AAT4601 ANALOGICTECH

Document overview

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Technical content

Features

  • 2.7V to 5.5V Input voltage range
  • 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
  • Undervoltage Lockout
  • Temperature range -40 to 85°C
  • 2kV ESD rating
  • UL Approved—File No. E217765
  • 8-pin SOP or TSSOP package

Applications

  • USB ports
  • Notebook computers
  • Peripheral ports
  • Hot swap supplies UL Recognized Component AAT4601 1.5A Current Limited P-Channel Switch Typical Application AAT4601 ON IN OUT SET GND ON 1µF 100kΩ R SET 1uF INPUT OUTPUT IN OUT FAULT Preliminary Information 4601.2001.11.0.92 1

(Top View) 1 2 IN ON GND FAULT OUT OUT SET IN 1 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 +135 ºC, with a 2ms delay after the fault event occurs. AAT4601 1.5A Current Limited P-Channel Switch 2 4601.2001.11.0.92

1.5A Current Limited P-Channel Switch 4601.2001.11.0.92 3 Absolute Maximum Ratings (TA=25°C unless otherwise noted) Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at con- ditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time. Note 1: Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. Thermal Characteristics Note 2: Mounted on an AATI demo board. Electrical Characteristics (VIN = 5V, TA = -40 to 85°C unless otherwise noted. Typical values are at TA=25°C) Note 3: Guaranteed by design. 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 .004 1 µA ISD(OFF) Off Switch Current ON = IN, V IN = 5.5V, VOUT = 0 .07 15 µA VUVLO Undervoltage Lockout Rising edge, 1% hysteresis, 2.0 2.3 2.7 V VIN=5.0V 70 m Ω RDS(ON) On-Resistance V IN=4.5V 75 130 m Ω VIN=3.0V 80 150 m Ω ILIM Current Limit R SET = 2kΩ 510 715 920 mA ILIM(MIN) Minimum Current Limit 250 mA TSD 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 V 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 Time3 VIN=5V 20 µs TON Turn-On Time3 VIN=5V 200 µs OTMP Over Temperature Shut Down 125 ºC Symbol Description Value Units ΘJA Typical Thermal Resistance2 100 °C/W PD Maximum Power Dissipation2 1.25 W 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—HBM1 4000 V

(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-SupplyCurrent vs. Temperature 0.0001 0.001 0.01 0.1 - 4 0 - 2 00 2 04 06 08 0 1 0 0 1 2 0 1 4 0 Temperature Off-Supply Current (µA) (°C) RSET ILIM Product vs ILIM 500 1000 1500 2000 2500 0 0.5 1 1.5 2 Typical ILIM (A) Product (V) Current Limit 0.2 0.4 0.6 0.8 01 2345 Output (V) Output (A) RSET = 2 k/K57 Input Voltage = 5 V 0123456 Quiescent Current Input (V) Input (µA) Quiescent Current vs. Temperature -40 -20 0 20 40 60 80 100 120 Temperature Quiescent Current (µA) (°C) AAT4601 1.5A Current Limited P-Channel Switch 4 4601.2001.11.0.92

(Unless otherwise noted, VIN = 5V, TA = 25°C) ShortCircuitthrough 0.6 Ω -20 0 20 40 60 80 100 120 140 Time (µs) Input and Output Output (A) Output Current Input Voltage Output Voltage (V) Short Circuit through 0.3Ω 02468 Time (µs) Input and Output Output (A) Output Current Input Voltage Output Voltage (V) Switch Turn-OffTime - 4 - 20246 Time ( Voltage (V) Output ONIOUT =I LIMIT Switch Turn-On Time -20 -10 0 40 60 80 Time ( Voltage (V) Output ON IOUT =ILIMIT Turn-Off vs. Temperature 0.2 0.4 0.6 0.8 1.8 1.6 1.4 1.2 -40 -20 0 20 40 60 80 100 120 Temperature (°C) Turn-OFF Time (µs) VIN=5V VIN=3V Turn-On vs. Temperature -40 -20 0 20 40 60 80 100 120 Temperature (°C) Turn-ON Time (µs) VIN=3V VIN=5V AAT4601 1.5A Current Limited P-Channel Switch 4601.2001.11.0.92 5

(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 1.5 2.0 2.5 -40 -20 0 20 40 60 80 100 Temperature (°C) Fault Delay (ms) AAT4601 1.5A Current Limited P-Channel Switch 6 4601.2001.11.0.92

1.2V Reference Current Limit AAT4601 1.5A Current Limited P-Channel Switch 4601.2001.11.0.92 7 Functional Description The AAT4601 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 AAT4601 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 the current limit or over temperature protection circuits are active for more then two milliseconds, the system will be informed via the FAULT Flag. The two millisecond delay allows the AAT4601 to be turned on into capacitive loads without activat- ing the FAULT Flag. The open drain FAULT output can be connected directly 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 AAT4601 typically con- sumes 12µA when operating, when off, the device draws less then 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 AAT4601 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 AAT4601's current limit. First, the maxi- mum 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 are specified to support loads of up to 500 mA. Step 2: The most convenient method for deter- mining a current limit resistor value is to look it up in the provided table named "Current Limit R SET Values". Find the lowest current value that is greater than the maximum load current in the given application. Refer to the column named "Device will not current limit below". The resistor value needed is in the corresponding row named "R SET". For example, a USB port requires 500 mA. The lowest level where the device will current limit above 500 mA is 516 mA. The corresponding resistor value for R SET would be 2kΩ . 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 labeled "Device always current limits below". If the power supply connected to the AAT4601's input can provide 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 AAT4601 with a 2k Ω resistor connected between the SET pin and GND. If the power supply con- nected to the AAT4601's IN pin can provide more than 917 mA, this supply will remain in regulation even if a short circuit is applied to the USB port. Current Limit RSET Values AAT4601 1.5A Current Limited P-Channel Switch 8 4601.2001.11.0.92 RSET Current Device will Device always (Ω ) Limit typ not current current limits (mA) limit below: below: (mA) (mA) 470 1585 1141 2029 510 1529 1101 1957 560 1466 1055 1876 620 1397 1006 1788 680 1334 960 1707 750 1266 911 1620 820 1206 869 1544 910 1144 823 1464 1000 1089 784 1394 1100 1034 745 1324 1200 986 710 1262 1300 941 677 1204 1500 865 623 1107 1600 829 597 1061 1800 769 554 985 2000 716 516 917 2200 673 485 861 2400 633 456 811 2700 582 419 745 3000 539 388 690 3300 502 362 643 3600 470 339 602 3900 442 318 565 4300 410 295 524 4700 382 275 489 5100 358 258 458 5600 332 239 424 6200 306 220 392 6800 283 204 362 7500 268 193 343

1.5A Current Limited P-Channel Switch 4601.2001.11.0.92 9 Applications Information Operation in Current Limit If an excessive load is applied to the output of an AAT4601, the load's current will be limited by the AAT4601's current limit circuitry. Refer to the figure named "Overload Operation". If a short circuit were to occur on the load, it would demand more current than what is allowed by the internal current limiting circuit and the voltage at the AAT4601's output will drop. This causes the AAT4601 to dissipate more power than in normal operation, causing the die tem- perature to increase. When die temperature exceeds the internal over temperature threshold, the AAT4601 will shut down. After shutting down, the AAT4601 cools to a level below the over temperature thresh- old, at which point it will start up again. The AAT4601 will continue to cycle off and on until one of the fol- lowing events occurs; the load current is reduced to a level below the AAT4601's current limit setting, the input power is removed, or until the output is turned off by a logic high level applied to the ON pin. Thermal Considerations Since the AAT4601 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: T J(MAX) = IMAX 2 × RDS(ON)(MAX) × RθJA + TA(MAX) In Equation 1, IMAX is the maximum current required by the load. R DS(ON)(MAX) is the maximum rated RDS(ON) of the AAT4601 at high temperature. RθJA is the thermal resistance between the AAT4601'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 AAT4601 when the load switch is not dissipating power. Equation 1 can be transformed to provide I MAX; Refer to Equation 2. IMAX= TSD(MIN) - TA(MAX) RDS(ON)(MAX) × RθJA TSD(MIN) is the minimum temperature required to activate the AAT4601's over temperature protec- tion. With typical specification of 125°C, 115°C is a safe minimum value to use. 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 board assembly is rellatively small causing R θJA to be approximately 120°C/W. Using Equation 2, IMAX= 115 - 85 = 1.4 A130 × 120 If this system requires less than 1.4 A, the thermal limit will not activate during normal operation. Overload Operation -0.5 0 0.5 1 1.5 2 Time (s) Voltage (V) Output Voltage Input Voltage 1 /K57/K0 is applied to output at t = 0 RSET is 2 k/K57

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 AAT4601, there is a microsecond long period during which a large can current flow before the current limit circuitry activates. Refer to the characteristic curve named "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 AAT4601. The second purpose of the input capacitor is to prevent transient events generated by the load cir- cuit from affecting the operation of the AAT4601. For example, if an AAT4601 is used in a circuit that operates from a 3 volt 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 AAT4601's under voltage lockout thresh- old. This drop in voltage would cause the AAT4601 to turn off until the input power supply's voltage recovers. Since this cycle would be self-perpetuat- ing, the entire circuit could be seen to be unstable. In the very rare case where capacitor cost is pro- hibitive, 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 AAT4601 is activat- ed using the ON function, there are no momentary current transients as in the case of when a short cir- cuit suddenly applied to a device that is already on. Refer to the characteristic curve named "Switch Turn-On Time." No matter how big the output capacitor, output current is limited to the value allowed by the threshold determined by R SET and the internal current limiting circuitry. This permits very large output capacitors to be used. For example, USB ports are specified to have at least 120µF of down stream capacitance from their controlling power switch. An output capacitance as large as 1000µF would not disturb the input power supply to the AAT4601 used to control the USB port. ON Input When the AAT4601 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 AAT4601 to be controlled by 5 volt TTL levels as well as CMOS power from 2.5 volts to 5 volts. 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 operate properly. If either the current limit or over temperature circuits in any combination are active for more than approximately two milliseconds con- tinuously, the FAULT pin is pulled to ground inter- nally through a 100Ω resistance. The 2 millisecond delay on the FAULT function is intended to prevent capacitive loads connected to the load switch out- put from activating FAULT when the device is turned on. The placement of a pull up resistor between the FAULT pin and the IN pin is recom- mended. Reasonable values for the pull up resistor should range from 10kΩ to 100kΩ. Since FAULT is an open drain terminal, 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 AAT4601 to sig- nal ancillary circuitry that is powered by voltage level less than the level on the IN pin. Reverse Voltage The AAT4601 is designed to control current flowing from IN to OUT. If a voltage is applied to OUT which is greater than that on IN, a large resulting reverse current may flow, potentially damaging the AAT4601. AAT4601 1.5A Current Limited P-Channel Switch 10 4601.2001.11.0.92

1.5A Current Limited P-Channel Switch 4601.2001.11.0.92 11 Figure 1: AAT4601 Evaluation Figure 2: AAT4601 Evaluation Figure 3: AAT4601 Evaluation board top side silk screen board component side layout board solder side layout assembly drawing Printed Circuit Board Layout Recommendations For proper thermal management, and to take advantage of the low RDS(ON) of the AAT4601, a few circuit board layout rules should be followed: V IN and VOUT 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 AAT4601 evaluation layout follows the printed circuit board layout recommendations, and can be used for good applications layout. Note: Board layout shown is not to scale.

Ordering Information

Package Information

E b e H D A 7(4x) c Ly Q Package Marking Part Number Bulk Tape and Reel SOP-8 AAT4601IAS-B1 AAT4601IAS-T1 TSSOP-8 AAT4601IHS-B1 AAT4601IHS-T1 AAT4601 1.5A Current Limited P-Channel Switch 12 4601.2001.11.0.92 Dim Millimeters Inches Min Max Min Max A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.004 0.010 A2 1.45 0.057 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 e 1.27 0.050 H 5.80 6.20 0.228 0.244 L 0.40 1.27 0.016 0.050 Y 0.00 0.10 0.000 0.004 θ10 ° 8 ° 0 ° 8 ° Note: 1. PACKAGE BODY SIZES EXCLUDE MOLD FLASH PROTRUSIONS OR GATE BURRS. 2. TOLERANCE± 0.1000mm (4mil) UNLESS OTHERWISE SPECIFIED 3. COPLANARITY: 0.1000mm 4. DIMENSION L IS MEASURED IN GAGE PLANE. 5. CONTROLLING DIMENSION IS MILLIMETER; CONVERTED INCH DIMENSIONS ARE NOT NECESSARILY EXACT.

b e E 1 2 AA2 E1 DETAIL A R L 0.20 D E DETAIL A AAT4601 1.5A Current Limited P-Channel Switch 4601.2001.11.0.92 13 Dim Millimeters Inches Min Max Min Max A 1.05 1.20 0.041 0.047 A1 0.05 0.15 0.002 0.006 A2 - 1.05 - 0.041 b 0.25 0.30 0.010 0.012 c 0.127 0.005 D-8 2.90 3.10 0.114 0.122 D-28 9.60 9.80 0.378 0.386 E 4.30 4.50 0.170 0.177 E1 6.20 6.60 0.244 0.260 e 0.65 BSC 0.025 BSC L 0.50 0.70 0.20 0.028 L1 1.0 0.039 R 0.09 - 0.004 - R1 0.09 - 0.004 - θ10 ° 8 ° 0 ° 8 ° θ2 12°

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