Click here for production status of specific part numbers. Evaluates: MAX17546 MAX17546EVKITA Evaluation Kit 3.3V Output-Voltage Application General Description Quick Start The MAX17546 3.3V output evaluation kit (EV kit) provides Recommended Equipment a proven design to evaluate the MAX17546 high-voltage, MAX17546EVKITA high-efficiency, synchronous step-down DC-DC converter. 4.5V to 42V, 10A DC input power supply The EV kit is preset for a 3.3V output at load currents up to 5A and features a 450kHz switching frequency for Load capable of sinking 5A optimum efficiency and component size. The EV kit Digital voltmeter (DVM) features adjustable input undervoltage lockout, adjust- able soft-start, open-drain RESET signal, and external Procedure frequency synchronization. The EV kit is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn Features on power supply until all connections are completed. Operates from a 4.5V to 42V Input Supply 1) Set the power supply at a voltage between 4.5V and 3.3V Output Voltage 42V. Disable the power supply. Up to 5A Output Current 2) Connect the positive terminal of the power supply to the VIN PCB pad and the negative terminal to the 450kHz Switching Frequency nearest PGND PCB pad. Connect the positive terminal Enable/UVLO Input, Resistor-Programmable UVLO of the 5A load to the VOUT PCB pad and the negative Threshold terminal to the nearest PGND PCB pad. Adjustable Soft-Start Time 3) Connect the DVM across the VOUT PCB pad and MODE Pin to Select Among PWM, PFM, or DCM the nearest PGND PCB pad. Modes 4) Verify that the shunt is installed across pins 1-2 on Open-Drain RESET Output jumper JU1 (see Table 1 for details). External Frequency Synchronization 5) Select the shunt position on JU2 based on the intended mode of operation (see Table 2 for details). Overcurrent and Overtemperature Protection 6) Turn on the DC power supply. Proven PCB Layout 7) Enable the load. Fully Assembled and Tested 8) Verify that the DVM displays 3.3V Ordering Information appears at end of data sheet. 19-7694 Rev 2 4/18Evaluates: MAX17546 MAX17546EVKITA Evaluation Kit 3.3V Output-Voltage Application Mode/SYNC Selection (MODE) Detailed Description The devices MODE pin should be used to select among The MAX17546 EV kit provides a proven design to the PWM, PFM, or DCM modes of operation. The logic evaluate this high-voltage, high-efficiency, synchronous state of the MODE pin is latched when the V and step-down DC-DC converter. The EV kit is preset for a CC EN/UVLO voltages exceed the respective UVLO rising 3.3V output from a 4.5V to 42V input at load currents of thresholds and all internal voltages are ready to allow LX up to 5A and features a 450kHz switching frequency for switching. State changes on the MODE pin are ignored optimum efficiency and component size. during normal operation. Refer to the MAX17546 IC data The EV kit includes an EN/UVLO PCB pad and JU1 to sheet for more information on the PWM, PFM, and DCM enable the output at the desired input voltage. The SYNC modes of operation. PCB pad allows an external clock to synchronize the Table 2 shows EV kit jumper settings that can be used to device. JU2 allows the selection of a particular mode of configure the desired mode of operation. operation based on light-load performance requirements. An additional RESET PCB pad is available for monitoring The internal oscillator of the device can be synchronized whether the converter output is in regulation. to an external clock signal on the SYNC pin. The external synchronization clock frequency must be between 1.1f SW Soft-Start Input (SS) and 1.4f , where f is the frequency of operation SW SW The device utilizes an adjustable soft-start function to set by R5. The minimum external clock high pulse width limit inrush current during startup. The soft-start time is should be greater than 50ns and the minimum external adjusted by the value of the external capacitor from SS to clock low pulse width should be greater than 160ns. GND (C7). The selected output capacitance (C ) and SEL output voltage (V ) determine the minimum value of OUT Table 1. Regulator Enable (EN/UVLO) C7, as shown by the following equation: Description (JU1) -6 C7 28 x 10 x C x V SEL OUT SHUNT MAX17546 EN/UVLO PIN The soft-start time (t ) is related to C7 by the following SS POSITION OUTPUT equation: 12* Connected to VIN Enabled -6 t = C7/(5.55 x 10 ) SS Connected to the center Enabled, UVLO level Not in- For example, to program a 2.2ms soft-start time, C7 node of resistor-divider set through the R1 stalled should be 12nF. R1 and R2 and R2 resistors 23 Connected to SGND Disabled Regulator Enable/Undervoltage-Lockout Level (EN/UVLO) *Default position. The device offers an adjustable-input, undervoltage- lockout level. For normal operation, a shunt should be Table 2. MODE Description (JU2) installed across pins 1-2 on JU1. To disable the output, SHUNT MAX17546 install a shunt across pins 2-3 on JU1 and pull the EN/ MODE PIN POSITION MODE UVLO pin to GND. See Table 1 for JU1 settings. PFM mode of Set the voltage at which the device turns on with the resistive Not installed* Unconnected operation voltage-divider R1/R2 connected from VIN to SGND. PWM mode of Connect the center node of the divider to EN/UVLO. 12 Connected to SGND operation Choose R1 to be 3.32M and then calculate R2 as follows: DCM mode of 23 Connected to VCC operation R1x1.215 R2 = V 1.215 INU *Default position. where V is the voltage at which the device is required INU to turn on. Maxim Integrated 2 www.maximintegrated.com