Evaluates: MAX6496 19-0999 Rev 0 9/07 MAX6496 Evaluation Kit General Description Features The MAX6496 evaluation kit (EV kit) demonstrates a high- 5.5V to 72V Wide Supply Voltage Range voltage, overvoltage-protection circuit for automotive Up to 5A Output Current Capacity applications that must survive load-dump and high-volt- age transient conditions. This EV kit is a fully assembled Selectable Overvoltage Mode and Overvoltage- and tested surface-mount printed-circuit board (PCB). Limiter Mode The MAX6496 EV kit supports high-output currents of Adjustable Overvoltage Threshold up to 5A and can run at voltages up to 72V. An on- board p-channel MOSFET provides reverse-battery 100V Reverse-Battery Protection protection. Ordering Information PART TYPE MAX6496EVKIT+ EV Kit +Denotes lead-free and RoHS-compliant. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION 22F 20%, 100V aluminum 100V, 23A p-channel MOSFET C1, C2 2 electrolytic capacitors Q1 1 International Rectifier IRF9540NSPBF Vishay 222215369229 Fairchild FQB22P10TM NL 100V, 33A n-channel MOSFET 0.1F 10%, 100V X7R ceramic Q2 1 International Rectifier IRF540NSPBF capacitor (1206) C3 1 Fairchild FQB33N10TM NL TDK C3216X7R2A104K R1 1 649k 1% resistor (0805) AVX 12061C104KAT2A R2 1 49.9k 1% resistor (0805) C4 0 Not installed, capacitor (1206) R3 0 Not installed, resistor (0805) J1, J2, J3 3 3-pin headers U1 1 MAX6496ATA+ (8-pin TDFN) 1 PCB: MAX6496 Evaluation Kit+ Component Suppliers SUPPLIER PHONE FAX WEBSITE AVX Corp. 602-678-0384 602-678-0385 www.avx.com Fairchild Semiconductor 888-522-5372 Local Rep Only www.fairchildsemi.com International Rectifier 310-322-3331 310-322-3332 www.irf.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 MAX6496 when contacting these component suppliers. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX6496 Evaluation Kit Overvoltage Mode Quick Start In overvoltage mode, the MAX6496 monitors the input Recommended Equipment voltage and turns off the series-pass n-channel MOSFET Before beginning, the following equipment is needed: (Q2) when the input voltage exceeds the programmed DC power supply (0 to 20V or above, 5A) threshold voltage. As soon as the input voltage drops below the overvoltage threshold, the charge pump of Voltmeter or oscilloscope the MAX6496 fully enhances MOSFET Q2 to turn the Procedure output back on. The voltage-divider formed by R1 and The MAX6496 EV kit is fully assembled and tested. R2 sets the threshold voltage. The resistors provided in Follow the steps below to verify board operation. the MAX6496 EV kit set the threshold at 17.4V. If input Caution: Do not turn on the power supply until all IN2 is used, the threshold will be slightly higher due to connections are completed. the voltage drop across Q1. 1) Connect a DC power supply (0 to 20V or above, 5A The overvoltage threshold can be adjusted by varying or depending on load) to IN1 and GND. resistors R1 or R2 using the equation below: 2) Connect a voltmeter or oscilloscope and a load V OV (if desired) to OUT and GND. R1=12 R 12. 4 3) Make sure the J3 shunt connects pins 2-3 (overvolt- age mode). The J1 shunt should connect pins 1-2, where V is the desired overvoltage threshold. To OV and the J2 shunt should connect pins 1-2. maintain threshold accuracy, R2 must be less than 4) Turn on the power supply and increase the input volt- 250k . Since the EV kit ships with R2 set at 49.9k, an age. The output turns on when the input voltage easy way to change the threshold is to change R1 only, reaches 5.5V. Increase the supply voltage further the using the formula above. output turns off when the input voltage reaches 17.4V. Overvoltage-Limiter Mode 5) The steps above can be followed for a power sup- In overvoltage-limiter mode, the MAX6496 monitors the ply connected to IN2. The thresholds for turn-on output voltage instead of the input voltage. The output and turn-off are higher due to the voltage drop voltage is sensed through the same voltage-divider across the reverse-battery protection. formed by resistors R1 and R2, so the equation given for Detailed Description overvoltage mode also applies to the threshold voltage in the overvoltage-limiter mode. During an input- The MAX6496 EV kit demonstrates a high-voltage, over- overvoltage transient in this mode, the MOSFET switches voltage-protection circuit for automotive applications off until the output voltage falls to 95% of the threshold that must survive load-dump and high-voltage transient voltage, and then the MOSFET switches back on. This conditions. The MAX6496 EV kit can be configured in cycle repeats, generating a sawtooth waveform on overvoltage mode or overvoltage-limiter mode by set- the output. ting jumper J3 (see Table 1 for jumper settings) and can supply up to 5A of output current. The minimum output voltage in overvoltage-limiter mode depends on load current, output capacitance, The MAX6496 EV kit has two positive power-supply and the MOSFETs switching period. The MAX6496 EV inputs, IN1 and IN2. Input IN2 connects to the p-chan- kit comes with one 22F capacitor at the output to sup- nel MOSFET for reverse-battery protection input IN1 ply the load during the time when the MOSFET is off. bypasses the MOSFET. Add capacitor C4 on the gate of MOSFET Q2 to decrease the frequency of the sawtooth waveform. This Table 1. Jumper Settings (J1, J2, and J3) helps limit the devices power dissipation. SHUNT POSITION AND FUNCTION JUMPER Jumper Selection 1-2 2-3 Jumper J3 selects between overvoltage mode and J1 U1 enabled* U1 disabled overvoltage-limiter mode do not leave this jumper J2 Q1 gate drive enabled* Q1 gate drive disabled unconnected. Jumper J2 controls the gate drive of J3 Overvoltage-limiter mode Overvoltage mode* p-channel MOSFET Q1, used as reverse-battery protec- tion. Use J2 to disconnect the MAX6496 from Q1 when *Default position. 2 Evaluates: MAX6496