MAX20457EVKIT# Analog Devices

Click here for production status of specific part numbers. Evaluates: MAX20457 MAX20457 Evaluation Kit General Description Quick Start The MAX20457 evaluation kit (EV kit) is a fully assembled Required Equipment and tested application circuit that simplifies the evalu - MAX20457 EV kit ation of the MAX20457 2.1MHz dual buck converters. 15V, 7A DC power supply (PS1) All installed components are rated for the automotive temperature range. Various test points and jumpers are Two voltmeters (VM1 and VM2) included for evaluation. Two electronic loads (EL1 and EL2) The standard EV kit comes with the MAX20457ATIE/VY+ Procedure installed (5V, 3.3V, 2.1MHz) and can also be used to eval- The EV kit is fully assembled and tested. Follow the steps uate other MAX20457 variants with minimal component below to verify board operation. changes shown in the MAX20457 EV Kit Bill of Materials. Caution: Do not turn on the power supply until all Benefits and Features connections are completed. Dual High-Voltage Step-Down Converters with 1) Verify that all jumpers are in their default positions as Integrated Power FETs to Minimize Board-Area shown in Table 1. Occupancy 2) Preset the power supply PS1 to 14V. Turn off the PS1. 3.5V to 40V Input Supply Range 3) Preset EL1 to 3A. Turn off the EL1. 4) Preset EL2 to 1.5A. Turn off the EL2. Buck1 Provides 5V Output up to 3.5A Output Current 5) Connect the positive terminal of EL1 to V con- OUT1 Buck2 Provides 3.3V Output up to 2A Output Current nect the negative terminal of EL1 to PGND1. Buck Output Voltages Adjustable Between 1V and 6) Connect the positive terminal of EL2 to V con- OUT2 14V using External Resistors nect the negative terminal of EL2 to PGND2. 7) Connect the positive terminal of PS1 to the V BATTF 2% Output Voltage Accuracy for Buck Converters connect the negative terminal of PS1 to GND3. Selectable Buck2 Input Source 8) Connect the positive terminal of VM1 to V con- OUT1 Frequency-Synchronization Input nect the negative terminal of VM1 to PGND1. 9) Connect the positive terminal of VM2 to V con- OUT2 Independent Enable Inputs nect the negative terminal of VM2 to PGND2. Voltage-Monitoring PGOOD Outputs 10) Turn on the power supply. Jumpers and Test Points on Key Nodes for Simplified 11) Enable the electronic loads, EL1 and EL2. Evaluation 12) Verify that the voltmeter on V measures ap- OUT1 proximately 5V. Proven PCB Layout 13) Verify that the voltmeter on V measures ap- OUT2 Fully Assembled and Tested proximately 3.3V. Ordering Information appears at end of data sheet. 319-100398 Rev 0 7/19Evaluates: MAX20457 MAX20457 Evaluation Kit Table 1. Default Jumper Settings JUMPER SHUNT POSITION FUNCTION JU3 EN1 1-2 Buck1 controller enabled JU2 EN2 1-2 Buck2 controller enabled JU2 SUPSW2 2-3 Buck2 input supplied by V BATTF JU4 FSYNC 1-2 FSYNC is pulled to V enabling FPWM mode BIAS JU PGOOD1 Installed PGOOD1 is pulled up to V when OUT1 is in regulation BIAS JU PGOOD2 Installed PGOOD2 is pulled up to V when OUT2 is in regulation BIAS JU5 EXTVCC 1-4 EXTVCC is connected to V OUT1 To obtain logic signals, pull up PGOOD1 and PGOOD2 Detailed Description to V by installing the shunts on jumpers on JU BIAS The MAX20457 EV kit provides a fully developed and PGOOD1 and JU PGOOD2. proven layout for evaluating all variants of the MAX20457 family of current-mode-controlled buck converter ICs. Setting the Output Voltage in Each converter accepts input supply voltages as high as Buck Converters 36V and input supply transients up to 40V. The EV kit comes preassembled to provide a fixed 5V voltage regulation on V . To externally adjust the Switching Frequency and OUT1 voltage at V , remove R1 and place appropriate External Synchronization OUT1 resistors in positions R3 and R4 according to the follow- The IC can operate in two modes, forced-PWM or skip mode. ing equation: Skip mode offers improved efficiency over PWM during light- load conditions. When FSYNC is pulled low, the device oper- VOUT1 R3 R4 1 ates in skip mode for light loads, and in PWM mode for larger VFB loads. When FSYNC is pulled high, the device is forced to operate in PWM across all load conditions. where VFB = 1V (typ) and R4 = 50k. The FSYNC pin can be used to synchronize the switching The EV kit comes preassembled to provide a fixed 3.3V frequency of the IC to an external source by applying an voltage regulation on V . To externally adjust the volt- OUT2 external clock signal. The device is forced to operate in age at V , remove R12 and place appropriate resis- OUT2 PWM when FSYNC is connected to a clock source. tors in positions R15 and R16 according to the following equation: Buck Output Monitoring (PGOOD ) The EV kit provides output test points (PGOOD1 and VOUT2 R15 R16 1 PGOOD2) to monitor the status of the respective buck VFB2 output voltage on V and V . PGOOD is high OUT1 OUT2 impedance when the respective output voltage rises where VFB2 = 1V (typ) and R16 = 50k. above its 95% (typ) of regulation voltage. PGOOD goes low when the respective output voltage drops below 93.5% (typ) of its nominal regulated voltage. Maxim Integrated 2 www.maximintegrated.com = =