AAT4601A ANALOGICTECH | Alldatasheet

Document overview

  • Manufacturer or author: janekim
  • PDF pages: 16

Technical content

Features

  • Input Voltage: 2.7V to 5.5V
  • Programmable Over-Current Threshold
  • Low Quiescent Current — 12µA Typical — Less Than 1µA with Switch Off
  • Only 2.5V Needed for ON Control
  • Thermal Shutdown
  • Fault Flag
  • 2ms Fault Blanking
  • Under-Voltage Lockout
  • Temperature Range: -40°C to +85°C
  • 4kV ESD rating
  • UL Approved—File No. E217765
  • 8-Pin SOP, TSSOP, or MSOP Package

Applications

  • Hot Swap Supplies
  • Notebook Computers
  • Peripheral Ports
  • USB Ports UL Recognized Component Typical Application AAT4601A ON IN OUT SET GND ON 1µF 100kΩ R SET 1µF INPUT OUTPUT IN OUT FAULT

(Top View) (Top View) TSSOP-8 (Top View) IN IN ON GND FAULT OUT OUT SET4 1 2 OUT FAULT OUT SET IN IN ON GND 1 2 OUT FAULT OUT SET IN IN ON GND Pin # Symbol Function 1, 2 IN These pins are the input to the P-channel MOSFET source. Connect a 1µF capacitor from IN to GND. 3 ON Active low enable input. A logic low turns the switch on. 4 GND Ground. 5 SET Current limit set input. A resistor from SET to ground sets the current limit for the switch. 6, 7 OUT These pins are the P-channel MOSFET drain connection. Connect a 1µF capacitor from OUT to GND. 8 FAULT Fault indication output. This open-drain output goes low when in current limit or when the die temperature exceeds +135ºC, with a 2ms delay after the fault event occurs. AAT4601A 1.8A Current Limited P-Channel Switch 2 4601A.2006.05.1.5

1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 3 Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Thermal Characteristics3 Symbol Description Value Units SOP-8 100 ΘJA Maximum Thermal Resistance TSSOP-8 150 °C/W MSOP-8 150 SOP-8 1.25 W PD Maximum Power Dissipation TSSOP-8 833 mWMSOP-8 833 Symbol Description Value Units VIN IN to GND -0.3 to 6 V VON, VFAULT ON, FAULT to GND -0.3 to V IN + 0.3 V VSET ,VOUT SET, OUT to GND -0.3 to V IN + 0.3 V IMAX Maximum Continuous Switch Current 3 A TJ Operating Junction Temperature Range -40 to 150 °C TLEAD Maximum Soldering Temperature (at Leads) 300 °C VESD ESD Rating—HBM 2 4000 V 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 an FR4 printed circuit board.

1.8A Current Limited P-Channel Switch 4 4601A.2006.05.1.5

Electrical Characteristics

VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are T A = 25°C. Symbol Description Conditions Min Typ Max Units VIN Operation Voltage 2.7 5.5 V IQ Quiescent Current V IN = 5V, ON = GND, IOUT = 0 12 30 µA IQ(OFF) Off-Supply Current ON = IN, V IN = 5.5V 0.004 1 µA ISD(OFF) Off-Switch Current ON = IN, V IN = 5.5V, VOUT = 0 0.07 15 µA VUVLO Under-Voltage Lockout Rising Edge, 1% Hysteresis 2.0 2.3 2.7 V VIN = 5.0V 70 120 RDS(ON) On Resistance VIN = 4.5V 75 130 VIN = 3.0V 80 150 mΩ VIN = 3.0V, TA = 25°C 80 110 ILIM Current Limit R SET = 20.5kΩ 750 1000 1250 mA ILIM(MIN) Minimum Current Limit 260 mA OTMP Shutdown Temperature V IN = 5V 125 ºC VONL ON Input Low Voltage 0.8 V VONH ON Input High Voltage VIN = 2.7V to 3.6V 2.0 VIN = 4.5V to 5.5V 2.4 V IONSINK ON Input leakage V ON = 5.5V 0.01 1 µA VFAULTL FAULT Logic Output Low Voltage I SINK = 1mA 0.08 0.4 V IFSINK FAULT Logic Output High Leakage V FAULT = 5.5V 0.05 1 µA TRESP Current Limit Response Time V IN = 5V 2 µs TBLANK Fault Blanking Time After Turn-On 2 ms TOFF Turn-Off Time1 VIN = 5V 20 µs TON Turn-On Time1 VIN = 5V 200 µs 1. Guaranteed by design.

Unless otherwise noted, VIN = 5V, TA = 25°C. Off-Switch Current vs. Temperature 0.1 0.01 0.001 0.0001 -40 -20 0 20 40 60 80 100 120 140 Temperature (°C) Off-Switch Current (μA) Off-Supply Current vs. Temperature 0.0001 0.001 0.01 0.1 -40 -20 0 20 40 60 80 100 120 140 Temperature Off-Supply Current (μA) (°C) RSET * ILIM Product vs. ILIM Typical ILIM (A) Product (V) 18000 19000 20000 21000 22000 23000 24000 25000 Current Limit (RSET = 20.5kΩ; VIN = 5.0V) Output Voltage (V) Output Current (A) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 012345 0123456 10152025 Quiescent Current Input Voltage (V) Input Curent (μA) Quiescent Current vs. Temperature -40 -20 0 20 40 60 80 100 120 Temperature (°C) Quiescent Current (μA) AAT4601A 1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 5

1.8A Current Limited P-Channel Switch 6 4601A.2006.05.1.5 Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Short-Circuit Through 0.6Ω -20 0 20 40 60 80 100 120 140 Time (μs) Input and Output Voltage (V) Output Current (A) Output Current Input Voltage Output Voltage Short-Circuit Through 0.3Ω 02468 Time (μs) Input and Output Voltage (V) Output Current (A) Output Current Input Current Output Current Switch Turn-Off Time (IOUT = ILIMIT) - 4 - 20246 Time (μs) Voltage (V) Output ON Switch Turn-On Time (IOUT = ILIMIT) -20 -10 0 40 60 80 Time (μs) Voltage (V) Output ON Turn-Off Time vs. Temperature 0.2 0.4 0.6 0.8 1.0 1.8 1.6 1.4 1.2 2.0 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Turn-Off Time (μs) VIN = 5V VIN = 3V Turn-On Time vs. Temperature 203040 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Turn-On Time (μs) VIN =3 V VIN =5 V

Unless otherwise noted, VIN = 5V, TA = 25°C. RDS(ON) vs. Temperature 100 -40 -20 0 20 40 60 80 Temperature (°C) RDS(ON) (mΩ) VIN = 4.5V VIN = 3V Fault Delay vs. Temperature 0.5 1.0 1.52.0 2.5 -40 -20 0 20 40 60 80 100Temperature (°C) Fault Delay (ms) AAT4601A 1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 7

1.8A Current Limited P-Channel Switch 8 4601A.2006.05.1.5 Functional Block Diagram IN ON SET FAULT OUT Under- Voltage Lockout Over-Temperature Protection 1.2V Reference Current Limit Functional Description The AAT4601A is an integrated MOSFET load switch with an adjustable current limit, over-tem- perature protection, level-shifted input, and a fault flag. The current limit control is combined with an over-temperature thermal limit circuit to provide a comprehensive system to protect the load switch under short-circuit or other adverse operating con- ditions. The AAT4601A is ideally suited for control and protection of peripheral ports such as USB, RS232, and parallel ports. The current limit and over-temperature circuits will act independently. The device current limit is acti- vated when the output load current exceeds an internal threshold level. The internal current limit threshold is determined by an external resistor connected between the SET pin and ground. The minimum current limit threshold is specified by I LIM(MIN). If the load switch ambient temperature becomes excessive or if a short-circuit condition persists, the die temperature will rise causing the over-temperature protection circuit to activate. If a current limit level less than I LIM(MIN) is required, the AAT4601A can be used to operate in foldback current limit mode. To achieve this, an R SET value can be chosen to program a current limit lower than I LIM(MIN); in this case, when the load current reaches ILIM(MIN), the current will immediately drop, limiting at the programmed value. If the current limit or over-temperature protection circuits are active for more than 2ms, the system will be informed via the FAULT flag. The 2ms delay allows the AAT4601A to be turned on into capaci- tive loads without activating the FAULT flag. The open drain FAULT output can be connected direct- ly to system controllers driven by voltage levels less than the IN pin voltage without additional level shifting circuitry. The load switch is turned off by applying a logic high level to the ON pin. The AAT4601A typically con- sumes 12µA when operating; when off, the device draws less than 1µA. In the off state, current is pre- vented from flowing between the input and output. The ON function has logic level thresholds that allow the AAT4601A to be TTL compatible and may also be controlled by 2.5V to 5.0V CMOS circuits. The voltage level on either ON or FAULT should not exceed the input supply level present on the IN pin.

A simple three-step procedure can be used to adjust the AAT4601A's current limit. First, the max- imum current required by the load should be deter- mined. Second, select a resistor that guarantees adequate current is available to the load under nor- mal conditions. Finally, the maximum current that can pass through the switch can be calculated and compared to the maximum current available. Step 1: The maximum current required by a load is usually defined in port specifications design application references. For example, USB ports may be specified to support loads of up to 500mA. Step 2: The most convenient method for deter- mining a current limit resistor value is to look it up in Table 1, "Current Limit R SET Values." Find the lowest current value that is greater than the maxi- mum load current in the given application as listed in the column, "Device Will Not Current Limit Below." The resistor value needed is listed in the corresponding row in the column, "R SET." For example, a USB port requires 500mA. The lowest level where the device will current limit above 500mA is 507mA. The corresponding resistor value for R SET would be 33kΩ. Step 3: Now the required resistor value has been determined. The maximum current that can be drawn, even with a short circuit applied to the out- put, can be determined by reading the column, "Device Always Current Limits Below." If the power supply connected to the AAT4601A's input can pro- vide this current level, the power supply voltage will not collapse when a short circuit is applied to the load switch output. For example, a notebook com- puter has a USB port which is powered by an AAT4601A with a 33kΩ resistor connected between the SET pin and GND. If the power supply con- nected to the AAT4601A's IN pin can provide more than 845mA, this supply will remain in regulation even if a short circuit is applied to the USB port. Figure 1: Current Limit R SET Values. AAT4601A 1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 9 Current Device Will Not Device Always RSET Limit Current Limit Current Limits (kΩΩ) Typ (mA) Below (mA) Below (mA) 7.5 2476 1857 3095 8.2 2277 1708 2847 9.1 2065 1549 2581 10 1895 1421 2369 11 1748 1311 2185 12 1633 1224 2041 13 1528 1146 1910 15 1353 1015 1691 16 1280 960 1600 18 1158 869 1448 20 1055 791 1318 22 972 729 1215 24 897 673 1122 27 811 608 1014 30 736 552 919 33 676 507 845 36 625 469 781 39 582 436 727 43 533 400 666 47 491 368 613 51 455 341 568 56 418 314 523 62 380 285 476 68 350 262 437 75 320 240 400 82 295 221 369 91 267 200 334 100 245 183 306 110 223 167 279 120 206 155 258 130 192 144 239 150 167 125 209 160 157 118 197

1.8A Current Limited P-Channel Switch 10 4601A.2006.05.1.5 Operation in Current Limit If an excessive load is applied to the output of an AAT4601A, the load current will be limited by the device's current limit circuitry as shown in Figure 1, "Overload Operation." If a short circuit were to occur on the load, it would demand more current than allowed by the internal current limiting circuit and the voltage at the AAT4601A's output would drop. This causes the AAT4601A to dissipate more power than in normal operation, causing the die temperature to increase. When die temperature exceeds the internal over-temperature threshold, the AAT4601A will shut down. After shutting down, the AAT4601A cools to a level below the over-temperature threshold, at which point it will start up again. The AAT4601A will contin- ue to cycle off and on until one of the following events occurs: the load current is reduced to a level below the AAT4601A's current limit setting; the input power is removed; or the output is turned off by a logic high level applied to the ON pin. Thermal Considerations Since the AAT4601A has internal current limit and over-temperature protection, junction temperature is rarely a concern. If an application requires a large load current in a high-temperature operating envi- ronment, there is the possibility that the over-tem- perature protection circuit, rather than the current limit circuit, will regulate the current available to the load. In these applications, the maximum current available without risk of activation of the over-tem- perature circuit can be calculated. The maximum internal temperature while current limit is not active can be calculated using Equation 1: Eq. 1: In Equation 1, I MAX is the maximum current required by the load. R DS(ON)(MAX) is the maximum rated RDS(ON) of the AAT4601A at high temperature. RθJA is the thermal resistance between the AAT4601A's die and the board onto which it is mounted. T A(MAX) is the maximum ambient temperature for the printed circuit board assembly under the AAT4601A when the load switch is not dissipating power. Equation 1 can be transformed to provide I MAX; refer to Equation 2: Eq. 2: TSD(MIN) is the minimum temperature required to activate the AAT4601A's over-temperature protec- tion. With a typical specification of 125°C, 115°C is a safe minimum value to use. = IMAX TSD(MIN) - TA(MAX) RDS(ON)(MAX) × RΘJA TJ(MAX) = IMAX 2 × RDS(ON)(MAX) × RθJA + TA(MAX)Figure 1: Overload Operation. -0.5 0 0.5 1 1.5 2 Time (s) Voltage (V) Output Voltage Input Voltage 1Ω is Applied to Output at t = 0 RSET is 33kΩ

For example, a portable device is specified to oper- ate in a 50°C environment. The printed circuit board assembly will operate at temperatures as high as 85°C. This portable device has a sealed case and the area of the printed circuit board assembly is relatively small, causing R θJA to be approximately 120°C/W. Using Equation 2: Eq. 3: If this system requires less than 1.4A, the thermal limit will not activate during normal operation. Input Capacitor The input capacitor serves two purposes. First, it protects the source power supply from transient current effects generated by the application load circuit. If a short circuit is suddenly applied to the output of an AAT4601A, there is a microsecond- long period during which a large current can flow before the current limit circuitry activates; refer to the characteristic curve, "Short-Circuit Through 0.3Ω." A properly sized input capacitor can dramat- ically reduce the load switch input transient response effects seen by the power supply and other circuitry upstream from the AAT4601A. The second purpose of the input capacitor is to prevent transient events generated by the load cir- cuit from affecting operation of the AAT4601A. For example, if an AAT4601A is used in a circuit that operates from a 3V power supply with poor step load response, it is possible that turning on the load switch could cause the input power supply to droop below the AAT4601A's under-voltage lockout threshold. This drop in voltage would cause the AAT4601A to turn off until the input power supply's voltage recovers. Since this cycle would be self- perpetuating, the entire circuit could be seen to be unstable. In the very rare case where capacitor cost is prohibitive, the output load circuit should be slew rate limited when turned on. Output Capacitor In order to insure stability while the device current limit is active, a small capacitance of approximately 1µF should be used. When the AAT4601A is acti- vated using the ON function, there are no momen- tary current transients, as in the case when a short circuit is suddenly applied to a device that is already on; refer to the characteristic curve, "Switch Turn-On Time." No matter how big the output capacitor, out- put current is limited to the value allowed by the threshold determined by R SET and the internal cur- rent limiting circuitry. This permits very large output capacitors to be used. For example, USB ports are specified to have at least 120µF of downstream capacitance from their control- ling power switch. An output capacitance as large as 1000µF would not disturb the input power supply to the AAT4601A used to control the USB port. ON Input When the AAT4601A is in the off state, the output is an open circuit and the device quiecent current consumption is reduced to less than 1µA. The ON threshold voltage is set to allow the AAT4601A to be controlled by 5V TTL levels as well as CMOS power from 2.5V to 5V. The ON function control voltage level should not exceed the input supply level applied to the IN pin. FAULT Output A FAULT flag is provided to alert a system if the load switch is not receiving a sufficient voltage level to properly operate. If either the current limit or over- temperature circuits in any combination are contin- uously active for more than approximately 2ms, the FAULT pin is pulled to ground internally through a 100Ω resistance. The 2ms delay on the FAULT function is intended to prevent capacitive loads con- nected to the load switch output from activating FAULT when the device is turned on. The place- ment of a pull-up resistor between the FAULT pin and the IN pin is recommended. Reasonable val- ues for the pull-up resistor should range from 10kΩ to 100kΩ. Since FAULT is an open drain terminal, = IMAX = 1.4A115 - 85 130 · 120 AAT4601A 1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 11

1.8A Current Limited P-Channel Switch 12 4601A.2006.05.1.5 Figure 1: AAT4601A Evaluation Figure 2: AAT4601A Evaluation Figure 3: AAT4601A Evaluation Board Top Side Silk Screen Board Component Side Layout. Board Solder Side Layout. Assembly Drawing. it may be pulled up to any voltage that is not greater than the level present on the IN pin. This is done to allow the AAT4601A to signal ancillary circuitry that is powered by a voltage level less than the level on the IN pin. Reverse Voltage The AAT4601A is designed to control current flow- ing from IN to OUT. If a voltage is applied to OUT that is greater than that on IN, a large resulting reverse current may flow, potentially damaging the AAT4601A. Printed Circuit Board Layout Recommendations For proper thermal management, and to take advantage of the low R DS(ON) of the AAT4601A, 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. Evaluation Board Layout The AAT4601A evaluation layout follows the print- ed circuit board layout recommendations and can be used for good applications layout. Note: Board layout shown is not to scale.

Ordering Information

Package Information

All dimensions in millimeters. 0.175 ± 0.075 6.00 ± 0.20 1.27 BSC0.42 ± 0.09 × 8 4.90 ± 0.10 4° ± 4° 45°0.375 ± 0.125 0.235 ± 0.045 0.825 ± 0.445 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means Package Marking 1 Part Number (Tape and Reel)2 SOP-8 4601A AAT4601AIAS-T1 TSSOP-8 4601A AAT4601AIHS-T1 MSOP-8 MQXYY AAT4601AIKS-T1 AAT4601A 1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 13 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD.

All dimensions in millimeters. DETAIL A 4.40 ± 0.10 6.40 ± 0.20

0.65 BSC

3.00 ± 0.10 0.245 ± 0.055 × 8 0.10 ± 0.05 0.60 ± 0.15 0.145 ± 0.055

1.05 MAX

1.20 MAX 4° ± 4°

12° 12° REF × 4 1.00 REF AAT4601A 1.8A Current Limited P-Channel Switch 14 4601A.2006.05.1.5

All dimensions in millimeters. PIN 1

1.95 BSC

0.254 BSC

0.155 ± 0.075 0.60 ± 0.20 3.00 ± 0.10 0.95 ± 0.15

0.95 REF

0.85 ± 0.10 3.00 ± 0.10 10° ± 5° 4° ± 4° 0.65 BSC 0.30 ± 0.08 0.075 ± 0.075 4.90 ± 0.10 GAUGE PLANE AAT4601A 1.8A Current Limited P-Channel Switch 4601A.2006.05.1.5 15

1.8A Current Limited P-Channel Switch 16 4601A.2006.05.1.5 Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 © 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 sub- ject 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 con- trol 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 produ ct names appearing in this document are regis- tered trademarks or trademarks of their respective holders.