MAX17575 5V Output Evaluation Kit Evaluates: MAX17575 in 5V Output-Voltage Application General Description Quick Start The MAX17575 5V output evaluation kit (EV kit) provides Recommended Equipment a proven design to evaluate the MAX17575 high-voltage, MAX17575 5V output EV kit high-efficiency, synchronous step-down DC-DC converter. 6V to 60V, 2A DC input power supply The EV kit is preset for 5V output at load currents up to 1.5A and features a 500kHz switching frequency for optimum Load capable of sinking 1.5A efficiency and component size. The EV kit features adjustable Digital voltmeter (DVM) input undervoltage-lockout, adjustable soft-start, open- drain RESET signal, and external frequency synchronization. Procedure The EV kit is fully assembled and tested. Follow the steps Features below to verify the board operation. Caution: Do not turn Operates From a 6V to 60V Input Supply on power supply until all connections are completed. 5V Output Voltage 1) Set the power supply at a voltage between 6V and Up to 1.5A Output Current 60V. Disable the power supply. 500kHz Switching Frequency 2) Connect the positive terminal of the power supply Enable/UVLO Input, Resistor-Programmable UVLO to the V PCB pad and the negative terminal to the IN Threshold nearest PGND PCB pad. Connect the positive terminal Adjustable Soft-Start Time of the 1.5A load to the V PCB pad and the negative OUT terminal to the nearest PGND PCB pad. Open-Drain RESET Output External Frequency Synchronization 3) Connect the DVM across the V PCB pad and OUT the nearest PGND PCB pad. Overcurrent and Overtemperature Protection Proven PCB Layout 4) Verify that shunts are installed across pins 1-2 on jumper JU1 (see Table 1 for details). Fully Assembled and Tested 5) Turn on the DC power supply. 6) Enable the load. Ordering Information appears at end of data sheet. 7) Verify that the DVM displays 5V 19-8765 Rev 1 6/17MAX17575 5V Output Evaluation Kit Evaluates: MAX17575 in 5V Output-Voltage Application Connect the center node of the divider to EN/UVLO. Choose Detailed Description of Hardware R1 to be 3.3M and then calculate R2 as follows: The MAX17575 5V output EV kit provides a proven design to evaluate the MAX17575 high-voltage, high 1.215 R1 efficiency, synchronous step-down DC-DC converter. R2 = (V 1.215) INU The EV kit is preset for 5V output from 6V to 60V input at load currents up to 1.5A and features a 500kHz switching where V is the voltage at which the device is required INU frequency for optimum efficiency and component size. to turn on. Ensure that V is higher than 0.8 x V . INU OUT The EV kit includes an EN/UVLO PCB pad and jumper If the EN/UVLO pin is driven from an external signal source, JU1 to enable the output at a desired input voltage. An a series resistance of minimum 1k is recommended to be additional RESET PCB pad is available for monitoring placed between the signal source output and the EN/UVLO whether the converter output is in regulation. pin, to reduce voltage ringing on the line. Soft-Start Capacitor Selection Adjusting Output Voltage The device implements adjustable soft-start operation to Set the output voltage with a resistive voltage-divider connected reduce inrush current. A capacitor connected from the SS from the positive terminal of the output capacitor (V ) pin to GND programs the soft-start time. The selected OUT to SGND (Figure 2). Connect the center node of the divid- output capacitance (C ) and the output voltage (V ) SEL OUT er to the FB pin. Use the following procedure to choose determine the minimum required soft-start capacitor as the resistive voltage-divider values: follows: Calculate resistor R3 from the output to the FB pin as 6 C 56 10 C V SS SEL OUT follows: The soft-start time (t ) is related to the capacitor SS 1850 R3 = connected at SS (C ) by the following equation: SS C OUT SEL C SS t = Where C (in F) is the actual derated value of SS OUT SEL 6 5.55 10 the output capacitance used and R3 is in k. The minimum allowable value of R3 is (5.6 x V ), where R3 is in k. OUT For example, to program a 2ms soft-start time, a 12nF If the value of R3 calculated using the above equation capacitor should be connected from the SS pin to GND. is less than (5.6 x V ), increase the value of R3 to at OUT least (5.6 x V ). Setting the Undervoltage-Lockout Level OUT The device offers an adjustable input undervoltage-lockout R3 0.9 level. Set the voltage at which the device turns on with a resis- R4 = (V 0.9) tive voltage-divider connected from V to SGND (Figure 1). OUT IN R4 is in k. Table 1. Regulator Enable (EN/UVLO) Description (JU1) SHUNT POSITION EN/UVLO PIN MAX17575 OUTPUT 1-2* Connected to VIN Enabled Connected to the center node of Enabled, UVLO level set through Not installed resistor-divider R1 and R2 the R1 and R2 resistors 2-3 Connected to SGND Disabled Maxim Integrated 2 www.maximintegrated.com