AAT4670 Dual-Input, Dual-Output Load Switch General Description Features The AAT4670 SmartSwitch is a member of AnalogicTech’s Application Specific Power MOSFET™ (ASPM™) product family. The AAT4670 consists of dual, independent, 1A current limited, slew rate controlled P-channel MOSFET power switches with a dedicated source and drain pin assigned to each switch. The internal circuitry automatically derives power from the higher of the two input power source pins with a low operating quiescent current of 18µA. In shutdown mode, the supply current decreases to less than 1µA. The switches operate with inputs ranging from 2.2V to 5.5V, making them ideal for 2.5V, 3V, and 5V systems. The dual configuration permits integration of the load switch function for systems with two different power busses. Independent under-voltage lockout circuits will shut down the corresponding switch if its input voltage falls below the under-voltage lockout threshold. If the die temperature reaches the thermal limit, both switches thermal cycle off and on indefinitely without damage until the thermal condition is removed. An open drain FAULT output signals an over-current or over-temperature condition for each channel. Input logic levels are TTL compatible. • • • • • • • • • • • • SmartSwitch™ 2.2V to 5.5V Input Voltage Range 1A Current Limit Per Channel 95mΩ Typical RDS(ON) Fast Transient Response: — <1µs Response to Short Circuit Low 18µA Quiescent Current 1µA Max with Switches Off Slew Rate Controlled Thermal Shutdown Fault Flags with 3ms Blanking Under-Voltage Lockout Temperature Range: -40°C to +85ºC Available in TDFN33-12, SOP-8, TSSOP-8, or MSOP-8 Package Applications • • • • • • The AAT4670 is available in a Pb-free, space-saving, thermally-enhanced TDFN 3x3x0.8mm 12-lead package. The device is also available in a Pb-free 8-pin SOP, TSSOP, or MSOP package and is specified over the -40°C to +85°C temperature range. Hot Swap Supplies Media Bay Notebook Computer PDA, Subnotebook Peripheral Ports USB Ports Typical Application AAT4670 INA INB EN INA INB EN GND CINA 1μF GND 4670.2006.09.1.4 CINB 1μF OUTA OUTB FAULTA FAULTB OUTA OUTB FAULTA FAULTB COUTA 1μF COUTB 1μF GND 1 AAT4670 Dual-Input, Dual-Output Load Switch Pin Descriptions Pin # TDFN Other Pkgs Symbol Function 1, 12 8 OUTA 2 1 EN 3 2 FAULTA Open drain output; signals over-current for OUTA and over-temperature condition. 4 3 FAULTB Open drain output; signals over-current for OUTB and over-temperature condition. 5 4 GND Ground connection. 6, 7 5 OUTB P-channel MOSFET drain channel B. 8, 9 6 INB P-channel MOSFET source channel B. 10, 11 7 INA P-channel MOSFET source channel A. P-channel MOSFET drain channel A. Active-low enable input (logic low turns the switches on). EP Exposed paddle (bottom); connect to ground as closely as possible to the device. Pin Configuration TDFN33-12 3 10 4 9 5 8 6 7 OUTA INA INA INB INB OUTB 8 OUTA 7 INA 3 6 INB 4 5 OUTB 8 OUTA 2 11 1 12 2 2 1 1 OUTA EN FAULTA FAULTB GND OUTB SOP-8 7 INA EN 1 FAULTA 2 FAULTB GND TSSOP-8 2 MSOP-8 EN 1 INA FAULTA 2 6 INB FAULTB 3 6 INB 5 OUTB GND 4 5 OUTB EN 1 8 OUTA FAULTA 2 7 FAULTB 3 GND 4 4670.2006.09.1.4 AAT4670 Dual-Input, Dual-Output Load Switch Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol Description VINA,B VOUTA,B VFAULTA,B IOUT TJ VESD TLEAD INA or INB to GND OUTA or OUTB to GND FAULTA or FAULTB 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 6 -0.3 to 6 Internally Limited -40 to 150 4000 300 V V V A °C V °C Value Units Thermal Characteristics3 Symbol Description ΘJA Maximum Thermal Resistance PD Maximum Power Dissipation SOP-8 TDFN33-12 SOP-8 TDFN33-12 100 50 1.25 2.0 °C/W W 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. 4670.2006.09.1.4 3 AAT4670 Dual-Input, Dual-Output Load Switch Electrical Characteristics VIN = 5V, TA = 25°C, unless otherwise noted. Bold values designate -40°C to +85°C temperature range. Symbol Description VIN IQ ILIM t1 t2 t3 t4 VEN(L) Operation Voltage Quiescent Current Off Supply Current Off Switch Current Under-Voltage Lockout On-Resistance Channel A or B Switch Resistance Temperature Coefficient Current Limit Channel A or B Output Turn-On Delay Time Output Rise Time Output Turn-Off Delay Time Output Fall Time EN Input Low Voltage VEN(H) EN Input High Voltage IQ(OFF) ISD(OFF) VUVLO RDS(ON) TCRDS IEN(SINK) tRESP VFAULTLOW ISINK Tblank TSD EN Input Leakage Current Loop Response FAULT Logic Output Low FAULT Logic Output High Leakage Current Fault Blanking Time Over-Temperature Threshold Conditions Min Typ 2.2 VINA or VINB = 5V IOUTA = IOUTB = 0 EN = VIN, VINA = VINB = 5V, OUTA, OUTB Open EN = VIN, VINA = VINB = 5V, VOUTA = VOUTB = 0V 18 0.1 1.7 95 105 VIN = 5.0V VIN = 3.0V Max Units 5.5 40 1 1 2.2 130 150 2800 VOUT < VIN to 0.5V VIN = 5V, OUT = 0 to 10%, RLOAD = 20Ω VIN = 5V, OUT = 10% to 90%, RLOAD = 20Ω VIN = 5V, OUT = 100% to 90%, RLOAD = 20Ω VIN = 5V, OUT = 90% to 10%, RLOAD = 20Ω VIN = 2.7V to 5.5V1 VIN = 2.7V to < 3.6V VIN = 3.6V to 5.5V VEN = 5.5V VIN = 5V ISINK = 1mA VFAULT = 5.5V 1.0 1.25 100 100 10 5 V µA µA µA V mΩ ppm/°C 1.50 1000 1000 20 20 0.8 2.0 2.4 A µs µs µs µs V V 0.01 750 0.5 3 125 1 0.4 1 µA ns V µA ms °C 1. For VIN outside this range, consult typical EN threshold curve. 4 4670.2006.09.1.4 AAT4670 Dual-Input, Dual-Output Load Switch Typical Characteristics Quiescent Current vs. Temperature Quiescent Current vs. Input Voltage 20 18 25 Input Current (μA) Quiescent Current (μA) 30 20 15 10 5 0 16 14 12 10 8 6 4 2 0 -40 -20 0 20 40 60 80 100 120 0 1 2 Off-Supply Current vs. Temperature 5 6 1.0000 Off-Switch Current (μA) Off-Supply Current (μA) 4 Off-Switch Current vs. Temperature 1.0000 0.1000 0.0100 0.0010 0.0001 0.0000 -40 -20 0 20 40 60 80 100 0.1000 0.0100 0.0010 0.0001 0.0000 120 -40 -20 0 Temperature (°C) 20 40 60 80 100 120 Temperature (°C) Current Limit vs. Output Voltage RDS(ON) vs. Temperature 1.4 150 1.2 140 1.0 RDS(ON) (mΩ) Output Current (A) 3 Input Voltage (V) Temperature (°C) 0.8 0.6 0.4 130 VIN = 3V 120 110 100 90 VIN = 5V 80 0.2 70 0.0 60 0 1 2 3 Output Voltage (V) 4670.2006.09.1.4 4 5 -40 -20 0 20 40 60 80 100 120 Temperature (°C) 5 AAT4670 Dual-Input, Dual-Output Load Switch Typical Characteristics FAULT Delay Start Into 0.6Ω Load Turn-On/Off Response with 20Ω 1µF Loads EN (5V/div) FAULT (5V/div) ON (5V/div) OUTB (5V/div) INB = 5V FAULT (5V/div) OUTA (5V/div) INA = 3V VOUT (1V/div) IINA + IINB (200mA/div) IIN (500mA/div) Time (100µs/div) Time (500µs/div) Short Circuit Through 0.3Ω 9 4 6 3 Output Current 2 0 Output Voltage 0 -3 -1 0 1 2 3 4 8 12 Input Voltage 6 4 4 Output Current 2 0 0 Output Voltage -2 -4 -1 Time (μs) 8 Output Current (A) Input Voltage 6 Input and Output Voltage (V) 8 Output Current (A) Input and Output Voltage (V) Short Circuit Through 0.6Ω 0 1 2 3 4 Time (μs) Typical EN Threshold vs. Input Voltage Thermal Shutdown Response ON (5V/div) FAULT (5V/div) VOUT (1V/div) IIN (500mA/div) EN Threshold (V) 2.4 2.2 2 1.8 VEN(H) 1.6 1.4 1.2 VEN(L) 1 0.8 0.6 1.5 Time (200ms/div) 6 2 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) 4670.2006.09.1.4 AAT4670 Dual-Input, Dual-Output Load Switch Functional Block Diagram INA OUTA ILIM Slew Rate UVLO EN OTMP UVLO ILIM Slew Rate INB OUTB FAULTA FAULTB GND Functional Description The AAT4670 dual channel load switch, implemented with isolated independent P-channel MOSFET devices, is ideal for applications where dual power supplies are in continuous use. Typical applications for this include products with multiple USB ports, or ports requiring protection that operate from separate power supplies. The input power supplies can be any voltage between 2.2V and 5.5V in any combination; one supply is not required to be the higher voltage. Internally, the power supply for the control circuitry will automatically switch to the higher of the two supplies. In the case where the supplies are equal, ±30mV of hysteresis prevents the internal supply from oscillating between the two input supplies. The low impedance P-channel MOSFET devices are identical in size, allowing for layout flexibility. They are controlled by a patented fast acting current loop and respond to short circuits in a fraction of a microsecond, easing requirements on the input capacitors. With such fast transient response time, the upstream power supply rail is naturally isolated from the protected port. a high ambient temperature or an over-current condition causes the die temperature to reach the internal thermal limit, both power devices are 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 or high temperature condition is removed. Due to the high thermal conductivity of silicon and the size of the die, the temperature across the die is relatively uniform at high temperatures; therefore, as a precaution, both power devices are switched off when the thermal threshold is reached. Since the power devices operate from independent power supplies, independent undervoltage lockout circuits are employed. If the power supply to one channel falls below the under-voltage lockout threshold, the other channel will remain active. A current limit condition is reported by the open drain FAULT output associated with the appropriate channel. A thermal limit condition is reported by both FAULT outputs. A three millisecond 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 AAT4670 is internally protected from thermal damage by an over-temperature detection circuit. If The AAT4670 is ideally suited for protection of peripheral ports such as USB, PS2, and parallel ports. 4670.2006.09.1.4 7 AAT4670 Dual-Input, Dual-Output Load Switch Applications Information Input Capacitor The input capacitors, CINA and CINB, protect the input power supplies from current transients generated by loads attached to the AAT4670. If a short circuit is suddenly applied to an output of the AAT4670, there is a 750 nanosecond period during which a large current flows before current limit circuitry activates. (See characteristic curve "Short Circuit Through 0.3Ω.") In this event, a properly sized input capacitor can dramatically reduce the voltage transient seen by the power supply and other circuitry upstream from the AAT4670. CIN should be located as close to the device VIN pin as practically possible. Ceramic, tantalum, or aluminum electrolytic capacitors may be selected for CIN. There is no specific capacitor equivalent series resistance (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. than approximately three milliseconds, the associated FAULT flag is pulled to ground through approximately 100Ω. Removal of voltage or current transients of less than three milliseconds prevents capacitive loads connected to either AAT4670 output from activating the associated 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 AAT4670 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. Output Capacitor In order to insure stability while the current limit is active, a small capacitance of approximately 1µF is required on each output. No matter how big the output capacitor, output current is limited to the value set by the AAT4670 current limiting circuitry, allowing very large output capacitors to 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. Attaching Loads Capacitive loads attached to the AAT4670 will charge at a rate no greater than the current limit setting. 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 AAT4670 at high temperature. RθJA is the thermal resistance between the AAT4670 die and the board onto which it is mounted. TA(MAX) is the maximum temperature that the PCB under the AAT4670 would be if the AAT4670 were not dissipating power. Equation 1 can be rearranged to solve for IMAX; Equation 2. Eq. 2: IMAX = TSD(MIN) - TA(MAX) RDS(ON)(MAX) · RΘJA FAULT Output FAULT flags are provided to alert the system if an AAT4670 load is not receiving sufficient voltage to operate properly. If current limit or over-temperature circuits in any combination are active for more 8 TSD(MIN) is the minimum temperature required to activate the AAT4670 over-temperature protection. With typical specification of 125°C, 115°C is a safe minimum value to use. 4670.2006.09.1.4 AAT4670 Dual-Input, Dual-Output Load Switch 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 120°C/W. Using Equation 2: Eq. 3: IMAX = To prevent thermal limiting, the operating load current in the application must be less than 1.25A which lies in the current limiting range. So, in this application, any operating current below the current limit threshold is allowed. 115 - 85 = 1.25A 160m · 120 Timing Diagram EN OUT t1 4670.2006.09.1.4 t2 t3 t4 9 AAT4670 Dual-Input, Dual-Output Load Switch Ordering Information Package Marking1 Part Number (Tape and Reel)2 SOP-8 4670 AAT4670IAS-T1 TSSOP-8 4670 AAT4670IHS-T1 MSOP-8 BFXYY AAT4670IKS-T1 TDFN33-12 AAT4670IWP-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 3.90 ± 0.10 6.00 ± 0.20 SOP-8 4.90 ± 0.10 1.27 BSC 45° 4° ± 4° 1.55 ± 0.20 0.42 ± 0.09 × 8 0.175 ± 0.075 0.375 ± 0.125 0.235 ± 0.045 0.825 ± 0.445 All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 10 4670.2006.09.1.4 AAT4670 Dual-Input, Dual-Output Load Switch 6.40 ± 0.20 4.40 ± 0.10 TSSOP-8 12° REF × 4 3.00 ± 0.10 1.05 MAX 0.245 ± 0.055 × 8 1.20 MAX 0.65 BSC 0.145 ± 0.055 4° ± 4° 0.60 ± 0.15 0.10 ± 0.05 DETAIL A 12° 1.00 REF All dimensions in millimeters. 4670.2006.09.1.4 11 AAT4670 Dual-Input, Dual-Output Load Switch MSOP-8 4° ± 4° 4.90 ± 0.10 3.00 ± 0.10 1.95 BSC 0.95 REF 0.60 ± 0.20 PIN 1 3.00 ± 0.10 0.85 ± 0.10 0.95 ± 0.15 10° ± 5° GAUGE PLANE 0.254 BSC 0.155 ± 0.075 0.075 ± 0.075 0.65 BSC 0.30 ± 0.08 All dimensions in millimeters. 12 4670.2006.09.1.4 AAT4670 Dual-Input, Dual-Output Load Switch TDFN33-12 2.40 ± 0.05 Detail "B" 3.00 ± 0.05 Index Area (D/2 x E/2) 0.3 ± 0.10 0.16 0.375 ± 0.125 0.075 ± 0.075 3.00 ± 0.05 1.70 ± 0.05 Top View Bottom View Pin 1 Indicator (optional) 0.23 ± 0.05 Detail "A" 0.45 ± 0.05 0.1 REF 0.05 ± 0.05 0.229 ± 0.051 + 0.05 0.8 -0.20 7.5° ± 7.5° Option A: C0.30 (4x) max Chamfered corner Side View Option B: R0.30 (4x) max Round corner Detail "B" Detail "A" 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 4670.2006.09.1.4 13