AAT4618 Current Limited Load Switch General Description Features The AAT4618 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 operating with inputs ranging from 2.4V to 5.5V, making it ideal for 2.5V, 3V, and 5V systems. An integrated currentlimiting circuit protects the input supply from large currents which may cause the supply to fall out of regulation. In addition, the AAT4618 thermal overload protection limits power dissipation and junction temperatures associated with prolonged periods of operation in current limit. Due to its low RDS(ON), the AAT4618 can be used to control loads that require up to factory preset 400mA, 500mA, or 1A. The ultra-fast current limit response to a sudden short circuit is a mere 400ns which reduces the requirements of local supply bypassing. An open drain FAULT flag signals an over-current or over-temperature condition after a 4ms timeout. Quiescent current is a low 10µA and the supply current decreases to less than 1µA in shutdown mode. • • • • • • • • • • • SmartSwitch™ 2.4V to 5.5V Input Voltage Range Current Limit Trip Threshold Options: — 400mA Min — 500mA Min — 1A Min Fast Transient Response: — 400ns Response to Short Circuit Low Quiescent Current: — 10µA Typical — < 1µA with Switch Off 125mΩ Typical RDS(ON) FAULT Flag with 4ms Blanking Under-Voltage Lockout Thermal Shutdown Temperature Range: -40°C to +85°C 4kV ESD Rating 5-Pin SOT23 or 8-Pin SC70JW Package Applications • • • • • The AAT4618 is available in a Pb-free 5-pin SOT23 or a 8-pin SC70JW package and is specified over the -40°C to +85°C temperature range. The AAT4600 series is a family of adjustable and fixed voltage SmartSwitch products with a range of current handling capabilities. Single versions with adjustable current limit (AAT4610, AAT4601) or fixed current limit (AAT4625) are available, as well as dual versions with fixed current limit (AAT4626, AAT4670). Hot Swap Supplies Notebook Computers Peripheral Ports Personal Communication Devices USB Ports Typical Application INPUT OUTPUT IN OUT AAT4618 100k FAULT CIN 1μF GND 4618.2006.05.1.2 ON (ON) ON (ON) GND FAULT COUT 0.47μF GND 1 AAT4618 Current Limited Load Switch Pin Descriptions Pin # SOT23-5 SC70JW-8 Symbol Function 1 5 OUT P-channel MOSFET drain. 2 6, 7, 8 GND Ground connection. 3 1 FAULT 4 2 ON (ON) 5 3, 4 IN Open-drain FAULT output. Enable input: AAT4618 active low, AAT4618-1 active high. P-channel MOSFET source. Pin Configuration SOT23-5 (Top View) 5 IN 2 3 4 ON (ON) FAULT ON (ON) IN IN 1 8 7 2 2 2 1 1 OUT GND FAULT SC70JW-8 (Top View) 3 6 4 5 GND GND GND OUT 4618.2006.05.1.2 AAT4618 Current Limited Load Switch Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol Description VIN, FAULT VON VOUT IOUT TJ VESD TLEAD IN, FAULT to GND ON (ON) to GND OUT to GND Output Current Operating Junction Temperature Range ESD Rating2—HBM Maximum Soldering Temperature (at Leads) Value Units -0.3 to 6 -0.3 to VIN + 1 -0.3 to VIN + 0.3 Internally Limited -40 to 150 4000 300 V V V A °C V °C Value Units 150 667 °C/W mW Thermal Characteristics3 Symbol ΘJA PD Description Maximum Thermal Resistance Maximum Power Dissipation 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. 4618.2006.05.1.2 3 AAT4618 Current Limited Load Switch Electrical Characteristics VIN = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C; bold values denote full temperature range. Symbol VIN IQ IQ(OFF) ISD(OFF) VUVLO VUVLO(hys) Description Operation Voltage Quiescent Current Off Supply Current Off Switch Current Under-Voltage Lockout Under-Voltage Lockout Hysteresis RDS(ON) On Resistance TCRDS On Resistance Temperature Coefficient ILIM VON(L) 10 0.1 1.9 VIN = 5.0V, TA = 25°C VIN = 3.0V, TA = 25°C Max Units 5.5 25 1 1 V µA µA µA V 125 155 V 175 225 2800 VIN = 2.7V to 5.5V1 VIN = 2.7V to ≤ 4.2V1 VIN = > 4.2V to 5.0V1 VON (ON) = 5.5V VIN = 5V VIN = 5V, RL = 20Ω VIN = 5V, RL = 20Ω ISINK = 1mA ON (ON) Input Leakage Current Loop Response Turn-Off Time Turn-On Time FAULT Logic Output Low FAULT Logic Output High Leakage Current Fault Blanking Time Over-Temperature Threshold Typ 0.3 ON (ON) Input Low Voltage ION(SINK) tRESP TOFF TON VFAULTLOW Tblank TSD VIN = 5V, ON (ON) = Active, IOUT = 0 ON (ON) = Inactive, VIN = 5.5V ON (ON) = Inactive, VIN = 5.5V, VOUT = 0 VIN Falling VOUT = VIN to 0.5V ON (ON) Input High Voltage Min 2.4 Current Limit VON(H) ISINK Conditions AAT4618-0.4 AAT4618-0.5 AAT4618-1.0 400 500 500 750 1000 1500 ppm/°C 600 1000 2000 0.8 VFAULT = 5.5V 0.5 VIN = 5V 4 125 mA 0.4 V V V µA ns µs µs V 1 µA 2.0 2.4 0.01 400 5 1 mΩ 1 ms °C 1. For VIN outside this range, consult Typical ON (ON) Threshold curve. 4 4618.2006.05.1.2 AAT4618 Current Limited Load Switch Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Quiescent Current vs. Input Voltage Quiescent Current vs. Temperature 20 Quiescent Current (μA) Quiescent Current (μA) 20 15 10 5 0 -40 -20 0 20 40 60 80 100 15 10 5 0 0 120 1 2 1.2 220 200 180 160 1 0.8 0.6 0.4 0.2 0 2 3 4 140 120 100 80 60 VIN = 5V 40 20 0 -40 5 -20 0 20 40 60 80 100 120 Temperature (°C) Off-Supply Current vs. Temperature Off-Switch Current vs. Temperature 1.00 1.00 Off-Switch Current (μA) Off-Supply Current (μA) 6 VIN = 3V Output Voltage (V) 0.10 0.01 0.00 -40 5 RDS(ON) vs. Temperature RDS(ON) (mΩ) Normalized Current Limit Normalized Current Limit vs. Output Voltage 1 4 Input Voltage (V) Temperature (°C) 0 3 -20 0 20 40 60 Temperature (°C) 4618.2006.05.1.2 80 100 120 0.10 0.01 0.00 -40 -20 0 20 40 60 80 100 120 Temperature (°C) 5 AAT4618 Current Limited Load Switch Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25°C. Turn-Off (RL = 20Ω; CL = 0.47µF) 6 5 5 ON 3 Voltage (V) 6 4 Voltage (V) Turn-On (RL = 20Ω; CL = 0.47µF) OUT 2 1 4 ON 3 OUT 2 1 0 0 -1 -1 -0.5 0.0 0.5 1.0 1.5 -10 2.0 0 10 10 Output Current 8 Output Voltage 3 6 2 4 1 2 0 Output Voltage (5V/div) Output Current (1A/div) 0 -1 0 1 2 50 12 Input Voltage 4 40 Thermal Shutdown Response Output Current (A) Input and Output Voltage (V) Short Circuit Through 0.3Ω 5 30 Time (µs) Time (µs) 6 20 3 4 5 Time (µs) Time (50ms/div) ON (ON) Threshold vs. Input Voltage Fault Delay from Short Circuit Output Voltage (5V/div) Output Current (1A/div) FAULT (5V/div) ON (ON) Threshold (V) 2.4 2.2 2 1.8 VON(H) 1.6 1.4 VON(L) 1.2 1 0.8 0.6 0.4 2 Time (1ms/div) 6 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) 4618.2006.05.1.2 AAT4618 Current Limited Load Switch Functional Block Diagram IN OUT Under-Voltage Lockout Over-Temperature Protection Current Limit FAULT ON (ON) 4ms Delay GND Functional Description The AAT4618 is a single channel current limited load switch that protects against short circuits by current limiting to a preset level. A patented fastacting current limit loop limits the current in a fraction of a microsecond and instantly resets to low impedance once the short-circuit condition is removed. The AAT4618 is internally protected from thermal damage by an over-temperature detection circuit. If the die temperature reaches the internal thermal limit, the power device is switched off until the die temperature cools to a level below the thermal limit threshold. The device will thermal cycle indefinitely until the over-current condition is removed. The AAT4618 operates with 4618.2006.05.1.2 input voltages ranging from 2.4V to 5.5V which, along with its extremely low operating current, makes it ideal for battery-powered applications. In cases where the input voltage drops below 2.4V, the AAT4618 MOSFET is protected from entering the saturated region of operation by being automatically shut down by an under-voltage lockout circuit. A current limit condition is reported by the open drain FAULT output. A 4ms blanking interval prevents false reporting during the charging of a capacitive load, which typically occurs during device turn-on, but may also occur during a port hot plug-in event. The AAT4618 is ideally suited for protection of peripheral ports such as USB, RS232, and parallel ports. 7 AAT4618 Current Limited Load Switch Applications Information Input Capacitor The input capacitor CIN protects the power supply from current transients generated by the load attached to the AAT4618. When a short circuit is suddenly applied to the output of the AAT4618, a large current, limited only by the RDS(ON) of the MOSFET, will flow for less than 1µs before the current limit circuitry activates. (See characteristic curve "Short Circuit Through 0.3Ω.") In this event, a moderately sized CIN will dramatically reduce the voltage transient seen by the power supply and by other circuitry upstream from the AAT4618. The extremely fast short-circuit response time of the AAT4618 reduces the size requirement of CIN. CIN should be located as close to the device VIN pin as practically possible. Ceramic, tantalum, or aluminum electrolytic capacitors are appropriate for CIN. There is no specific capacitor ESR requirement for CIN. However, for higher current operation, 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 In order to insure stability while current limit is active, a low capacitance (approximately 0.47µF) is required. No matter how large the output capacitor, output current is limited to the value set by the AAT4618 current limiting circuitry, so very large output capacitors can be used. For example, USB ports are specified to have at least 120µF of capacitance downstream from their controlling power switch. The current limiting circuit will allow an output capacitance of 1000µF or more without disturbing the upstream power supply. ON (Enable Input) In many systems, power planes are controlled by integrated circuits which run at lower voltages than the power plane itself. The enable input (ON) of the AAT4618 has low and high threshold voltages that accommodate this condition. The threshold voltages are compatible with 5V TTL and 2.5V to 5V CMOS systems. 8 When switching the AAT4618 on into a capacitive load, the AAT4618 will charge the output capacitive load at a rate no greater than the current limit setting. Attaching Loads Capacitive loads attached to an enabled AAT4618 will charge at a rate no greater than the current limit setting. FAULT Output The FAULT flag is provided to alert the system if an AAT4618 load is not receiving sufficient voltage to operate properly. If current limit or over-temperature circuits in any combination are active for more than approximately 4ms, the FAULT flag is pulled to ground through approximately 100Ω. The filtering of voltage or current transients of less than 4ms prevents capacitive loads connected to the AAT4618 output from activating the FAULT flag when they are initially attached. Pull-up resistances of 1kΩ to 100kΩ are recommended. Since FAULT is an open drain terminal, it may be pulled up to any unrelated voltage less than the maximum operating voltage of 5.5V, allowing for level shifting between circuits. Thermal Considerations Since the AAT4618 has internal current limit and over-temperature protection, junction temperature is rarely a concern. However, if the application requires large currents in a hot environment, it is possible that temperature, rather than current limit, will be the dominant regulating condition. In these applications, the maximum current available without risk of an over-temperature condition must be calculated. The maximum internal temperature while current limit is not active can be calculated using Equation 1. Eq. 1: TJ(MAX) = IMAX2 · RDS(ON)(MAX) · RΘJA + TA(MAX) In Equation 1, IMAX is the maximum current required by the load. RDS(ON)(MAX) is the maximum rated RDS(ON) of the AAT4618 at high temperature. RθJA is the thermal resistance between the AAT4618 die and the board onto which it is mounted. TA(MAX) is the maximum temperature that the PCB under the 4618.2006.05.1.2 AAT4618 Current Limited Load Switch AAT4618 would be if the AAT4618 were not dissipating power. Equation 1 can be rearranged to solve for IMAX, as shown in Equation 2. Eq. 2: IMAX = For example, if an application is specified to operate in 50°C environments, the PCB operates at temperatures as high as 85°C. The application is sealed and its PCB is small, causing RθJA to be approximately 150 °C/W. Using Equation 2, TSD(MIN) - TA(MAX) RDS(ON)(MAX) · RΘJA Eq. 3: IMAX = TSD(MIN) is the minimum temperature required to activate the AAT4618 over-temperature protection. With the typical specification of 125°C, 115°C is a safe minimum value to use. 4618.2006.05.1.2 115 - 85 = 950mA 220 · 150 The AAT4618 is safe to operate at the minimum current limit level of 500mA at 85°C. 9 AAT4618 Current Limited Load Switch Ordering Information Package Enable Current Limit Marking1 Part Number (Tape and Reel)2 SOT23-5 SOT23-5 SOT23-5 SOT23-5 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 Active Low Active High Active Low Active High Active Low Active High Active Low Active High Active Low Active High 0.5 0.5 1.0 1.0 0.4 0.4 0.5 0.5 1.0 1.0 AVXYY DWXYY EVXYY EIXYY AAT4618IGV-0.5-T1 AAT4618IGV-0.5-1-T1 AAT4618IGV-1.0-T1 AAT4618IGV-1.0-1-T1 AVXYY DWXYY EVXYY EIXYY AAT4618IJS-0.5-T1 AAT4618IJS-0.5-1-T1 AAT4618IJS-1.0-T1 AAT4618IJS-1.0-1-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 all part numbers listed in BOLD. 10 4618.2006.05.1.2 AAT4618 Current Limited Load Switch SC70JW-8 2.20 ± 0.20 1.75 ± 0.10 0.50 BSC 0.50 BSC 0.50 BSC 0.225 ± 0.075 2.00 ± 0.20 0.100 7° ± 3° 0.45 ± 0.10 4° ± 4° 0.05 ± 0.05 0.15 ± 0.05 1.10 MAX 0.85 ± 0.15 0.048REF 2.10 ± 0.30 All dimensions in millimeters. © 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. 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 4618.2006.05.1.2 11