MAX17681 Evaluation Kit General Description The MAX17681 evaluation kit (EV kit) is a fully assembled and tested circuit board that demonstrates the performance of the MAX17681 high-efficiency, iso-buck DC-DC converter. The EV kit operates over a wide input voltage range of 17V to 32V and uses primary-side feedback to regulate the output voltage. The EV kit has two output configurations. In the first configuration, the output is programmed to ±15V at 100mA, with ±10% output-voltage regulation. The second configuration uses a post regulator (MAX17651) to produce ±12V at 50mA with < ±3% regulation. The EV kit comes installed with the MAX17681 in a 10-pin (3mm x 2mm) TDFN package and MAX17651 in a 6-pin TSOT package. Features ●● 17V to 32V Input Voltage Range ●● ±15V, 100mA or ±12V, 50mA Continuous Current ●● EN/UVLO Input ●● 200kHz Switching Frequency ●● 90% Peak Efficiency ●● Overcurrent Protection ●● No Optocoupler ●● Delivers Up to 3W Output Power ●● Overtemperature Protection ●● Proven PCB layout Evaluates: MAX17681 for Isolated ±15V or ±12V Output Configuration Quick Start Recommended Equipment ●● One 15V to 60V DC, 0.5A power supply ●● Two loads of 50mA to 100mA sink capacity ●● Four digital multimeters (DMM) Caution: Do not turn on the power supply until all connections are completed. Procedure The EV kit comes with default output configuration programmed to ±15V. Test Procedure for ±15V Output 1) Verify that jumper JU1 is open. 2) Verify that the R17–R19 are not installed. 3) Set the power-supply output to 24V. Disable the power supply. 4) Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the nearest PGND PCB pad. Connect the positive terminal of the first 100mA load to the +15V PCB pad and the negative terminal to the nearest GND0 PCB pad. Connect the positive terminal of the second 100mA load to the GND0 PCB pad and the negative terminal to the nearest -15V PCB pad. 5) Connect a DMM configured in voltmeter mode across the +15V PCB pad and the nearest GND0 PCB pad. Connect another DMM configured in voltmeter mode across the -15V PCB pad and the nearest GND0 PCB pad. 6) Enable the input power supply. Ordering Information appears at end of data sheet. 7) Enable the loads and verify that the output voltage is at ±15V with respect to GND. 8) If required, vary the input voltage from 17V to 32V, the load current from 0 to 100mA, and verify that the output voltage is ±15V. 19-7634; Rev 1; 6/15 Evaluates: MAX17681 for Isolated ±15V or ±12V Output Configuration MAX17681 Evaluation Kit Detailed Description Test Procedure for ±12V Output 1) Verify that JU1 is open. 2) Remove R16 and R10. Place 0Ω resistors in R18 and R19. Place a 681kΩ pack-out resistor (comes with EV kit package) in R17. 3) Set the power-supply output to 24V. Disable the power supply. 4) Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the nearest PGND PCB pad. Connect the positive terminal of the first 50mA load to the +12V PCB pad and the negative terminal to the nearest GND0 PCB pad. Connect the positive terminal of the second 50mA load to the GND0 PCB pad and the negative terminal to the nearest -12V PCB pad. 5) Connect a DMM configured in voltmeter mode across the +12V PCB pad and the nearest GND0 PCB pad. Connect another DMM configured in voltmeter mode across the -12V PCB pad and the nearest GND0 PCB pad. 6) Enable the input power supply. 7) Enable the loads and verify that the output voltage is at ±12V with respect to GND. 8) If required, vary the input voltage from 17V to 32V, the load current from 0 to 50mA, and verify that the output voltage is ±12V. The EV kit is a fully assembled and tested circuit board that demonstrates the performance of the MAX17681 high-efficiency, iso-buck DC-DC converter designed to provide isolated power up to 3W. The EV kit generates either ±15V, 100mA or ±12V, 50mA output voltages from a 17V to 32V input supply. The EV kit features a forcedPWM control scheme that provides constant switchingfrequency of 200kHz operation at all load and line conditions. The EV kit includes an EN/UVLO PCB pad to enable control of the converter output. The VPRI PCB pad helps measure the regulated nonisolated buck voltage. An additional RESET PCB pad is available for monitoring FB regulated voltage, the open-drain logic output. The programmable soft-start feature allows users to reduce input inrush current. The iso-buck is a synchronous-buck-converter-based topology, useful for generating isolated outputs at low power level without using an optocoupler. The detailed procedure for setting the soft-start time, ENABLE/UVLO divider, primary output-voltage (VPRI) selection, adjusting the primary output voltage, primary inductance selection, turns-ratio selection, output capacitor selection, output diode selection, and external loop compensation are given in the MAX17681 IC data sheet. The post-regulator MAX17651 output-voltage setting and additional related information are detailed in the MAX17651 IC data sheet. Enable Control (JU1) The EN/UVLO pin on the device serves as an on/off control while also allowing the user to program the input undervoltage-lockout (UVLO) threshold. JU1 configures the EV kit’s output for on/off control. Install a shunt across JU1 pins 2-3 to disable VOUT. See Table 1 for proper JU1 jumper configurations. Table 1. Enable Control (EN/UVLO) (JU1) Jumper Settings SHUNT POSITION EN/UVLO PIN VOUT OUTPUT 1-2 Connected to VIN Enabled 2-3 Open* *Default position. www.maximintegrated.com Connected to GND Disabled Connected to midpoint of R1, R2 resistor-divider Enabled at VIN ≥ 15.5V Maxim Integrated │ 2 Evaluates: MAX17681 for Isolated ±15V or ±12V Output Configuration MAX17681 Evaluation Kit EV Kit Performance Report EFFICIENCY vs. LOAD CURRENT 100 toc1 OUTPUT VOLTAGE vs. LOAD CURRENT 17.00 90 16.50 70 VIN = 32V 60 OUTPUT VOLTAGE (V) EFFICIENCY (%) 80 VIN = 24V 50 VIN = 17V 40 30 20 16.00 VIN = 32V VIN = 17V ±15V OUTPUT 0 10 20 30 40 50 60 70 80 14.50 90 100 0 20 LOAD CURRENT (mA) 12.21 -14.8 12.20 -15 -15.2 VIN = 17V -15.4 VIN = 24V VIN = 32V -15.8 -16 100 toc4 VIN = 17V 12.19 12.18 VIN = 24V 12.17 VIN = 32V 12.16 12.15 12.14 0 20 40 60 80 100 12.13 LOAD CURRENT (mA) 0 10 20 toc5 50 +15V output VIN = 17V -12.15 40 LOAD TRANSIENT RESPONSE (LOAD CURRENT FROM 50mA TO 100mA ON +15V, -15V LOADED WITH 100mA ) toc6 -12V OUTPUT -12.14 30 LOAD CURRENT (mA) OUTPUT VOLTAGE vs. LOAD CURRENT -12.13 OUTPUT VOLTAGE (V) 80 +12V output 12.22 -14.6 -15.6 60 OUTPUT VOLTAGE vs. LOAD CURRENT 12.23 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) toc3 -15V output -14.4 40 LOAD CURRENT (mA) OUTPUT VOLTAGE vs. LOAD CURRENT -14.2 -16.2 VIN = 24V 15.50 15.00 10 0 toc2 +15V output -12.16 -12.17 VIN = 32V -12.18 VOUT (AC) VIN = 24V 500mV/div -12.19 -12.20 -12.21 IOUT 50mA/div -12.22 -12.23 0 10 20 30 LOAD CURRENT (mA) www.maximintegrated.com 40 50 400µS/div Maxim Integrated │ 3 MAX17681 Evaluation Kit Figure 1. MAX17681 EV Kit Component Placement Guide— Component Side Evaluates: MAX17681 for Isolated ±15V or ±12V Output Configuration Figure 2. MAX17681V EV Kit PCB Layout—Component Side Figure 3. MAX17681 EV Kit PCB Layout—Solder Side www.maximintegrated.com Maxim Integrated │ 4 MAX17681 Evaluation Kit Evaluates: MAX17681 for Isolated ±15V or ±12V Output Configuration Component Suppliers SUPPLIER WEBSITE Wurth Electronik www.we-online.com Murata Americas www.murata.com Panasonic Corp. www.panasonic.com Note: Indicate that you are using the MAX17681 when contacting these component suppliers. Component List and Schematic See the following links for component information and schematic: ●● MAX17681 EV BOM ●● MAX17681 EV Schematic www.maximintegrated.com Ordering Information PART TYPE MAX17681EVKIT# EV Kit #Denotes RoHS compliant. Maxim Integrated │ 5 MAX17681 Evaluation Kit Evaluates: MAX17681 for Isolated ±15V or ±12V Output Configuration Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 5/15 Initial release — 1 6/15 Updated Typical Operating Characteristics section, BOM, and schematic 1-3 DESCRIPTION For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2015 Maxim Integrated Products, Inc. │ 6 +15V A D1 U2 R18 C VPRI OPEN C7 0.1UF R9 R10 2.2UF C12 562 22K 3 IN OUT 4 2 GND PGOOD 5 1 EN 6 FB +12V R12 909K C9 2.2UF MAX17651 GND0 R13 T1 4 VIN VIN EN/UVLO 1 R1 C2 3.01M 2 3 J1 1UF C14 0.01UF R2 261K VCC 2 VIN 3 4 5 LX GND EN/UVLO RESET VCC FB 10 PRI RESET 8 8 R16 1 VCC 8 COMP 7 SS 6 R6 RESET R5 C5 680PF C6 100K 10UF R11 R3 90.9K R17 PACKOUT C8 2.2UF 4.75K C4 0.033UF EP C3 931K C D2 A 2 1 4 R8 82.5K R4 0.033UF 10.5K -15V EN/UVLO C11 1000PF RESET SGND PGND PGND GND0 GND0 U3 OPEN C13 R7 22K U4 GND0 GND0 R19 9 SGND EN/UVLO 7 6 7 3 1UF PGND 1 6 GND0 5 C1 1 11 C15 22UF 1 + 2 U1 MAX17681ATB+ 4 5 0 PGND 5 47.5K 0.1UF 3 IN OUT 4 2 GND PGOOD 5 1 EN FB 6 R14 909K C10 2.2UF MAX17651 R15 47.5K -12V S NO Designation Qty Description 1 C1 1 1µF±10%, 50V,X7R Ceramic capacitor (1206) 2 C2 1 1µF±10% 16V X7R Ceramic capacitor (0603) 3 C3,C4 2 33nF±10%,25V, X7R ceramic capacitor (0402) 4 C5 1 680pF±5%,50V,X7R ceramic capacitor (0402) 5 C6 1 10uF±10%,16V, X7R ceramic capacitor (1206) 2.2uF±10%,50V, X7R ceramic capacitor (1206) 1000PF ±10%,1500V, X7R ceramic capacitor (1206) Manufacturer Partnumber-1 Murata GRM31CR71H105KA61 Murata GRM188R71C105KA12 Manufacturer Partnumber-2 Manufacturer Partnumber-3 Manufacturer Partnumber-4 KEMET C1206C105K5RAC Murata GRM31MR71H105KA88 KEMET C0603C105K4RAC TDK C1608X7R1C105K TAIYO YUDEN EMK107B7105KA TDK C1005C0G1H681G050 VENKEL LTD C0402C0G500-681JNP Murata GRM1555C1H681GA01 Murata GRM155R71E333KA88 Murata GRM1555C1H681JA01 Murata GRM31CR71C106KAC7 6 C7,C8,C9,C10 4 7 C11 1 8 C12,C13 2 0.1uF±10%, 25V, C0G ceramic capacitor(0402) Murata GRM155R71E104KE14 9 C14 1 0.01uF±10%, 50V, X7R ceramic capacitor (0402) Murata GRM155R71H103KA88 10 C15 1 22uF, 20%, 50V, ALUMINUM ELECTROLYTIC CAPACITOR 6.60*6.60mm Murata GRM31CR71H225KA88 TAIYO YUDEN UMK316B7225K AVX 1206SC102KAT KEMET C0402C103K5RAC Panasonic EEEFK1H220P SULLINS ELECTRONICS CORP PEC03SAAN 11 JU1 1 3-pin headers 12 D1,D2 2 200V/1A, PowerDI®123 13 R1 1 3.01M Ohm±1% resistor (0402) 14 R2 1 261K Ohm±1% resistor (0402) VISHAY DALE CRCW0402261KFK 15 R3 1 90.9K Ohm±1% resistor (0402) PANASONIC ERJ-2RKF9092X 16 R4 1 10.5kΩ ±1% resistor (0402) PANASONIC ERJ-2RKF1052 17 R5 1 4.75kΩ ±1% resistor (0402) VISHAY DALE CRCW04024K75FK 18 R6 1 100kΩ ±5% resistor (0402) PANASONIC ERJ-2GEJ104X 19 R7,R9 2 22kΩ ±1% resistor (0402) 20 R8 1 82.5kΩ ±1% resistor (0402) 21 R10 1 562Ω ±1% resistor (0402) PANASONIC ERJ-2RKF5620X 22 R11 1 931kΩ ±1% resistor (0402) VISHAY DALE CRCW0402931KFK 23 R12,R14 2 909kΩ ±1% resistor (0402) VISHAY DALE CRCW0402909KFK Diode Inc. DFLS1200-7 VISHAY DALE CRCW04023M01FK VISHAY DALE CRCW040222K0FK VISHAY DALE CRCW040282K5FK BOURNS CR0402-FX8252GLF 24 R13,R15 2 47.5kΩ ±1% resistor (0402) 25 R16 1 0Ω ±5% resistor (0805) 26 R17 1 OPEN 27 R18,R19 2 VISHAY DALE CRCW04024752FK YAGEO PHYCOMP RC0805JR070RL OPEN EP10, 8-pin SMT, 50µH,1.4A, (1-4):(5-6):(7-8) = 1:1.8:1.8 MAX17681 TDFN10 3*2mm Iso buck DC-DC converter WURTH ELECTRONICS INC. 750342557 28 T1 1 29 U1 1 30 U2,U3 1 MAX17651 TSOT LDO MAX17651AZT+ 31 U4 1 Shunt regulator SOT25 Diode Inc. TL431BW5 MAX17681ATB+ VISHAY DALE 9C04021A4752FLHF3 VISHAY DALE CRCW040247K5FK