Evaluates: MAX6495 19-4002 Rev 2 12/06 MAX6495 Evaluation Kit General Description Features The MAX6495 evaluation kit (EV kit) demonstrates a 5.5V to 72V Wide Supply Voltage Range high-voltage overvoltage protection circuit for automo- Up to 5A Output Current Capacity tive applications that must survive load dump and high- voltage transient conditions. This EV kit is a fully assem- Selectable Overvoltage Mode and Overvoltage bled and tested surface-mount board. Limiter Mode This EV kit supports high output currents of up to 5A, Adjustable Overvoltage Threshold operates at voltages up to 72V, and withstands temper- atures ranging from -40C to +105C. Two alternate 100V Reverse-Battery Protection voltage inputs implement two different schemes for reverse-battery protection. Ordering Information PART TEMP RANGE IC PACKAGE MAX6495EVKIT -40C to +105C 6 TDFN-EP* *EP = Exposed paddle. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION J1 0 Not installed, 2-pin header 22F, 100V aluminum electrolytic C1, C7 2 capacitors J2, J3, J4 3 3-pin headers Vishay 222215369229 100V, 33A n-channel MOSFET C2, C8C12 0 Not installed, capacitors M1 1 International Rectifier IRF540NS or Fairchild FQB33N10 C3 1 Not installed, capacitor (1206) 100V, 23A p-channel MOSFET 0.1F, 100V X7R ceramic capacitor M2 1 International Rectifier IRF9540NS or TDK C3216X7R2A104K or C6 1 Fairchild FQB22P10 AVX 12061C104KAT2A R1 1 649k 1% resistor (0805) C13 1 Not installed, electrolytic capacitor R2 1 49.9k 1% resistor (0805) 8A/100V Schottky diode R4 1 Not installed, resistor (0805) D1 1 International Rectifier 8TQ100S or R5 1 100k 1% resistor (0805) ST Microelectronics STPS8H100G R6 1 2.2M 1% resistor 60V, 600W TVS diode U1 1 MAX6495ATT (6-pin TDFN) D2 1 Diodes SMBJ54A or Fairchild SMBJ54A 1 PCB: MAX6495EVKIT 18V zener diode Central Semi CMPZ5248B or D3 1 Diodes MMBZ5248BT Not installed, optional TVS diode D4 1 (DO-15) Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX6495 Evaluation Kit have diode-based and p-channel MOSFET-based Quick Start reverse-battery protections, respectively, and VIN1 The MAX6495 EV kit is fully assembled and tested. bypasses all reverse-battery protections. Follow these steps to verify operation. Caution: Do not turn on the power supply until all connections are Overvoltage Mode completed. In overvoltage mode, the MAX6495 monitors the input voltage and turns off the series-pass n-channel 1) Connect a DC power supply (0 to 20V or above, 5A MOSFET (M1) when the input voltage exceeds the pro- or depending on load) to VIN1 and GND. grammed threshold voltage. As soon as the input volt- 2) Connect a voltmeter or oscilloscope and a load (if age drops below the overvoltage threshold, the charge desired) to OUT and GND. pump of the MAX6495 fully enhances MOSFET M1 to 3) Make sure the J2 shunt connects pins 1-2 (overvolt- turn the output back on. The voltage-divider formed by age-protect mode). The J4 shunt should connect R1 and R2 sets the threshold voltage. The resistors pro- pins 1-2. vided in the MAX6495 EV kit set the threshold at 17V. If inputs VIN2 or VIN3 are used, this threshold will be 4) Turn on the power supply and increase the input volt- higher due to the voltage drop in D1 or M2. age. The output turns on when the input voltage reaches 5.5V. Increase the supply voltage further the The overvoltage threshold can be adjusted by varying output turns off when the input voltage reaches 17V. R1 or R2 using the equation below: 5) The above steps can be followed for a power supply connected to VIN2 or VIN3. The thresholds for turn V OV R1 =12R on and turn off for inputs VIN2 and VIN3 are higher 12. 4 due to the voltage drop across the reverse-battery protection. where V is the desired overvoltage threshold. To OV maintain threshold accuracy, R2 must be less than Detailed Description 250k . Since the EV kit ships with R2 set at 49.9k , an The MAX6495 EV kit demonstrates a high-voltage over- easy way to change the threshold is to change R1 only, voltage protection circuit for automotive applications using the formula above. that must survive load dump and high-voltage transient Overvoltage Limiter Mode conditions. This EV kit can be configured in overvoltage In overvoltage limiter mode, the MAX6495 monitors the mode or overvoltage limiter mode by setting jumper J2 output voltage instead of the input voltage. The output (see Table 1 for the jumper settings), and can supply voltage is sensed through the same voltage-divider up to 5A of output current. formed by R1 and R2, so the equation given for over- The MAX6495 EV kit has three positive power-supply voltage mode also applies to the threshold voltage in inputs: VIN1, VIN2, and VIN3. Inputs VIN2 and VIN3 overvoltage limiter mode. During an input overvoltage Component Suppliers SUPPLIER PHONE FAX WEBSITE AVX Corp. 602-678-0384 602-678-0385 www.avx.com Central Semiconductor Corp. 516-435-1110 516-435-1824 www.centralsemi.com Diodes Inc. 805-446-4800 805-446-4850 www.diodes.com Electronic Connector Service, Inc. 714-895-6351 714-894-1858 www.ecsconn.com EPCOS 732-906-4300 732-603-5935 www.epcos.com International Rectifier 310-322-3331 310-322-3332 www.irf.com Murata Mfg. Co., Ltd. 770-436-1300 770-436-3030 www.murata.com STMicroelectronics 408-452-8585 408-452-1549 www.st.com TDK Corp. 847-390-4373 847-390-4428 www.component.tdk.com Vishay 402-563-6866 402-563-6296 www.vishay.com Note: Indicate that you are using the MAX6495 when contacting these component suppliers. 2 Evaluates: MAX6495