PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection General Description Features The AAT4686 OVPSwitch™ is a member of AnalogicTech’s Application Specific Power MOSFET™ (ASPM™) product family. It is a P-channel MOSFET driver IC with precise over-voltage protection control, designed to protect lowvoltage systems against high-voltage faults up to +28V. If the input voltage exceeds the programmed over-voltage threshold, the external P-channel MOSFET switch will be turned off to prevent damage to the output load circuits. The AAT4686 is available with an internally programmed over-voltage trip point or as an adjustable version programmed by a two external resistors. • Over-Voltage Protection up to 28V • (Fixed or Adjustable) Over-Voltage Protection Threshold • Fast OVP Response: ▪ 1 μs (Max) to Over-Voltage Transient • Low Operation Quiescent Current ▪ 30μA Typical ▪ 1μA Max in Shutdown (Disabled) • Drives External P-Channel MOSFETs • Under-Voltage Lockout • Temperature Range: -40 to 85°C • Available in SC70JW-8 Package The AAT4686 also includes an under-voltage lockout (UVLO) protection circuit, which will put the device into sleep mode at low input voltages only consuming < 1μA of current. The AAT4686 is offered in a small Pb-free, 8-pin SC70JW package, and is specified for operation over the -40°C to +85°C ambient temperature range. Applications • • • • • • Cell Phones Digital Still Cameras GPS MP3 Players Personal Data Assistants (PDA) USB Hot Swap / Live Insertion Devices Typical Application Adjustable Version Fixed Version* VOUT VOUT +5V +5V VIN 3.75V – 28V IN VIN 3.75V – 28V GATE IN GATE OVP 1μF EN GND FLT Fault Flag 1μF EN GND FLT Fault Flag * Contact manufacturer for available options. 4686.2008.02.1.0 www.analogictech.com 1 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Pin Descriptions Pin # Fixed Symbol Adj. 1 2 3 N/C Function IN GATE GND 4 Power input pin. Connect a 1μF capacitor from IN to GND. Gate connection to external P-channel MOSFET. Ground. Fixed version: not connected. Adjustable version: Over-voltage protection threshold input. Over-voltage fault reporting. Enable input, active low. When connected high, the device shuts down and draws less than 1.0μA of current. An internal pull-down resistor is connected to this pin. NC/OVP 5 FLT 6, 7, 8 EN Pin Configuration Fixed OVP Trip Voltage Version SC70JW-8 (Top View) 2 Adjustable OVP Trip Voltage Version SC70JW-8 (Top View) IN 1 8 EN IN 1 8 EN GATE 2 7 EN GATE 2 7 EN GND 3 6 EN GND 3 6 EN N/C 4 5 FLT OVP 4 5 FLT www.analogictech.com 4686.2008.02.1.0 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Absolute Maximum Ratings1 Symbol VIN VOVP VFLT, VEN VGATE TJ Description IN to GND OVP to GND FLT, EN to GND GATE to GND Operating Junction Temperature Range Value Units -0.3 to 28 -0.3 to 6.5 -0.3 to 6.5 28 -40 to 150 V V V V °C Value Units 225 440 °C/W mW Thermal Characteristics Symbol θJA PD Description Maximum Thermal Resistance2 Maximum Power Dissipation2, 3 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 a FR4 board. 3. Derated 4.4mW/°C above 25°C 4686.2008.02.1.0 www.analogictech.com 3 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Electrical Characteristics1 VIN = 5V, TA = -40° to 85°C unless otherwise noted. Typical values are at TA = 25°C. Symbol VIN IQ Description Conditions Normal Operation Voltage Range Operation Quiescent Current Shutdown Supply Current Under-Voltage Lockout Threshold Under-Voltage Lockout Hysteresis VIN = 5V, EN = 0V, IOUT = 0 EN = IN, VIN = 5.5V, VOUT = 0 Rising Edge IG Logic VEN(L) VEN(H) IEN FLTOL FLTIOL TBLK_FLT TD_FLT TRESP_OV TON TR TOFF Rising Edge 30 3 0.1 1.083 Rising Edge EN = VIN Units 14 50 1 3.3 V μA μA V V 1.117 V mV V mV VIN V VIN 5V 1 Gate Current EN Input Low Voltage EN Input High Voltage EN Input Leakage FLT Output Voltage Low FLT Output Leakage Current FLT Blanking Time FLT Assertion Delay Time from Over-Voltage (OV) Gate Turn On Delay Time Gate Turn On Fall Time Gate Turn Off Delay Time 1.1 20 Max 6.5 120 Gate Voltage Low Level2 Over-Voltage Response Time Typ 3 ISD(OFF) VUVLO VUVLO_HYS Adjustable Over-Voltage Lockout Threshold, OVP Pin VOVP_TH VOVP_HYS Over-Voltage Lockout Threshold Hysteresis, OVP Fixed VOVPT Over-Voltage Protection Trip Voltage VOVP_HYS Over-Voltage Protection Trip Point Hysteresis, IN Pin Gate Output VGHL Gate Voltage High Level VGLL Min V μA 0.4 1.6 VEN = 5.5V or 0V IFLT = 1mA From De-assertion of OV From Assertion of OV VIN = 5V, VOVP Rise to 1.13V from 1.07V in 1ns VIN = 5V; CG = 400pF VIN = 5V; CG = 400pF VIN = 5V; CG= 400pF 0.5 5 10 1 2.0 0.4 1 15 V V μA V μA ms μs 0.7 μs 10 4 6 ms ms ms 1. The AAT4686 is guaranteed to meet performance specification over the -40 to 85°C operating temperature range and are assured by design, characterization and correlation with statistical process controls. 2. VGS (i.e. VIN_GATE) is clamped to typical 5V. 4 www.analogictech.com 4686.2008.02.1.0 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Typical Characteristics Operation Quiescent Current vs. Supply Voltage Operation Quiescent Current vs. Temperature 40 45 Quiescent Current (µA) Quiescent Current (µA) 50 40 35 30 25 20 15 10 5 0 35 30 25 20 15 3 4 5 6 7 8 9 10 11 12 13 -40 14 -15 Supply Voltage (V) 1.8 1.2 0.6 0.0 8 10 12 14 16 18 20 22 24 26 28 Shutdown Supply Current (µA) Shutdown Supply Current (µA) 2.4 6 60 85 Shutdown Supply Current vs. Temperature 3.0 4 35 Temperature (°C) Shutdown Supply Current vs. Supply Voltage 2 10 0.35 0.28 0.21 0.14 0.07 0.00 -40 Supply Voltage (V) -15 10 35 60 85 Temperature (°C) FLT Blanking Time vs. Temperature FLT Blanking Time (VIN = 5.0V) FLT Blanking Time (ms) 12 VOUT (1V/div) 11 5.0V 4.3V 10 FLT (2V/div) 9 8 OVP (100mV/div) 7 -40 -15 10 35 60 1.15V 85 Temperature (°C) 4686.2008.02.1.0 0V Time (2ms/div) www.analogictech.com 5 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Typical Characteristics UVLO Threshold (V) 4.00 3.50 VIN Rising 3.00 VIN Falling 2.50 2.00 1.50 -40 -15 10 35 60 85 Over-Voltage Response Time vs. Temperature Over-Voltage Response Time (ns) Undervoltage Lockout Threshold vs. Temperature 800 750 700 650 600 550 -40 -15 10 Temperature (°C) 85 EN Input High Voltage vs. Supply Voltage 1.1 1.12 1.11 VEN(H) (V) 1.09 VOVP_HYS 1.08 -40°C 1.0 VOVP_TH 1.10 VOVP 60 Temperature (°C) Over-Voltage Lockout Threshold (Adjustable Version) vs. Temperature 0.9 25°C 0.8 85°C 0.7 1.07 1.06 -40 0.6 -15 10 35 60 3 85 4 5 6 7 Temperature (°C) 8 9 10 11 12 13 14 Supply Voltage (V) EN Input Low Voltage vs. Supply Voltage 1.1 Turn Off Delay Time (VIN = 5.0V, RO = 10Ω Ω) -40°C 1.0 VEN(L) (V) 35 0.9 4.84V VOUT (2V/div) 25°C 0.8 85°C 0.7 EN (2V/div) 0V 0.6 3 4 5 6 7 8 9 10 11 12 13 14 Supply Voltage (V) 6 Time (2ms/div) www.analogictech.com 4686.2008.02.1.0 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Typical Characteristics Turn On Delay Time (VIN = 5.0V, RO = 10Ω Ω) VOUT (2V/div) 0V EN (2V/div) 0V Time (2ms/div) 4686.2008.02.1.0 www.analogictech.com 7 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Functional Block Diagram Fixed Option IN GATE OVP Sense and Control OVP GND EN Functional Description In conjunction with an external P-channel power MOSFET, the AAT4686 provides up to 28V over-voltage protection when powering low-voltage systems such as cell phones, MP3, and PDAs or when charging Lithium-Ion batteries from a poorly regulated supply. The P-channel MOSFET is inserted between the power supply or charger source and the load to be protected. The AAT4686 IC consists of a P-channel MOSFET slew-rate controlled driver, under-voltage lockout protection, over-voltage monitor, fast shutdown circuitry, and a fault output flag. In normal operation, the P-channel MOSFET is controlled by the AAT4686, connecting and disconnecting the power supply from IN to OUT. A low resistance MOSFET is used to minimize the voltage drop between the voltage source and the load and to reduce the power dissipation. Any P-channel MOSFET can be used; however, the turn-on and turn-off speed will vary inversely pro- 8 FLT portionately to the MOSFET ON-resistance. When the input voltage exceeds the programmed voltage limit (internally set or externally by a voltage divider to the OVP pin), the device immediately turns off the external P-channel FET, disconnecting the load from the abnormal voltage and thus preventing damage to any downstream components. Simultaneously, the fault flag is raised, alerting the system to a problem. If an over-voltage condition is applied at the time of the device enable, then the switch will remain OFF. The AAT4686 can also be used as a simple slew-rate controlled P-channel high side driver IC. Under-Voltage Lockout (UVLO) The AAT4686 has a fixed 3.0V under-voltage lockout level (UVLO). When the input voltage is less than the UVLO level, the MOSFET is turned off. 100mV of hysteresis is included to ensure circuit stability. www.analogictech.com 4686.2008.02.1.0 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Application Information Over-Voltage Protection The AAT4686 adjustable version has a 1.1V ± 1.5% overvoltage trip threshold on the OVP pin. With a resistor divider on OVP pin from IN to GND, the over-voltage trip point can be adjusted anywhere within the input voltage range (see Table 1). Once the over-voltage trip level is triggered, the external PMOS switch controller will shut off the PMOS in less than 1μs. The AAT4686 fixed version is also available with the resistor divider internally integrated and the input voltage trip point at 6.5V. The fixed version of the AAT4686 does not have a connection to the internal OVP circuitry and Pin 4 is designed to be not connected. FLT Output The FLT output is an active-low open-drain fault (OV) reporting output. A pull-up resistor should be connected from FLT to the logic I/O voltage of the host system. FLT will be asserted immediately if an over-voltage fault occurs (only about a 1μs inherited internal circuit delay). A 10ms blanking is applied to FLT signal prior to deassertion. EN Input EN is an active-low enable input. EN is driven low, connected to ground, or left floating for normal device operation. Taking the EN high turns off the MOSFET. In the case of an over-voltage or UVLO condition toggling the EN will not override the fault condition and the switch will remain off. The AAT4686 over-voltage protection circuit provides fast protection against transient voltage spikes and short duration spikes of high voltage from the power supply lines. The AAT4686 can quickly disconnect the input supply from the load and not cause any damage to sensitive components. In portable product applications, if the user removes the battery pack during charging, this action can create large transients and a high voltage spike can occur which can damage other electronic devices in the product such as the battery charger. A hot plug of the AC/DC wall adapter into the AC outlet can create and release a voltage spike from the transformer. As a result, some sensitive devices within the product can be damaged. With the AAT4686 placed between the power lines and the sensitive devices, the voltage spike can be kept away and the input supply disconnected from other devices in 0.7μs. Figure 2 shows the response time of over-voltage protection from the test circuit (Figure 1). The input voltage is rapidly increased from 5V to 12V by a voltage surge or voltage spike. The voltage at the OVP pin is also increased until the trip point is triggered. At this point, the FLT pin is pulled low and the output voltage starts to fall. Figure 3 shows a zoom-in scope capture of the OVP response time; the output is disconnected from the input in as little as 700ns. Adjustable Version Over-Voltage Protection Resistors Device Operation On initial power-up, if VIN < UVLO or if VOVP > VOVP_TH (1.1V), the PMOS is held off. If UVLO < VIN, VOVP < VOVP_TH, and EN is low, the device enters startup after a 10ms internal delay. 4686.2008.02.1.0 Over-Voltage Protection The over-voltage protection threshold is programmed with two resistors, R1 and R2. To limit the current going through the external resistor string while maintaining good noise immunity, use smaller resistor values, such as 10KΩ for R2. Using a larger value will further reduce the system current, but will also increase the impedance of the OVP node, making it more sensitive to external noise and interference. A suggested value for R2 is 110KΩ. Table 1 summarizes resistor values for various over-voltage settings. Use 1% tolerance metal film resistors for programming the desired OVP setting. www.analogictech.com 9 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection R2 (KΩ) R1 (KΩ) VOVP Setting (V) 110 110 110 110 110 110 110 110 110 110 487 536 787 1050 1300 1540 1780 2050 2320 2550 6.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 26.5 Table 1: Recommended OVP Setting for AAT4686 Adjustable Version1. SCOPE +12V LOAD AAT4686 10Ω Vin 1 2 3 4 8 7 6 5 gnd Vout GND +5V OVP Fault Figure 1: Over-Voltage Protection Response Time Test Circuit. VIN (5V/div) OVP (50mV/div) 12V OVP (200mV/div) Output Load = 10Ω COUT = 1µF OVP Trip Point (1.1V) 0.7µs VOUT (100mV/div) VOUT (5V/div) 1.23V 1.03V Output Load = 10Ω No COUT 5V FLT (2V/div) FLT (2V/div) Time (200µs/div) Time (500ns/div) Figure 2: Typical Over-Voltage Response Time. Figure 3: Typical Over-Voltage Response Time [zoom in]. 1. Mimimum OVP voltage setting = 5V. 10 www.analogictech.com 4686.2008.02.1.0 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Input Capacitor A 1μF or larger capacitor is typically recommended for CIN. 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. Capacitors are typically manufactured in different voltage ratings. 16V, 25V, and 50V are good for OVP applications. If the maximum possible surge voltage is known, select capacitors with a voltage rating at least 5V higher than the maximum possible surge voltage. Otherwise, 50V rated capacitors are generally good for most OVP applications to prevent any surge voltage. Output Capacitor In order to insure stability while current limit is active, a small output capacitance of approximately 1μF is required at the output. Likewise, with the output capacitor, there is no specific capacitor ESR requirement. If desired, COUT may be increased to accommodate any load transient condition. must be taken into account. The following discussions will assume the load switch is mounted on a printed circuit board utilizing the minimum recommended footprint as stated in the “Printed Circuit Board Layout Recommendations” section of this datasheet. At any given ambient temperature (TA), the maximum package power dissipation can be determined by the following equation: PD(MAX) = Constants for the AAT4686 are maximum junction temperature (TJ(MAX) = 125°C) and package thermal resistance (θJA = 225°C/W). Worst-case conditions are calculated at the maximum operating temperature, TA = 85°C. Typical conditions are calculated under normal ambient conditions where TA = 25°C. At TA = 85°C, PD(MAX) = 175mW. At TA = 25°C, PD(MAX) = 440mW. The maximum continuous output current for the AAT4686 is a function of the package power dissipation and the RDS of the MOSFET at TJ(MAX). The maximum RDS of the MOSFET at TJ(MAX) is calculated by increasing the maximum room temperature. For maximum current, refer to the following equation: IOUT(MAX) = FAULT Flag A FAULT flag is provided to alert the system if the AAT4686’s input voltage has passed the pre-programmed over-voltage trip point. Since the FAULT is open drain pin, it should be pulled up to input/output voltage rail and less than the maximum operating voltage of 6.5V. Thermal Considerations and High Output Current Applications The AAT4686 is designed to deliver a continuous output load current. The limiting characteristic for maximum safe operating output load current is package power dissipation. In order to obtain high operating currents, careful device layout and circuit operating conditions 4686.2008.02.1.0 TJ(MAX) -TA θJA PD(MAX) RDS Printed Circuit Board Layout Recommendations For proper thermal management, certain circuit board layout rules should be followed: VIN and VOUT should be routed using wider than normal traces, and GND should be connected to a ground plane. To maximize package thermal dissipation and power handling capacity of the AAT4686 SC70JW-8 package, the ground plane area connected to the ground pins should be made as large as possible. For best performance, CIN and COUT should be placed close to the package pins; see Figures 4 and 5. www.analogictech.com 11 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Figure 4: AAT4686 Evaluation Board Component Side Layout. VIN Figure 5: AAT4686 Evaluation Board Solder Side Layout. VOUT U2 SC70JW-8 1 2 3 4 S S S G D D D D 8 7 6 5 +5V AAT8303 Enable JP1 U1 SC70JW-8 1 2 3 4 R1 C1 1μF VIN EN GATE EN GND EN OVP FLT AAT4686 8 7 6 5 DS1 Red LED R3 1.5K C2 1μF R2 110k R1 (kΩ) VOVP_SETTING (V) 487 536 787 1050 1300 6.0 6.5 9.0 11.5 14.0 Input Cap, C1 C1 1206 X7R 1μF 50V GRM31MR71H105KA88 (C1 1206 X7R 2.2μF 50V GRM31CR71H225KA88L) (C1 1210 X7R 4.7μF 50V GRM32ER71H475KA88L) Output Cap, C2 for under 13V application, C2 0805 X7R 1μF 16V GRM21BR71C105KA01 (for under 20V application, C2 0805 X7R 1μF 25V GRM219R71E105KA88) Figure 6: AAT4686 Evaluation Board Schematic. 12 www.analogictech.com 4686.2008.02.1.0 PRODUCT DATASHEET AAT4686 OVPSwitchTM MOSFET Driver IC with Over-Voltage Protection Ordering Information Package OVP Trip Voltage Marking1 Part Number (Tape and Reel)2 SC70JW-8 SC70JW-8 Adjustable 6.5V YAXYY AAT4686IJS-T1 AAT4686IJS-6.5-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/about/quality.aspx. Package Information 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 measurements in millimeters. 1. XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 © 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. 4686.2008.02.1.0 www.analogictech.com 13