Click here for production status of specific part numbers. Evaluates: MAX25431 MAX25431 Evaluation Kit General Description Quick Start The MAX25431 evaluation kit (EV kit) is a fully assembled Required Equipment and tested application circuit for the MAX25431 current- MAX25431 EV kit mode buck-boost controller IC. The EV kit is designed to 6V to 36V, 20A power supply deliver up to 16A (max) input current with input voltages from 6V to 36V. The voltage quality can be monitored by Voltmeter observing the PGOOD signal. Electronic load The IC offers a 3V to 25V OUT programmable range. Procedure Switching frequency is adjustable from 220kHz to 2.2MHz, The MAX25431 EV kit is fully assembled and tested. Use which allows for small external components, reduced the following steps to verify board operation: output ripple, and guarantees no AM interference. The IC comes with a spread-spectrum frequency-modulation 1) Verify that all jumpers are in their default positions, as option designed to minimize EMI-radiated emissions and shown in Table 1. a SYNCOUT function that outputs 180 out-of-phase 2) Connect the positive and negative terminals of the clock. power supply to IN and GND test pads, respectively. 3) Set the power-supply voltage to 14V and 10A current Features limit. 6V to 36V Input Supply Range 4) Connect the positive terminal of the voltmeter to OUT Delivers Up to 16A Input Current and the negative terminal to GND2. Enable Input 5) Turn on the power supply. Frequency Synchronization Output Voltage-Monitoring PGOOD Output 6) Verify that OUT is approximately 12V. BIAS Voltage-Monitoring Test Point Additional Evaluation Fully Assembled and Tested 7) Connect the positive terminal of the electronic load to Proven PCB Layout OUT and the negative terminal to GND2. 8) Set the electronic load to 2A and turn on the load. 9) Verify output voltage on the voltmeter is 12V 2%. Ordering Information appears at end of data sheet. 10) With the load still on, slowly reduce the input voltage from 14V to 8V. Verify output voltage on the voltmeter is 12V 2%. 319-100558 Rev 0 7/20Evaluates: MAX25431 MAX25431 Evaluation Kit signal, pull up PGOOD to BIAS by installing a shunt on Detailed Description of Hardware the PGOOD jumper. The MAX25431 EV kit provides a proven layout for the MAX25431 buck-boost controller IC. The IC accepts input Evaluating Other Voltages voltage as high as 36V and can deliver high-load currents, The EV kit comes installed with the MAX25431ATGA/ with a 20A (max) input current in boost mode. The EV kit VY+ and is configured for 12V at a 420kHz switching OUT can handle an input-supply transient up to 40V. Various frequency set for 16A (max) input current in boost mode. test points are included for evaluation. The EV kit comes For evaluating other configurations, refer to the Design installed with a 3m current-sense resistor on the input Example table in the MAX25431 IC data sheet. Other IC (R1) and a 4m sense resistor on the output (R2). This options for spread spectrum/SYNCOUT can be installed sets the input current limit to 16.67A and the runaway as well. current limit to 18.75A. A higher current limit can be set by changing the sense resistors. An optional filter input EMC Performance (IN FILTER) is provided to test designs with an additional EV kit provides a proven layout that is compliant with input filter. The default EV kit comes with no filter installed, CISPR-25 requirements for EMC testing. The default EV so input terminal IN must be used. kit (12V , 420kHz configuration) requires no additional OUT filtering to meet the CISPR-25 EMC standards. The IC External Synchronization also comes with the spread-spectrum option, which can The IC operates in fixed-PWM (FPWM) with spread be ordered to improve EMC performance. spectrum enabled. The EV kit comes without the shunt installed on jumper, J3. The center pin of J3 can be used Specifications Summary to synchronize to an external clock. V (min): 6V IN When evaluating the MAX25431ATGB on this EV kit, the V (max): 36V IN SYNCOUT signal can be measured on the center pin of V : 12V OUT J3. The SKIP and FPWM silkscreen is used when evalu- f : 420kHz ating other Maxim Integrated Buck-Boost controllers. SW I (max): 5A OUT Output Monitoring (PGOOD) Input Current: 16.67A peak current The EV kit provides a power-good output test point Runaway Current: 18.75A peak current (PGOOD) to monitor the status of the buck output (OUT). PGOOD is an open-drain output and is high impedance SPS: On when the output voltage is in regulation. PGOOD is low FSYNC: SYNCIN impedance when the output voltage drops below 92% (typ) of its nominal regulated voltage. To obtain a logic Table 1. Default Jumper Settings JUMPER DEFAULT SHUNT POSITION FUNCTIONS J1 (EN) ON-Middle Buck-Boost enabled J4 (PGOOD PU) Installed PGOOD pulls up to VBIAS when OUT is in regulation MAX25431ATGA (Default): Apply the external clock input on center pin. J3 (SYNC) Not Installed MAX25431ATGB: The SYNCOUT signal can be measured on center pin Ordering Information PART TYPE MAX25431EVKIT 12V Output/420kHz EV kit Denotes RoHS-compliance. Maxim Integrated 2 www.maximintegrated.com