AAT4608 Current Limited Load Switch in SOT23 Package General Description Features The AAT4608 SmartSwitch is a member of AnalogicTech's Application Specific Power MOSFET™ (ASPM™) product family. It is a current limited P-channel MOSFET power switch designed for high-side load switching applications. This switch operates with inputs ranging from 2.7V to 5.5V, making it ideal for both 3V and 5V systems. An integrated current-limiting circuit protects the input supply against large currents which may cause the supply to fall out of regulation. The AAT4608 is also protected from thermal overload which limits power dissipation and junction temperatures. It can be used to control loads that require up to 1A. Current limit threshold is programmed with a resistor from SET to ground. The quiescent supply current is typically a low 15µA max. • • • • • • • • • • SmartSwitch™ 2.7V to 5.5V Input Voltage Range Programmable Over-Current Threshold Fast Transient Response: — <1µs Response to Short Circuit Low Quiescent Current — 15µA Typical — 1µA Max With Switch Off 160mΩ Typical RDS(ON) Under-Voltage Lockout Thermal Shutdown Temperature Range: -40°C to +85°C 4kV ESD Rating 5-Pin SOT23 Package Applications The AAT4608 is available in a Pb-free, 5-pin SOT23 package, and is specified over the -40°C to +85°C temperature range. • • • • Hot Swap Supplies Notebook Computers Peripheral Ports Personal Communication Devices Typical Application INPUT 5 IN AAT4608 OUTPUT 1 OUT SOT23 3 SET GND 1µF GND 4608.2006.03.1.3 2 RSET 0.47µF GND 1 AAT4608 Current Limited Load Switch in SOT23 Package Pin Descriptions Pin # Symbol Function 1 OUT P-channel MOSFET drain. Connect 0.47µF capacitor from OUT to GND. 2 GND Ground connection. 3 SET Current limit set input. A resistor from SET to ground sets the current limit for the switch. 4 N/C No internal connection. 5 IN P-channel MOSFET source. Connect 1µF capacitor from IN to GND. Pin Configuration SOT23-5 (Top View) 2 OUT 1 GND 2 SET 3 5 IN 4 N/C 4608.2006.03.1.3 AAT4608 Current Limited Load Switch in SOT23 Package Absolute Maximum Ratings1 TA = 25°C unless otherwise noted. Symbol Description VIN VSET, VOUT IMAX TJ TLEAD VESD IN to GND SET, OUT to GND Maximum Continuous Switch Current Operating Junction Temperature Range Maximum Soldering Temperature (at Leads) ESD Rating2 - HBM Value Units -0.3 to 6 -0.3 to VIN + 0.3 2 -40 to 150 300 4000 V V A °C °C V Value Units 150 667 °C/W mW Thermal Characteristics3 Symbol ΘJA PD Description Thermal Resistance Power Dissipation Electrical Characteristics VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Symbol VIN IQ VUVLO RDS(ON) ILIM ILIM(MIN) TRESP Description Operation Voltage Quiescent Current Under-Voltage Lockout On Resistance Current Limit Minimum Current Limit Current Limit Response Time Conditions Min Typ 2.7 VIN = 5V, IOUT = 0 Rising Edge, 1% Hysteresis VIN = 5.0V VIN = 4.5V VIN = 3.0V RSET = 6.8kΩ VIN = 5V 2.0 0.5 15 2.3 160 165 195 1 150 0.8 Max Units 5.5 30 2.7 180 V µA V mΩ 230 2.0 A mA µs 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 a demo board. 4608.2006.03.1.3 3 AAT4608 Current Limited Load Switch in SOT23 Package Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Quiescent Current 40 25 Input Current (µA) Quiescent Current (µA) Quiescent Current vs. Temperature 20 15 10 5 30 20 10 0 -40 -20 0 20 40 60 80 100 0 120 2.5 Temperature (C) 3 3.5 4 4.5 5 5.5 Input Voltage (V) RDS(ON) vs. Temperature Output Current vs. Output Voltage (RSET = 16kΩ) 250 200 RDS(ON) (mΩ) Output Current (A) 0.6 0.4 0.2 Input = 3V 150 Input = 5V 100 50 0 0 -40 0 1 2 3 4 -20 0 20 40 60 80 100 5 Temperature (°C) Output Voltage (V) 12 8 Input Voltage 4 4 Output Current 2 0 Output Voltage 0 -4 0 1 2 3 8 9 6 6 Input Voltage 4 3 Output Current 2 0 Output Voltage 0 Output Current (A) 6 Input and Output Voltage (V) 8 Time (µs) 4 Short Circuit Through 0.6Ω Output Current (A) Input and Output Voltage (V) Short Circuit Through 0.3Ω -3 0 1 2 3 Time (µs) 4608.2006.03.1.3 AAT4608 Current Limited Load Switch in SOT23 Package Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. RSET vs. ILIM RSET Coefficient vs. ILIM 10 RSET ILIM Product (kV) RSET (kΩ) 100 10 1 0.1 9 8 7 6 5 1 10 ILIM (A) 0 0.5 1 1.5 2 ILIM (A) Current Limit vs. Temperature Current Limit (%) 6 RSET = 22.1k VIN - VOUT = 0.5V 4 2 0 -2 -4 -6 -50 - 25 0 25 50 75 100 Temperature (°C) 4608.2006.03.1.3 5 AAT4608 Current Limited Load Switch in SOT23 Package Functional Block Diagram IN OUT Over-Temp Protection Undervoltage Lockout 1.2V Reference SET Current Limit RSET GND Applications Information Current Limit Using 10.5kΩ 1.2 Setting Current Limit 6 Device with high current limit at -40°C 0.88 A 1 0.8 ILIM (A) In most applications, the variation in ILIM must be taken into account when determining RSET. The ILIM variation is due to processing variations from part to part, as well as variations in the voltages at IN (Pin 5) and OUT (Pin 1), plus the operating temperature. See charts "Current Limit vs. Temperature," and "Output Current vs. VOUT." Together these three factors add up to a ±25% tolerance (see ILIM specification in Electrical Characteristics section). In the figure below, a cold device with a statistically higher current limit, and a hot device with a statistically lower current limit, both with RSET equal to 10.5kΩ, are shown. While the chart, "RSET vs. ILIM" indicates an ILIM of 0.7A with an RSET of 10.5kΩ, this figure shows that the actual current limit will be at least 0.525A, and no greater than 0.880A. 0.6 0.525 A 0.4 Device with low current limit at 85°C 0.2 0 0 1 2 3 4 5 VOUT (V) To determine RSET, start with the maximum current drawn by the load and multiply it by 1.33. (Typical_ILIM = minimum_ILIM / 0.75.) This is the typical current limit value. Next, refer to "RSET vs. ILIM" and find the RSET that corresponds to the typ- 4608.2006.03.1.3 AAT4608 Current Limited Load Switch in SOT23 Package ical current limit value. Choose the largest resistor available that is less than or equal to it. For greater precision, the value of RSET may also be calculated using the ILIM RSET product found in the chart "RSET coefficient vs. ILIM." The maximum current is derived by multiplying the typical current for the chosen RSET in the chart by 1.25. A few standard resistor values are listed in Table 1. RSET Ω) (kΩ Current Limit (Typ) (mA) Device Will Not Current Limit Below (mA) Device Always Current Limits Below (mA) 40.2 30.9 24.9 22.1 19.6 17.8 16.2 14.7 13.0 10.5 8.87 7.50 6.81 6.04 5.49 4.99 4.64 200 250 300 350 400 450 500 550 600 700 800 900 1000 1100 1200 1300 1400 150 188 225 263 300 338 375 413 450 525 600 675 750 825 900 975 1050 250 313 375 438 500 563 625 688 750 875 1000 1125 1250 1375 1500 1625 1750 Example: A USB port requires 0.5A. 0.5A multiplied by 1.33 is 0.665A. From the chart named "RSET vs. ILIM," RSET should be less than 11kΩ. 10.5kΩ is a standard value that is a little less than 11kΩ but very close. The chart reads approximately 0.700A as a typical ILIM value for 10.5kΩ. Multiplying 0.700A by 0.75 and 1.25 shows that the AAT4608 will limit the load current to greater than 0.525A, but less than 0.875A. Operation in Current Limit When a heavy load is applied to the output of the AAT4608, the load current is limited to the value of ILIM determined by RSET (see Figure 1). Since the load is demanding more current than ILIM, the voltage at the output drops. This causes the AAT4608 to dissipate a larger than normal quantity of power, and its die temperature to increase. When the die temperature exceeds an over-temperature limit, the AAT4608 will shut down until is has cooled sufficiently, at which point it will start up again. The AAT4608 will continue to cycle on and off until the load (or power) is removed. Reverse Voltage The AAT4608 is designed to control current flowing from IN to OUT. If a voltage is applied to OUT which is greater than the voltage on IN, large currents may flow. This could cause damage to the AAT4608. Table 1: Current Limit RSET Values. 1 0.5 0.25 0 5 Output Current 4 3 1Ω load is turned on at time = 0 Output Voltage 2 Output Current (A) Output Voltage (V) 0.75 1 0 -0.05 0 0.05 0.1 0.15 0.2 0.25 0.3 Time (s) Figure 1: Overload Operation. 4608.2006.03.1.3 7 AAT4608 Current Limited Load Switch in SOT23 Package Ordering Information Package Marking1 Part Number (Tape and Reel)2 SOT23-5 CMXYY AAT4608IGV-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 SOT23-5 2.85 ± 0.15 1.90 BSC 0.40 ± 0.10 0.075 ± 0.075 0.15 ± 0.07 4° ± 4° 10° ± 5° 1.10 ± 0.20 0.60 REF 1.20 ± 0.25 2.80 ± 0.20 1.575 ± 0.125 0.95 BSC 0.60 REF 0.45 ± 0.15 GAUGE PLANE 0.10 BSC All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. © 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 8 4608.2006.03.1.3