4252A.2007.06.1.0 AAT4252A Dual Slew Rate Controlled Load Switch Typical Characteristics VIN = 5V, TA = 25°C unless otherwise noted. Output Turn-Off 3.5 0.35 3 0.3 2.5 0.25 2 0.2 0.15 1.5 1 0.1 0.5 0.05 0 0 Input Current (bottom) (A) Enable Voltage (top) (V) Output Voltage (middle) (V) (VIN = 3V; RL = 20Ω Ω) Time (5µs/div) 4252A.2007.06.1.0 7 AAT4252A Dual Slew Rate Controlled Load Switch Functional Block Diagram OUTA INA Turn-On Slew Rate Control Level Shift * ENA FAST OUTB INB Turn-On Slew Rate Control Level Shift * ENB GND *AAT4252A-3 version only 8 4252A.2007.06.1.0 AAT4252A Dual Slew Rate Controlled Load Switch Functional Description Applications Information The AAT4252A is a family of flexible dual P-channel MOSFET power switches designed for highside load switching applications. There are three versions of the AAT4252A with different turn-on and turn-off characteristics to choose from, depending upon the specific requirements of an application. Input Capacitor The first version, the AAT4252A-1, has a moderate turn-on slew rate feature, which reduces in-rush 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 the RDS(ON) is minimized. The second version, the AAT4252A-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 AAT4252A-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. Using the FAST input pin on the AAT4252A-3, the device can be manually switched to a slower slew rate. All versions of the AAT4252A operate with input voltages ranging from 1.5V to 6.5V. 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 AAT4252A an ideal level-shifting load switch. 4252A.2007.06.1.0 A 1μF or larger capacitor is typically recommended for CIN in most applications. A CIN capacitor is not required for basic operation; however, it 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 equivalent series resistance (ESR) requirement for CIN. However, for higher current CIN, 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 is required between VOUT and GND. Likewise, with the output capacitor, there is no specific capacitor ESR requirement. If desired, COUT may be increased without limit to accommodate any load transient condition without adversely affecting the slew rate. Enable Function The AAT4252A features an enable / disable function. This pin (ON) is active high and is compatible with TTL or CMOS logic. To assure the load switch will turn on, the ON control level must be greater than 2.0V. The load switch will go into shutdown mode when the voltage on the ON pin falls below 0.8V. When the load switch is in shutdown mode, the OUT pin is tri-stated, and quiescent current drops to leakage levels below 1μA. 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 9 AAT4252A Dual Slew Rate Controlled Load Switch the VOUT pin, possibly damaging 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 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. The maximum continuous output current for the AAT4252A 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 (TC) is 2800ppm/°C. Therefore, at 125°C: RDS(MAX) = RDS(25°C) · (1 + TC ⋅ ΔT) RDS(MAX) = 155mΩ · (1 + 0.002800 · (125°C - 25°C)) RDS(MAX) = 198mΩ For maximum current, refer to the following equation: Thermal Considerations and High Output Current Applications The AAT4252A 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 must 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 Printed Circuit Board Layout Recommendations section of this datasheet. At any given ambient temperature (TA), the maximum package power dissipation can be determined by the following equation: IOUT(MAX) < PD(MAX) RDS For example, if VIN = 5V, RDS(MAX) = 198mΩ, and TA = 25°C, IOUT(MAX) = 1.8A. If the output load current were to exceed 1.8A 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 AAT4252A. 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 cycle manner. Duty cycles with peaks less than 2ms in duration can be considered using the method below. High Peak Output Current Applications TJ(MAX) - TA PD(MAX) = θJA Constants for the AAT4252A are maximum junction temperature (TJ(MAX) = 125°C1) and package thermal resistance (θJA = 160°C/W). Worst case conditions are calculated at the maximum operating temperature, TA = 85°C. Typical conditions are calculated under normal ambient conditions where TA = 25°C. At TA = 85°C, PD(MAX) = 250mW. At TA = 25°C, PD(MAX) = 625mW. Some applications require the load switch to operate at a continuous nominal current level with short duration, high-current peaks. Refer to the IDM specification in the Absolute Maximum Ratings table to ensure the AAT4252A’s maximum pulsed current rating is not exceeded. 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 the additional power dissipation due to the short duration, high-current peak scaled by the duty factor. For example, a 4V system using an AAT4252A 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. 1. The actual maximum junction temperature of AAT4252A is 150°C. However,good design practice is to derate the maximum die temperature down to 125°C to prevent the possibility of over temperature damage. 10 4252A.2007.06.1.0 AAT4252A Dual Slew Rate Controlled Load Switch First, the current duty cycle is calculated: ⎛ x ⎞ ⎛ 576μs ⎞ % Peak Duty Cycle = ⎝ 100⎠ = ⎝ 4.61ms⎠ % Peak Duty Cycle = 12.5% 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 approximated by consulting the chart of RDS(ON) vs. VIN. The RDS reported for 5V at 100mA and 2A can be scaled by the ratio seen in the chart to derive the RDS for 4V VIN at 25°C : 155mΩ · 90mΩ/87mΩ = 160.3mΩ. De-rated for temperature: 160.3mΩ · (1 + 0.002800 x (125°C -25°C)) = 205mΩ. The power dissipation for a 100mA load is calculated as follows: PD(MAX) = IOUT2 · RDS PD(100mA) = (100mA)2 · 205mΩ PD(100mA) = 2.05mW PD(87.5%D/C) = %DC · PD(100mA) PD(87.5%D/C) = 0.875 · 2.05mW PD(87.5%D/C) = 1.8mW The power dissipation for 100mA load at 87.5% duty cycle is 1.97mW. Now the power dissipation for the remaining 12.5% of the duty cycle at 2A is calculated: The power dissipation for 2A load at 12.5% duty cycle is 102.6mW. 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) = 1.8mW + 102.6mW PD(total) = 104.4mW The maximum power dissipation for the AAT4252A operating at an ambient temperature of 85°C is 250mW. The device in this example will have a total power dissipation of 104.4mW. This is well within the thermal limits for safe operation of the device; in fact, at 85°C, the AAT4252A will handle a 2A pulse for up to 30% 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 AAT4252A, 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. For best performance, CIN and COUT should be placed close to the package pins. Evaluation Board Layout PD(2A) = (2A)2 · 205mΩ The AAT4252A evaluation layout follows the printed circuit board layout recommendations and can be used for good applications layout. Refer to Figures 1 and 2. PD(2A) = 820.97mW Note: Board layout shown is not to scale. PD(MAX) = IOUT2 · RDS PD(12.5%D/C) = %DC · PD(2A) PD(12.5%D/C) = 0.125 · 820.97mW PD(12.5%D/C) = 102.6mW 4252A.2007.06.1.0 11 AAT4252A Dual Slew Rate Controlled Load Switch Figure 1: Evaluation Board Top Side Layout. 12 Figure 2: Evaluation Board Bottom Side Layout. 4252A.2007.06.1.0 AAT4252A Dual Slew Rate Controlled Load Switch Ordering Information Device Option Package Marking1 Part Number (Tape and Reel)2 AAT4252A-3 TSOPJW-12 WSXYY AAT4252AITP-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 TSOPJW-12 2.85 ± 0.20 2.40 ± 0.10 0.10 0.20 +- 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. Sample stock is generally held on part numbers listed in BOLD. 4252A.2007.06.1.0 13 AAT4252A Dual 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. Except as provided in AnalogicTech’s terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. 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. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737- 4600 Fax (408) 737- 4611 14 4252A.2007.06.1.0