PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag General Description Features The AAT4614 SmartSwitch is a current limited P-channel MOSFET power switch designed for high side load switching applications. This switch operates with inputs ranging from 2.4V 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. Reverse current blocking is provided to protect the load switch from reverse current potentials while the device is shutdown. * Input Voltage Range: 2.4V to 5.5V * Programmable Over-Current Threshold * Fast Transient Response: 1s Response to Short Circuit * Low Quiescent Current 10A Typical while Enabled 1A Max with Switch Off (TA = 25C) * 130m Typical RDS(ON) * Only 2.4V Needed for ON/OFF Control * Under-Voltage Lockout * Reverse Blocking During Disable * 4ms Fault Blanking * Fault Flag Open Drain Output (Not Available for SOT23-5 Package) * Active Hi/Lo Enable Options * Over-Temperature Protection * 4kV ESD Rating * 6-Pin SOT23, 5-Pin SOT23,or 8-Pin SC70JW Package * Temperature Range: -40C to +85C The AAT4614 is also protected from thermal overload which is limited by power dissipation and junction temperatures. Current limit threshold is programmed with a resistor from SET to ground and may be adjusted for levels up to 1.4A. The ultra-fast current limit response to a sudden short circuit is a mere 1s which reduces the requirements of local supply bypassing. An open drain FAULT flag signals an over-current or over-temperature condition after a 4ms blanking time to prevent false reporting. Quiescent current is a low 10A and the supply current decreases to less than 1A in shutdown mode. The AAT4614 is offered in the small Pb-free, 8-pin SC70JW, SOT23-6 and SOT23-5 packages, and is specified for operation over the -40C to +85C ambient temperature range. Applications * * * * * Hot Swap Supplies Notebook Computers Portable Products Proprietary Peripheral Ports USB Ports Typical Application Power Supply Input Output IN 1F EN/EN AAT4614 OUT ON/ON 0.47F 100k SET GND FLT Fault Flag RSET 4614.2009.10.1.3 www.analogictech.com 1 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Pin Description Pin # SOT23-6 SOT23-5 SC70JW-8 Symbol 1 1 5 OUT 2 2 6,7,8 GND 3 n/a 1 FLT 4 4 2 ON/ON 5 3 3 SET 6 5 4 IN Description Current limiting load switch output (high side P-channel MOSFET Drain). Connect a 0.47F capacitor from OUT to GND for best load transient response. IC ground connection Current limit fault flag pin, open-drain output, active low signal. Pull up with a 10k to 100k resistor. Load switch enable input. Active high and active low options are available. Current limit set pin. Connect a resistor between this pin and ground to program the desired current limit set point. Load switch power supply input pin (high side P-channel MOSFET source). Bypass with a 1F capacitor from IN to GND. Pin Configuration SOT23-6 (Top View) SOT23-5 (Top View) OUT 1 6 IN OUT 1 GND 2 5 SET GND 2 FLT 3 4 ON/ON SET 3 5 IN 4 ON/ON SC70JW-8 (Top View) FLT ON/ON SET IN 2 1 8 2 7 3 6 4 5 GND GND GND OUT www.analogictech.com 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Absolute Maximum Ratings1 Symbol Description VIN VON,VFLT VOUT, VSET IMAX VESD TJ TLEAD IN to GND ON/ON, FLT to GND OUT, SET to GND Maximum DC Output Current2 ESD Rating, HBM Maximum Junction Operating temperature Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6 -0.3 to VIN + 0.3 -0.3 to VIN + 0.3 2000 4000 -40 to +150 300 V V V mA V C C Value Units 625 667 150 160 mW mW C/W C/W Thermal Information Symbol PD JA Package SOT23-6(-5) SC70JW8 SOT23-6(-5) SC70JW8 Description Maximum Power Dissipation2,3 Maximum Thermal Resistance3 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. Mounted on FR4 circuit board. 3. Derate 6.25mW/C above 40C ambient temperature 4614.2009.10.1.3 www.analogictech.com 3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Electrical Characteristics VIN = 5V; TA = -40C to 85C unless otherwise noted. Typical values are at TA = 25C. Symbol Description Conditions Input Voltage Range Operation Quiescent Current Off Supply Current Off Switch Current Under-Voltage Lockout Under-Voltage Lockout Hysteresis VIN = 5V, ON/ON = Active, IOUT = 0 ON/ON = Inactive, VIN = 5.5V ON/ON = Inactive, VIN = 5.5V, TA = 25C Rising edge RDS(ON) On-Resistance VIN = 5.0V, TA = 25C VIN = 3.0V, TA = 25C TCRDS ILIM ILIM(MIN) VON(L) On-Resistance Temperature Coefficient Current Limit Minimum Current Limit ON/ON Input Low Voltage VIN IQ IQ(OFF) ISD(OFF) VUVLO VUVLO_HYS VON(H) ION(SINK) TRESP TON TOFF TSD TBLANK VFLT(LO) IFLT(SINK) 4 Typ 2.4 RSET = 6.8k; VOUT = VIN - 0.5V Input Leakage Current Current Limit Response Time Turn On Time Turn Off Time VIN = 2.7V to 5.5V VIN = 2.7V to <4.2V VIN 4.2V to 5.5V VON = 5.5V VIN = 5V VIN = 5V; RO = 10 VIN = 5V; RO = 10 Over-Temperature Shutdown Threshold VIN = 5V Fault Flag Blanking Time Fault Flag Logic Low Output Fault Flag Logic High Leakage Current IFLT(SINK) = 1mA ON/ON Input High Voltage Min 0.75 10 0.01 0.01 1.8 0.1 130 150 2800 1 130 Max Units 5.5 25 1 1 2.4 V A 180 230 m 1.25 ppm/C A mA V 0.6 V 2.0 2.4 TJ Increasing TJ Decreasing 0.01 1 12 55 125 115 4 0.5 www.analogictech.com 1 A 200 100 s C 0.4 1 ms V A 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25C, RSET = 6.8K. Quiescent Current vs. Temperature Output Current vs. Output Voltage (RSET = 6.8K) Normalized Current Limit (A) 20 IQ (A) 15 10 5 0 -40 -15 10 35 60 1.4 1.2 1 0.8 0.6 0.4 0.2 0 85 0 1 3 4 5 Output Voltage (V) Temperature (C) Quiescent Current vs. Input Voltage Off-Switch Current vs. Temperature 4 Off-Switch Current (A) 20 15 IQ (A) 2 10 5 1 2 3 4 5 2 1 0 -40 0 0 3 6 Input Voltage (V) -15 10 35 60 85 Temperature (C) RSET vs. ILIM RDS(ON) vs. Temperature 220 100 200 160 140 RSET (k) RDS(ON) (m) 180 120 100 80 10 60 40 VIN = 3V VIN = 5V 20 0 -40 -15 10 35 60 85 1 100 Temperature (C) 4614.2009.10.1.3 1000 10000 ILIM (mA) www.analogictech.com 5 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Typical Characteristics Unless otherwise noted, VIN = 5V, TA = 25C, RSET = 6.8K. ON(ON) Threshold vs. Input Voltage Turn-On (RL = 20; CL = 0.47F) ON(ON) Threshold (V) 2.4 2.2 VOUT (2V/div) 2 1.8 1.6 0 1.4 1.2 1 0.8 ON (2V/div) VON(ON)-Hi VON(ON)-Lo 0.6 0 0.4 2 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) Time (10s/div) Turn-Off Short Circuit Through 0.3 Resistor (VIN = 5.0V; RL = 20; CL = 0F) VOUT (2V/div) VOUT (2V/div) 0 0 VIN (2V/div) ON (2V/div) IOUT (4A/div) 0 0 0 Time (10s/div) Time (2s/div) Thermal Shutdown Response Fault Delay from Short Circuit (RL = 1; CL = 0.47F) VOUT (5V/div) 0 VOUT (2V/div) IOUT (1A/div) 0 IOUT (1A/div) FLT (5V/div) 0 Time (50ms/div) 6 0 0 Time (1ms/div) www.analogictech.com 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Functional Block Diagram Reverse Blocking OUT IN Over-Temp. Protection UnderVoltage Lockout FLT 4ms Delay ON/ON 1.2V Reference Current Limit Control SET GND Functional Description The AAT4614 is a single channel current limiting load switch that is intended to protect against short circuit and over current events by current limiting to a preset level. This device also provides a reverse current blocking feature, on / off enable control, and a fault flag to notify a system controller of an over current, short circuit or over temperature event. In the event of a load current exceeding a user programmed current limit level (ILIM), a high speed current limit loop limits the current in a microsecond and will reset to low impedance once the short-circuit condition is removed. The AAT4614 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. This device may operate in a thermal cycling state indefinitely or until the over-current condition is removed. 4614.2009.10.1.3 The AAT4614 operates with 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 AAT4614 MOSFET is protected from entering the saturated region of operation by being automatically shutting down via an under-voltage lockout circuit. Current limit or over temperature conditions are 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 AAT4614 is ideally suited for protection of peripheral ports such as USB, RS232, and parallel ports. Reverse Current Blocking The AAT4614's reverse current blocking feature prevents current to flow from OUT to IN when the device is disabled. When the device is enabled, the electrical characteristics between IN and OUT is still similar to an ideal switch; current can flow in either direction. www.analogictech.com 7 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Application Information So, RSET = Setting the Current Limit 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 and OUT, plus the operating temperature. Together, these three factors add up to a 25% tolerance (see ILIM specification in "Electrical Characteristics" section). Figure 1 illustrates a cold device with a statistically higher current limit and a hot device with a statistically lower current limit, both with RSET equal to 10.5k. While the chart, "RSET vs. ILIM" indicates an ILIM of 0.7A with an RSET of 10.5k, this figure shows that the actual current limit will be at least 0.525A and no greater than 0.875A. Normalized Current Limit (A) 1.2 1 -40C 0.88A 0.8 0.6 RSET (k) ILIM Typ. (mA) RSETILMT Coefficient (kV) 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 8.04 7.73 7.47 7.74 7.84 8.01 8.10 8.09 7.80 7.35 7.10 6.75 6.81 6.64 6.59 6.49 6.50 85C Table 1: Current Limit Standard RSET Values. 0.53A 0.4 0.2 Input Capacitor 0 0 1 2 3 4 5 VOUT (V) Figure 1: Current Limit at High and Low Temperature Using 10.5k To determine RSET, start with the application required current limit as the minimum current limit value and multiply it by 1.33 to derive the typical current limit value. Next, refer to Table 1 to find the approximate RSET value. For greater precision, use the small current limit range linear approximation to calculate RSET value. For example, for 500mA current limit requirement, first calculate the typical current limit: 500 * 1.33 = 665mA. Then refer to Table 1; the nearest small current limit range is 600mA to 700mA with 100mA current limit interval and 0.45kV RSETILIM coefficient interval. Then adopt the method of linear approximation in small range to calculate the RSETILIM coefficient. RSET * ILIM = 7.8 - 8 7.51kV = 11.3k 665mA 0.45 * (665 - 600) = 7.51kV 100 The input capacitor CIN protects the power supply from current transients generated by the load attached to the AAT4614. When a short circuit is suddenly applied to the output of the AAT4614, a large current, limited only by the RDS(ON) of the MOSFET, will flow for less than 1s before the current limit circuitry activates. (See the curve "Short Circuit Through 0.3" in the "Typical Characteristics" section of this datasheet.) 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 AAT4614. The extremely fast short-circuit response time of the AAT4614 reduces the size requirement for 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. www.analogictech.com 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Output Capacitor Thermal Considerations In order to insure stability while current limit is active, a low capacitance (approximately 0.47F) is required. No matter how large the output capacitor, output current is limited to the value set by the AAT4614 current limiting circuitry, so very large output capacitors can be used. Since the AAT4614 has internal current limit and overtemperature 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. For example, USB ports are specified to have at least 120F of capacitance downstream from their controlling power switch. The current limiting circuit will allow an output capacitance of 1000F or more without disturbing the upstream power supply. ON/ON(Enable Input) Eq. 1: TJ(MAX) = IMAX2OUT-SW(MAX) * RDS(ON)(MAX) * RJA + TA(MAX) In many systems, power planes are controlled by integrated circuits which run at lower voltages than the power planes themselves. The enable input (ON) of the AAT4614 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. Both active high and active low options are available for all packages. In Equation 1, IMAX is the maximum current required by the load. RDS(ON)(MAX) is the maximum rated RDS(ON) of the AAT4614 at high temperature. RJA is the thermal resistance between the AAT4614 die and the board onto which it is mounted. TA(MAX) is the maximum temperature that the PCB under the AAT4614 would be if the AAT4614 were not dissipating power. Equation 1 can be rearranged to solve for IMAX, as shown in Equation 2. Connecting to Capacitive Load When switching the AAT4614 onto a capacitive load, the AAT4614 will charge the output capacitive load at a rate no greater than the current limit setting. FAULT Output The FAULT Flag (FLT) is provided to alert the system if an AAT4614 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 an approximately 100 resistor. The filtering of voltage or current transients of less than 4ms prevents capacitive loads connected to the AAT4614 output from activating the FAULT Flag when they are initially attached. Pull-up resistances of 1k to 100k are recommended. Since FLT 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. The FLT Pin is not available for the SOT23-5 package. 4614.2009.10.1.3 Eq. 2: IMAX = TSD(MIN) - TA(MAX) RDS(ON)(MAX) * RJA TSD(MIN) is the minimum temperature required to activate the AAT4614's over-temperature protection. With the typical specification of 125C, 115C is a safe minimum value to use. For example, if an application is specified to operate in 50C environments, the PCB operates at temperatures as high as 85C. The application is sealed and its PCB is small, causing RJA to be approximately 150C/W. Using Equation 2, www.analogictech.com Eq. 3: IMAX = 115 - 85 = 0.93(A) 0.23 * 150 9 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Evaluation Board PCB Layout Figure 2: AAT4614 Evaluation Board Layout for SOT23-6 and SOT23-5 Package (Top View). Figure 3: AAT4614 Evaluation Board Layout for SOT23-6 and SOT23-5 Package (Bottom View). Figure 4: AAT4614 Evaluation Board Layout for SC70JW-8 Package (Top View). Figure 5: AAT4614 Evaluation Board Layout for SC70JW-8 Package (Bottom View). 10 www.analogictech.com 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Evaluation Board Schematic C2 0.47F TP1 U1 C1 1F AAT4614 1 OUT IN 6 OUT 2 GND SET 5 TP2 3 FLT ON/ON 4 TP 4 IN R1 6.8K TP5 TP6 SET ON GND R2 100K TP3 1 FAULT/SET 2 R3 6.8K 3 JP1 Note: Do Not Solder R3 for SOT23-6 Device; Do Not Solder R1,R2 for SOT23-5 Device Figure 6: AAT4614 Evaluation Board Schematic for SOT23-6 and SOT23-5 Package. R2 100K U1 AAT4614 TP2 TP3 TP6 ON FAULT 1 FLT GND 8 2 ON/ON GND 7 3 SET GND 6 4 IN OUT 5 TP5 SET TP4 R1 6.8K IN GND TP1 C1 1F C2 0.47F OUT JP1 1 2 3 Figure 7: AAT4614 Evaluation Board for SC70JW-8 Package. 4614.2009.10.1.3 www.analogictech.com 11 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Component Part Number Description Manufacturer C1 C2 JP1 R1 R2 R3 TP1 TP2 TP3 TP4 TP5 TP6 U1 GRM219R61A475KE19 GRM219R61A475KE19 CAP Ceramic 1F 10V X5R 10% 0603 CAP Ceramic 0.47F10V X5R 10% 0805 Device Enable/Disable Selector 6.8K, 1/16W 1% 0603 SMD 100K, 1/16W 1% 0603 SMD 6.8K, 1/16W 1% 0603 SMD, for SOT23-5 package device only OUT GND FAULT (SOT23-6) / SET (SOT23-5) IN SET (for SOT23-6 only) ON/ON Load Switch Murata Murata Chip Resistor Chip Resistor Chip Resistor 5010K-ND 5011K-ND 5010K-ND 5010K-ND 5010K-ND 5010K-ND AAT4614AI(GU/GV/JS)-(1/2)-T1 Vishay Vishay Vishay Keystone Keystone Keystone Keystone Keystone Keystone AnalogicTech Table 2: AAT4614 Evaluation Board Bill of Materials (BOM). 12 www.analogictech.com 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Ordering Information Enable Input Package Marking1 Part Number (Tape and Reel)2 Active High Active High Active Low Active Low Active Low Active High SOT23-6 SOT23-5 SOT23-6 SOT23-5 SC70JW-8 SC70JW-8 5BXYY 5CXYY 8YXYY AAT4614IGU-2-T1 AAT4614IGV-2-T1 AAT4614IGU-1-T1 AAT4614IGV-1-T1 AAT4614IJS-1-T1 AAT4614IJS-2-T1 5DXYY 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/aboutus/quality.php. Package Information SOT23-6 2.85 0.15 1.90 BSC 2.80 0.20 0.15 0.07 4 4 1.10 0.20 1.20 0.25 0.075 0.075 1.575 0.125 0.95 BSC 10 5 0.40 0.10 x 6 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. 4614.2009.10.1.3 www.analogictech.com 13 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag SOT23-5 2.85 0.15 1.90 BSC 10 5 0.40 0.10 0.075 0.075 0.15 0.07 4 4 1.10 0.20 0.60 REF 1.20 0.25 2.80 0.20 1.575 0.125 0.95 BSC GAUGE PLANE 0.45 0.15 0.60 REF 0.10 BSC 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. 14 www.analogictech.com 4614.2009.10.1.3 PRODUCT DATASHEET AAT4614 SmartSwitchTM Adjustable Current Limited Load Switch with Fault Flag Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 (c) 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. Except as provided in AnalogicTech's terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. 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. 4614.2009.10.1.3 www.analogictech.com 15