MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V Output Configuration General Description The MAX78EVKITC is a fully assembled and tested circuit board that demonstrates the performance of the MAX78 high-efficiency, iso-buck DC-DC converter. The EV kit operates over a wide input-voltage range of 7V to V 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 +V at 00mA, with ±8% output voltage regulation. The second configuration uses a post regulator (MAX7) to produce +V at 00mA with better than ±% regulation. The EV kit comes installed with the MAX78 in a 0-pin (mm x mm) TDFN package and MAX7 in a -lead Thin-SOT (TSOT) package. Features 7V to V Input Voltage Range +V, 00mA or +V, 00mA Continuous Current EN/UVLO Input 00kHz Switching Frequency 89.% Peak Efficiency Overcurrent Protection No Optocoupler Delivers up to W Output Power Overtemperature Protection Proven PCB layout Provides robust primary and secondary output short-circuit protection Ordering Information appears at end of data sheet. Quick Start Recommended Equipment One V 0V DC, 0.A power supply Two resistive loads of 00mA 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 the default output configuration programmed to +V. Test Procedure for +V Output ) Verify that the J is open ) Verify that the R7 and R is not installed ) Set the power supply output to V. Disable the power supply ) Connect the positive terminal of the power supply to the V IN PCB pad and the negative terminal to the nearest PGND Connect a 00mA resistive load across the +V PCB pad and the ) Connect a DMM configured in voltmeter mode across the +V PCB pad and the nearest ) Enable the input power supply. 7) Verify that output voltage is at +V (with allowable tolerance of ±8%) with respect to. 8) If required, vary the input voltage from 7V to V, and the load current from 0mA to 00mA and verify that output voltage is at +V (with allowable tolerance of ±8%). 9-8; Rev ; 8/7
MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V Output Configuration Test Procedure for +V Output ) Verify that the J is open ) Place 0Ω resistors in R7, Place a 8k pack-out resistor (comes with EV kit package) in R. ) Set the input power supply output to V. Disable the power supply ) Connect the positive terminal of the power supply to the V IN PCB pad and the negative terminal to the nearest PGND Connect a 00mA resistive load across the +V PCB pad and the ) Connect a DMM configured in voltmeter mode across the +V PCB pad and the nearest ) Enable the input power supply. 7) Verify that output voltage is at +V (with allowable tolerance of ±%) with respect to. 8) If required, vary the input voltage from 7V to V, and the load current from 0mA to 00mA and verify that output voltage is at +V (with allowable tolerance of ±%). Detailed Description The MAX78EVKITC evaluation kit (EV kit) is a fully assembled and tested circuit board that demonstrates the performance of the MAX78 high-efficiency, iso-buck DC-DC converter designed to provide an isolated power up to W. The EV kit generates either +V, 00mA or +V, 00mA from a 7V to V input supply. The EV kit features a forced PWM control scheme that provides constant switching-frequency of 00kHz operation at all load and line conditions. The EV Kit includes an EN/UVLO PCB pad to monitor and program the EN/UVLO pin of the MAX78. The V PRI PCB pad helps measure the regulated primary output voltage (V PRI ). An additional RESET PCB pad is available for monitoring the health of primary output voltage (V PRI ). RESET is pulled low if FB voltage drops below 9.% of its set value. RESET goes high 0 clock cycles after FB voltage rises above 9.% of its set value. The programmable soft-start feature allows users to reduce the 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 (V PRI ) 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 MAX7 IC data sheet. The MAX7 s output voltage setting, and related additional information, are detailed in MAX7 IC data sheet. Enable Control (J) 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. J configures the EV kit s output for turn-on/turn-off control. Install a shunt across J pins - to disable VOUT. See Table for proper J configurations. NOTE : The secondary output diode (D) is rated to carry the short-circuit current only for few 00 s of ms and is not rated to carry the continuous short-circuit current. NOTE : The iso-buck converter typically needs 0% minimum load to regulate the output voltage. In this design, when the +V rail is healthy, the U sinks the minimum load current required to regulate the output voltages within ±8% regulation. Table. Enable Control (EN/UVLO) (J) Jumper Settings SHUNT POSITION EN/UVLO PIN VOUT J - Connected to V IN Always Enabled - Connected to GND Always Disabled Open* Connected to midpoint of R, R resistor-divider Enabled at V IN.V *Default position. Maxim Integrated
MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V Output Configuration EV Kit Performance Report EFFICIENCY (%) 00 90 80 70 0 0 0 0 0 EFFICIENCY vs. LOAD CURRENT toc0 V IN = 7V V IN = V V IN = V 0 +V OUTPUT 0 0 0 0 0 80 00 0 0 0 80 00 OUTPUT VOLTAGE (V)..0.8....0.8.. OUTPUT VOLTAGE vs. LOAD CURRENT toc0 V IN = 7V V IN = V. 0 0 0 0 80 00 0 0 0 80 00 +V OUTPUT V IN = V EFFICIENCY (%) 90 80 70 0 0 0 0 0 EFFICIENCY vs. LOAD CURRENT toc0 V IN = 7V V IN = V V IN = V 0 +V OUTPUT 0 0 0 0 0 0 0 0 70 80 90 00 OUTPUT VOLTAGE (V)...0.08.0.0.0 OUTPUT VOLTAGE vs. LOAD CURRENT toc0 V IN = 7V V IN = V.00 0 0 0 0 80 00 +V OUTPUT V IN = V LOAD TRANSIENT RESPONSE (LOAD CURRENT FROM 00mA TO 00mA ON +V) toc0 V OUT (AC) 00mV/div 00mA/div I OUT +V OUTPUT 00µS/div Maxim Integrated
MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V 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 MAX78 when contacting these component suppliers. Ordering Information PART MAX78EVKITC# #Denotes RoHS compliant. TYPE EVKIT MAX78 EV Kit Bill of Materials S NO Designation Qty Description Manufacturer Partnumber- Manufacturer Partnumber- Manufacturer Partnumber- Manufacturer Partnumber- C C C,C C C C7, C8,C9 7 C0 8 C µf±0%, 0V,X7R Ceramic capacitor (0) Murata GRMCR7H0KA KEMET C0C0KRAC Murata GRMMR7H0KA88 µf±0% V X7R Ceramic capacitor (00) Murata GRM88R7C0KA KEMET C00C0KRAC TDK C08X7RC0K TAIYO YUDEN EMK07B70KA 0.0UFnF±0%,V, X7R ceramic capacitor (00) Murata GRMR7EKA88 80pF±%,0V,COG ceramic capacitor (00) Murata GRMCH8JA0 VENKEL LTD C00C0G00-8JNP 0uF±0%,V, X7R ceramic capacitor (0) Murata GRMCR7C0KAC7.uF±0%,0V, X7R ceramic capacitor (0) Murata GRMCR7HKA88 TAIYO YUDEN UMKB7K 0.uF±0%, V, X7R ceramic capacitor(00) Murata GRMR7E0KE 0.0uF±0%, 0V, X7R ceramic capacitor (00) Murata GRMR7H0KA88 KEMET C00C0KRAC 9 uf, 0%, 0V, ALUMINUM C ELECTROLYTIC CAPACITOR.0*.0mm, Panasonic EEEFKH0P 0 C 000pF±0%, 00V, X7R ceramic capacitor (0) AVX 0SC0KAT D 00V/A, PowerDI Diode Inc. DFLS00 J -pin headers SULLINS ELECTRONICS CORP PEC0SAAN R.0M Ohm±% resistor (00) VISHAY DALE CRCW00M0FK R K Ohm±% resistor (00) VISHAY DALE CRCW00KFK R 90.9K Ohm±% resistor (00) PANASONIC ERJ-RKF909X R 0.kΩ ±% resistor (00) PANASONIC ERJ-RKF0 7 R.7kΩ ±% resistor (00) VISHAY DALE CRCW00K7FK 8 R 00kΩ ±% resistor (00) PANASONIC ERJ-GEJ0X 9 R7 OPEN (00) 0 R8 0kΩ ±% resistor (00) VISHAY DALE CRCW000KFK R9 kω ±% resistor (00) VISHAY DALE CRCW00K0FK R0 Ω ±% resistor (00) VISHAY DALE CRCW00R0FK R kω ±% resistor (00) VISHAY DALE CRCW00KFK R 909kΩ ±% resistor (00) VISHAY DALE CRCW00909KFK R 7.kΩ ±% resistor (00) VISHAY DALE CRCW007FK R 00 PACKOUT 7 T EP0,8 pinsmt,0μh,.a,( 7):( 8):( )=.8:.8: WURTH ELECTRONICS INC. 7089 8 U MAX78 TDFN0 *mm Iso buck DC- DC converter MAX78ATB+ 9 U MAX7 TSOT LDO MAX7AZT+ 0 U Shunt regulator SOT Diode Inc. TLBW VISHAY DALE 9C00A7FLHF VISHAY DALE CRCW007KFK Maxim Integrated
MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V Output Configuration MAX78 EV Kit System Schematic SGND PGND PGND R K R8 0K U SGND RESET C UF C UF R C C R C 0.0UF R R.7K C 80PF C 0.0UF C VPRI R R 0.K R T C 7 8 +V A D C C7 C8.UF.UF U R0 R7 R9 C0 0.UF R R 7.K C9.UF +V EN/UVLO PGND VIN J U MAX78ATB+ PGND LX 0 VIN GND 9 RESET EN/UVLO RESET 8 VCC COMP 7 FB SS 7089.0M 0.0UF EN/UVLO RESET VIN EN/UVLO UF K VCC EP VCC 00K 0UF 90.9K PRI PACKOUT 000PF OPEN K IN OUT GND PGOOD EN FB MAX7AZT+ 909K 7 8 + Maxim Integrated
MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V Output Configuration MAX78 EV Kit System PCB Layout Diagrams MAX78 EV Kit Top Silkscreen MAX78 EV Kit Top Layer MAX78 EV Kit Bottom Layer Maxim Integrated
MAX78 Evaluation Kit Evaluates: MAX78 for Isolated +V or +V Output Configuration Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 / Initial release / Updated General Description and Bill of Materials. 8/7 Updated General Description and replaced TOC0, For pricing, delivery, and ordering information, please contact Maxim Direct at -888-9-, or visit Maxim Integrated s website at. 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. 07 Maxim Integrated Products, Inc. 7