MAX17541G in 3.3V MAX17541G 3.3V Output Output-Voltage Application Evaluation Kit General Description Quick Start The MAX17541G 3.3V EV kit provides a proven design to Recommended Equipment evaluate the MAX17541G 3.3V high-efficiency, high-voltage, MAX17541G 3.3V EV kit synchronous step-down DC-DC converter. The EV kit 5V to 42V, 2A DC input power supply generates 3.3V at load currents up to 500mA from a 5V to 42V input supply. The EV kit features a 600kHz fixed Load capable of sinking 500mA switching frequency for optimum efficiency and component Digital voltmeter (DVM) size. The EV kit features a forced-PWM control scheme that Function generator provides constant switching-frequency operation at all load and line conditions. 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 5V to 42V Input Supply on power supply until all connections are completed. 3.3V Output Voltage 1) Set the power supply at a voltage between 5V and 500mA Output Current 42V. Disable the power supply. 600kHz Switching Frequency 2) Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the nearest Enable/UVLO Input PGND PCB pad. Connect the positive terminal of the Resistor-Programmable UVLO Threshold 500mA load to the VOUT PCB pad and the negative Open-Drain RESET Output terminal to the nearest PGND PCB pad. Overcurrent and Overtemperature Protection 3) Connect the DVM across the VOUT PCB pad and the nearest PGND PCB pad. Proven PCB Layout 4) Turn on the DC power supply. Fully Assembled and Tested 5) Enable the load. 6) Verify that the DVM displays 3.3V. Ordering Information appears at end of data sheet. To turn-on/off the part from EN/UVLO, follow the steps below: 1) Connect the power supply to the EV kit and turn on the power supply. Set the power supply at a voltage between 5V and 42V. 2) Connect the function generator output to the EN/UVLO test loop. 3) EN/UVLO rising threshold is 1.24V and falling threshold is 1.11V. Make sure that the voltage-high and voltage- low levels of the function generator output are greater than 1.24V and less than 1.11V, respectively. 4) While powering down the EV kit, first disconnect the function generator output from the EN/UVLO test loop and then turn off the DC power supply. 19-7722 Rev 0 7/15MAX17541G in 3.3V MAX17541G 3.3V Output Evaluation Kit Output-Voltage Application Regulator Enable/Undervoltage-Lockout Detailed Description of Hardware Level (EN/UVLO) The MAX17541G 3.3V EV kit provides a proven design The device features an EN/UVLO input. For normal to evaluate the MAX17541G 3.3V high-efficiency, high- operation, no shunts should be installed across pins 1-2 voltage, synchronous step-down DC-DC converter. The or 2-3 on jumper JU1. To disable the output, install a shunt EV kit generates 3.3V at load currents up to 500mA across pins 2-3 on JU1 and the EN/UVLO pin is pulled to from a 5V to 42V input supply. The EV kit features a GND. See Table 1 for JU1 settings. 600kHz fixed switching frequency for optimum efficiency and component size. The EV kit features a forced- Setting the Undervoltage-Lockout Level PWM control scheme that provides constant switching- The device offers an adjustable input undervoltage- frequency operation at all load and line conditions. lockout level. Set the voltage at which the device turns The EV kit includes an EN/UVLO PCB pad to enable on with a resistive voltage-divider connected from VIN control of the converter output. An additional RESET to GND (see Figure 1). Connect the center node of the PCB pad is available for monitoring the open-drain logic divider to EN/UVLO. output. The VCC PCB pad helps measure the internal Choose R1 to be 3.3M and then calculate R2 as follows: LDO voltage. R1 1.218 Soft-Start Input (SS) R2 = (V 1.218) INU The device utilizes an adjustable soft-start function to limit inrush current during startup. The soft-start time is where V is the voltage at which the device is required adjusted by the value of C3, the external capacitor from INU to turn on. Ensure that V is higher than 0.8 x V . SS to GND. To adjust the soft-start time, determine C3 INU OUT using the following formula: Adjusting the Output Voltage C3 = 5.55 x t SS The device offers an adjustable output voltage. Set the where t is the required soft-start time in milliseconds output voltage with a resistive voltage-divider connected SS and C3 is in nanofarads. from the positive terminal of the output capacitor (V ) OUT to GND (see schematic attached to PDF). Connect the center node of the voltage-divider to FB. To choose the values of R4 and R5, select the parallel combination of R4 and R5, with R less than 15k. Once P R is selected, calculate R4 as follows: P RV P OUT R4 = 0.9 Calculate R5 as follows: R4 0.9 R5 = (V 0.9) OUT Table 1. Regulator Enable (EN/UVLO) Jumper JU1 Settings SHUNT POSITION EV/UVLO PIN MAX17541G 3.3V OUTPUT Connected to the center node of resistor-divider Enabled, UVLO level set through the R1 and R2 Not installed* R1 and R2 resistor-divider 2-3 Connected to GND Disabled *Default position. Maxim Integrated 2 www.maximintegrated.com