Evaluates: MAX17681A for Isolated MAX17681A Evaluation Kit 15V and 7.5V Output Configuration General Description Quick Start The MAX17681E evaluation kit (EV kit) is a fully assembled Recommended Equipment and tested circuit board that demonstrates the One 15V60V DC, 0.5A power supply performance of the MAX17681A high-efficiency, iso-buck, Four resistive loads, each 75mA sink capacity DC-DC converter. The EV kit operates over a wide input- voltage range of 17V to 36V and uses primary-side feed- Four digital multimeters (DMM) back to regulate the output voltage. The EV kit output is Caution: Do not turn on the power supply until all programmed to 15V, 75mA each and 7.5V, 75mA each connections are completed. with 10% regulation. Test Procedure The EV kit comes installed with the MAX17681A in a 1) Verify that J1 is open. 10-pin (3mm x 2mm) TDFN package. 2) Set the power supply output to 24V. Disable the Features power supply. 17V to 36V Input Voltage Range 3) Connect the positive terminal of the power supply 15V, 75mA Each and 7.5V, 75mA Each Continuous to the V PCB pad and the negative terminal to the IN Current nearest PGND PCB pad. EN/UVLO Input 4) Connect the first resistive load across the +15V PCB pad and the GND0 PCB pad. Connect the second 200kHz Switching Frequency 75mA resistive load across the -15V PCB pad and 86.9% Peak Efficiency the GND0 PCB pad. Overcurrent Protection 5) Connect the third 75mA resistive load across the No Optocoupler +7V PCB pad and the GND0 PCB pad. Connect the fourth 75mA resistive load across the -7V PCB pad Delivers Up to 3.4W Output Power and the GND0 PCB pad. Overtemperature Protection 6) Connect two DMMs configured in voltmeter mode Proven PCB layout across the 15V PCB pads and the nearest GND0 Provides robust primary and secondary output short- PCB pad. Also, connect another two DMMs configured circuit protection in voltmeter mode across the 7 PCB pads and the nearest GND0 PCB pad. 7) Enable the input power supply. Ordering Information appears at end of data sheet. 8) Verify that output voltages are at 15V and 7.5V (with allowable tolerance of 10%) with respect to GND0. 9) If required, vary the input voltage from 17V to 36V, and the load current from 0mA to 75mA and verify that output voltages are 15V and 7.5V. 19-8801 Rev 0 3/17MAX17681A Evaluation Kit Evaluates: MAX17681A for Isolated 15V and 7.5V Output Configuration procedure for setting the soft-start time, ENABLE/UVLO Detailed Description divider, primary output voltage (V ) selection, adjusting PRI The MAX17681E EV kit is a fully assembled and tested the primary output voltage, primary inductance selection, circuit board that demonstrates the performance of the turns-ratio selection, output capacitor selection, output MAX17681A high-efficiency, iso-buck, DC-DC converter diode selection and external loop compensation are given designed to provide an isolated power up to 3.4W. The in the MAX17681 IC data sheet. EV kit generates either 15V or 7.5V, 75mA each output voltages, from a 17V to 36V input supply. The EV Enable Control (J1) kit features a forced-PWM control scheme that provides The EN/UVLO pin on the device serves as an on/ constant switching-frequency of 200kHz operation at all off control while also allowing the user to program the load and line conditions. input undervoltage lockout (UVLO) threshold. Jumper J1 The EV Kit includes an EN/UVLO PCB pad to monitor and configures the EV kits output for turn-on/turn-off control. program the EN/UVLO pin of the MAX17681A. The V Install a shunt across jumper J1 pins 2-3 to disable V . PRI OUT PCB pad helps measure the regulated primary output See Table1 for proper J1 jumper configurations. voltage (V ). An additional RESET PCB pad is available PRI NOTE 1: The secondary output diodes D1, D2, D3, and for monitoring the health of primary output voltage (V ). PRI D4 are rated to carry short-circuit current only for few RESET pulls low if FB voltage drops below 92.5% of 100s of ms and is not rated to carry the continuous short- its set value. RESET goes high-impedance 1024 clock circuit current. cycles after FB voltage rises above 95.5% of its set NOTE 2: The iso-buck converter typically needs 10% value. The programmable soft-start feature allows users minimum load to regulate the output voltage. In this to reduce the input inrush current. design when the +24V rail is healthy, the U2, U3 sinks The iso-buck is a synchronous-buck-converter-based the minimum load current required to regulate the output topology, useful for generating isolated outputs at low voltages within 10% regulation. power level without using an optocoupler. The detailed Table1. Enable Control (EN/UVLO) (J1) Jumper Settings SHUNT POSITION EN/UVLO PIN VOUT OUTPUT J1 1-2 Connected to V Enabled IN 2-3 Connected to GND Disabled Open* Connected to midpoint of R1, R2 resistor-divider Enabled at V 15.5V IN *Default position. Maxim Integrated 2 www.maximintegrated.com