AAT4282A ANALOGICTECH | Alldatasheet
Document overview
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Technical content
Features
- V IN Range: 1.5V to 6.5V
- Low R DS(ON) — 60m Ω Typical @ 5V — 140m Ω Typical @ 1.5V
- Slew Rate Turn-On Time Options — 1ms — 0.5µs — 100µs
- Fast Shutdown Load Discharge Option
- Low Quiescent Current — Typically 1µA
- TTL/CMOS Input Logic Level
- Temperature Range -40ºC to 85°C
- FTDFN22-8 Package
Applications
- Cellular Telephones
- Digital Still Cameras
- Hotswap Supplies
- Notebook Computers
- PDA Phones
- PDAs
- PMPs
- Smartphones AAT4282A Dual Slew Rate Controlled Load Switch Typical Application INA INB OUTA OUTB INA INB ENA ENB FAST OUTA OUTB N/C ON/OFF FAST/SLOW 1μF 1μF C3 0.1μF 0.1μFGND ON/OFF AAT4282A 4282A.2007.09.1.1 1
Dual Slew Rate Controlled Load Switch 2 4282A.2007.09.1.1 Pin Descriptions Pin Configuration FTDFN22-8 (Top View) ENB INB INA ENA GND OUTB OUTA FAST Pin # Symbol Function 1 INA 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 2 ENA 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. 3 ENB 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. 4 INB 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. 5 OUTB This is the pin to the P-channel MOSFET drain connection. Bypass to ground through a 0.1µF capacitor.
6 GND Ground connection
7 FAST Active-high input Switches between FAST (Logic H) and SLOW (Logic L) Slew rate
8 OUTA This is the pin to the P-channel MOSFET drain connection. Bypass to ground through a 0.1µF capacitor.
Dual Slew Rate Controlled Load Switch 4282A.2007.09.1.1 3 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi- tions 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 1.5k Ω resistor into each pin. 3. Mounted on a AAT4282A demo board in still 25°C air. Selector Guide Absolute Maximum Ratings1 Thermal Characteristics3 Symbol Description Value Units θJA Thermal Resistance 70 °C/W PD Maximum Power Dissipation 1.78 W Symbol Description Value Units VIN IN to GND -0.3 to 7 V VEN, FAST EN, FAST to GND -0.3 to 7 V VOUT OUT to GND -0.3 to V IN + 0.3 V IMAX Maximum Continuous Switch Current 3 A IDM Maximum Pulsed Current Duty Cycle ≤ 10% 5.5 A TJ Operating Junction Temperature Range -40 to 150 °C TLEAD Maximum Soldering Temperature (at leads) 300 °C VESD ESD Rating2 – HBM 4000 V Slew Rate (Typ) Active Part Number FAST (H) SLOW (L) Pull-Down Enable AAT4282A-1* 1ms NO Active High AAT4282A-2* 0.5µs NO Active High AAT4282A-3 100µs 1ms YES Active High
Dual Slew Rate Controlled Load Switch 4 4282A.2007.09.1.1 1. The AAT4282A 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. Electrical Characteristics1 VIN = 5V, TA = -40 to 85°C unless otherwise noted. Typical values are at T A = 25°C. Per channel. Symbol Description Conditions Min Typ Max Units AAT4282A All Versions VIN Operation Voltage 1.5 6.5 V IQ Quiescent Current ON/OFF = ACTIVE, FAST = VIN, 1.0 µAIOUT = 0 IQ(OFF) Off Supply Current ON/OFF = Inactive, OUT = Open 1.0 µA ISD(OFF) Off Switch Current ON/OFF = GND, V OUT = 0 1.0 µA VIN = 6.5V 56 VIN = 5V 60 130 RDS(ON) On-Resistance A or B VIN = 4.2V 65 140 mΩVIN = 3.0V 76 160 VIN = 1.80V 110 230 VIN = 1.5V 140 280 TCRRDS On Resistance Temperature 2800 ppm/°CCoefficient VIL ON/OFF Input Logic Low Voltage V IN = 1.5V 0.4 V VIH ON/OFF Input Logic High Voltage V IN = 5V 1.4 V ISINK ON/OFF Input Leakage V ON/OFF = 5.5V 1.0 µA AAT4282A -12 TD(ON) Output Turn-On Delay Time V IN = 5V, RLOAD =10Ω, TA =25°C 20 40 µs TON Turn-On Rise Time V IN = 5V, RLOAD =10Ω, TA =25°C 1000 1500 µs TD(OFF) Output Turn-OFF Delay Time V IN = 5V, RLOAD =10Ω, TA =25°C 4.0 10 µs AAT4282A -22 TD(ON) Output Turn-On Delay Time V IN = 5V, RLOAD =10Ω, TA =25°C 0.5 2 µs TON Turn-On Rise Time V IN = 5V, RLOAD =10Ω, TA =25°C 0.5 1.0 µs TD(OFF) Output Turn-OFF Delay Time V IN = 5V, RLOAD =10Ω, TA =25°C 4.0 10 µs AAT4282A -3 TD(ON) Output Turn-On Delay Time V IN = 5V, RLOAD =10Ω, TA =25°C 20 40 µs TON Turn-On Rise Time VIN = 5V, RLOAD =10Ω, FAST = 5V, 100 150 µsTA =25°C TON Turn-On Rise Time VIN = 5V, RLOAD =10Ω, FAST = 0V, 1000 1500 µsTA =25°C TD(OFF) Output Turn-OFF Delay Time V IN = 5V, RLOAD =10Ω, TA =25°C 4.0 10 µs RPD Output Pull-Down Resistance ON/OFF = Inactive, TA =25°C 150 250 ΩDuring OFF
VIN = 5V, TA = 25ºC unless otherwise noted. On-Resistance vs. Temperature Temperature (°C) On-Resistance (mΩΩ) 100 -40 -15 10 35 60 85 VIN = 3V VIN = 5V On-Resistance vs. Input Voltage Input Voltage (V) On-Resistance (mΩΩ) 100 120 140 160 180 200 220 ISW = 2A ISW = 100mA Typical ON/OFF Threshold vs. Input Voltage Input Voltage (V) ON/OFF Threshold (V) 0.6 0.7 0.8 0.9 1.1 1.2 1.3 VIH VIL Off Supply Current vs. Temperature (No Load; EN = GND; VIN = 5V) Temperature (°C) Off Supply Current (µA) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 -40 -15 10 35 60 85 Quiescent Current vs. Input Voltage (No Load; Single Switch) Input Voltage (V) Quiescent Current (µA) 0123456 Quiescent Current vs. Temperature (No Load; Single Switch) Temperature (°C) Quiescent Current (µA) -40 -15 10 35 60 85 VIN = 5V VIN = 3V AAT4282A Dual Slew Rate Controlled Load Switch 4282A.2007.09.1.1 5
VIN = 5V, TA = 25ºC unless otherwise noted. Output Turn-On (RL = 10ΩΩ) Time (500µs/div) Voltage (V) EN VOUT (FAST = VIN) VOUT (FAST = GND) Output Turn-On (VIN = 1.8V; RL = 10ΩΩ) Time (200µs/div) Voltage (V) -0.5 0.5 1.5 2.5 3.5 VEN VOUT (FAST = VIN) VOUT (FAST = GND) Output Turn-On Delay Time (VIN = 3V; RL = 20ΩΩ) Time (50µs/div) Voltage (top) (V) Current (bottom) (A) 0.2 0.4 EN VOUT IIN Output Turn-On Delay Time (VIN = 5V; RL = 10ΩΩ) Time (50µs/div) Voltage (top) (V) Current (bottom) (A) 0.5 EN VOUT IIN Output Turn-On Delay Time (VINA/VINB/VEN = 5V; RL = 10ΩΩ) Time (50µs/div) Output Voltage Channel A (top) (V) Output Voltage Channel B (bottom) (V) ENA ENB VOUT VOUT Output Turn-On Delay Time (VINA/VENA = 5V; VINB/VENB = 3V; RLA = 10ΩΩ; RLB = 20Ω) Time (50µs/div) Output Voltage Channel A (top) (V) Output Voltage Channel B (bottom) (V) ENA ENB VOUT VOUT AAT4282A Dual Slew Rate Controlled Load Switch 6 4282A.2007.09.1.1
Dual Slew Rate Controlled Load Switch 4282A.2007.09.1.1 7 Typical Characteristics VIN = 5V, TA = 25ºC unless otherwise noted. Output Turn-Off Delay Time (VIN = 1.8V; RL = 10ΩΩ) Time (5µs/div) Enable Voltage (top) (V) Output Voltage (bottom) (V) VEN -0.5 0.5 1.5 2.5 3.5 VOUT Output Turn-Off Delay Time (VIN = 5V; RL = 10ΩΩ) Time (5µs/div) Voltage (top) (V) Current (bottom) (A) 0.2 0.4 0.6 0.8 1.2 EN IIN VOUT Output Turn-Off Delay Time (VIN = 3V; RL = 20ΩΩ) Time (5µs/div) Voltage (top) (V) Current (bottom) (A) 0.2 0.4 EN IIN VOUT
Dual Slew Rate Controlled Load Switch 8 4282A.2007.09.1.1 Functional Description The AAT4282A is a family of flexible dual P-chan- nel MOSFET power switches designed for high- side load switching applications. There are three versions of the AAT4282A with different turn-on and turn-off characteristics to choose from, depending upon the specific requirements of an application. The first version, the AAT4282A-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 slew- ing, the current ramps linearly until it reaches the level required for the output load condition. The Functional Block Diagram * AAT4282A-3 version only OUTA ON/OFF A INA GND Level Shift Turn-On Slew Rate Control OUTB ON/OFF B INB Level Shift Turn-On Slew Rate Control FAST/ SLOW
Dual Slew Rate Controlled Load Switch 4282A.2007.09.1.1 9 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 thresh- old level of the MOSFET. Once at this level, the current begins to slew as the gate voltage is slow- ly 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 R DS(ON) is minimized. The second version, the AAT4282A-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 AAT4282A-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 AAT4282A-3, the device can be manually switched to a slower slew rate. All versions of the AAT4282A 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 AAT4282A an ideal level-shifting load switch. Applications Information Input Capacitor A 1μF or larger capacitor is typically recommended for C IN in most applications. A C IN capacitor is not required for basic operation; however, it is useful in preventing load transients from affecting upstream circuits. C IN should be located as close to the device VIN pin as practically possible. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for C IN. There is no specific capacitor equivalent series resistance (ESR) requirement for C IN. However, for higher current operation, ceram- ic capacitors are recommended for CIN due to their inherent capability over tantalum capacitors to with- stand 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 spe- cific capacitor ESR requirement. If desired, C OUT may be increased without limit to accommodate any load transient condition without adversely affecting the slew rate. Enable Function The AAT4282A features an enable / disable func- tion. 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 1.4V. The load switch will go into shutdown mode when the voltage on the ON pin falls below 0.4V. 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, main- taining a reverse bias on the internal parasitic diode. Conditions where V OUT might exceed V IN should be avoided since this would forward bias
Dual Slew Rate Controlled Load Switch 10 4282A.2007.09.1.1 the internal parasitic diode and allow excessive current flow into the VOUT pin, possibly damaging the load switch. In applications where there is a possibility of V OUT exceeding VIN for brief periods of time during normal operation, the use of a larger value C IN capacitor is highly recommended. A larg- er value of C IN with respect to C OUT will effect a slower CIN decay rate during shutdown, thus pre- venting V OUT from exceeding V IN. In applications where there is a greater danger of VOUT exceeding VIN for extended periods of time, it is recommend- ed to place a Schottky diode from VIN to VOUT (con- necting 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 AAT4282A 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 (T A), the maxi- mum package power dissipation can be deter- mined by the following equation: Constants for the AAT4282A are maximum junction temperature (T J(MAX) = 125°C) and package ther- mal resistance ( θJA = 70°C/W). Worst case condi- tions are calculated at the maximum operating tem- perature, T A = 85°C. Typical conditions are calcu- lated under normal ambient conditions where T A = 25°C. At T A = 85°C, P D(MAX) = 571mW. At T A = 25°C, PD(MAX) = 1429mW. The maximum continuous output current for the AAT4282A is a function of the package power dis- sipation and the R DS of the MOSFET at TJ(MAX). The maximum RDS of the MOSFET at T J(MAX) is calcu- lated by increasing the maximum room tempera- ture R DS by the R DS temperature coefficient. The temperature coefficient (TC) is 2800ppm/°C. Therefore, at 125°C: R DS(MAX) = RDS(25°C) · (1 + TC · ΔT)Ω RDS(MAX) = 166.4mΩ For maximum current, refer to the following equation: For example, if VIN = 5V, RDS(MAX) = 166.4mΩ, and TA = 25°C, IOUT(MAX) = 2.93A. If the output load cur- rent were to exceed 2.93A or if the ambient tem- perature were to increase, the internal die temper- ature would increase and the device would be damaged. Higher peak currents can be obtained with the AAT4282A. 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 described in the High Peak Current Applications section of this datasheet. IOUT(MAX) PD(MAX) RDS PD(MAX) TJ(MAX) - TA θJA 1 The actual maximum junction temperature of AAT4282A is 150°C. However, good designed practice is to derate the maximum die tem- perature down to 125 °C to prevent the possibility of over-temperature damage.
Dual Slew Rate Controlled Load Switch 4282A.2007.09.1.1 11 High Peak Output Current Applications Some applications require the load switch to oper- ate at a continuous nominal current level with short duration, high-current peaks. Refer to the I DM spec- ification in the Absolute Maximum Ratings table to ensure the AAT4282A’s maximum pulsed current rating is not exceeded. The duty cycle for both out- put current levels must be taken into account. To do so, first calculate the power dissipation at the nom- inal continuous current level, and then add the additional power dissipation due to the short dura- tion, high-current peak scaled by the duty factor. For example, a 4V system using an AAT4282A which has channel A operates at a continuous 1A load current level, and channel B operates at a continuous 100mA load current level and has short 3A current peaks, as in a GSM application. The current peak occurs for 576μs out of a 4.61ms peri- od. First, the current duty cycle is calculated: The load current is 100mA for 87.5% of the 4.61ms period and 3A for 12.5% of the period. Since the Electrical Characteristics do not report R DS(MAX) for 4V operation, it must be approximated by consult- ing the chart of R DS(ON) vs. VIN. The R DS reported for 5V at 100mA and 3A can be scaled by the ratio seen in the chart to derive the R DS for 4V V IN at 25°C: 130m Ω · 63m Ω /60mΩ = 136.5m Ω . De- rated for temperature: 136.5m Ω · (1 + 0.002800 · For channel A, the power dissipation for a continu- ous 1A load is calculated as follows: PD(CHA) = IOUT 2 · RDS = (1A)2 · 174.7mΩ = 174.7mW For channel B, the power dissipation for 100mA load is calculated as follows: PD(MAX) = IOUT 2 · RDS PD(100mA) = (100mA)2 · 174.7mΩ PD(100mA) = 1.75mW PD(87.5%D/C) = %DC · PD(100mA) PD(87.5%D/C) = 1.53mW The power dissipation for 100mA load at 87.5% duty cycle is 1.53mW. Now the power dissipation for the remaining 12.5% of the duty cycle at 3A is calculated: P D(MAX) = IOUT 2 · RDS PD(3A) = (3A)2 · 174.7mΩ PD(3A) = 1572mW PD(12.5%D/C) = %DC · PD(3A) PD(12.5%D/C) = 196.7mW Finally, the total power dissipation for channels A and B is determined as follows: PD(total) = PD(CHA) + PD(100mA) + PD(3A) PD(total) = 174.7mW + 1.53mW + 196.7mW PD(total) = 373mW The maximum power dissipation for the AAT4282A operating at an ambient temperature of 85°C is 373mW. The device in this example will have a total power dissipation of 571mW. This is well with- in the thermal limits for safe operation of the device; in fact, at 85°C, the AAT4282A will handle a 3A pulse for up to 25% duty cycle. At lower ambi- ent temperatures, the duty cycle can be further increased. Printed Circuit Board Layout Recommendations For proper thermal management, and to take advantage of the low R DS(ON) of the AAT4282A, a few circuit board layout rules should be followed: V IN and V OUT should be routed using wider than normal traces, and GND should be connected to a ground plane. For best performance, C IN and COUT should be placed close to the package pins. % Peak Duty Cycle = % Peak Duty Cycle = x 100 ⎝⎠ = 12.5% 576μs 4.61ms
Dual Slew Rate Controlled Load Switch 4282A.2007.09.1.1 13
Ordering Information
All dimensions in millimeters. 2.000 ± 0.050 Index Area 2.000 ± 0.050 Top View 0.500 ± 0.050 Detail "A" 0.400 ± 0.050 Pin 1 Identification 0.000 + 0.100 - 0.000 Side View 0.230 ± 0.050 0.750 ± 0.050 Bottom View 0.450 ± 0.0500.250 ± 0.050 Detail "A" 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. Device Option Package Marking 1 Part Number (Tape and Reel)2 AAT4282A-3 FTDFN22-8 WKXYY AAT4282AIPS-3-T1 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, FTDFN, 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.
Dual Slew Rate Controlled Load Switch 14 4282A.2007.09.1.1 Advanced Analogic Technologies, Inc.
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