Evaluates: MAX17524 Dual-Output MAX17524 Dual Output Voltage 3.3V and 5V Application Evaluation Kit General Description Quick Start The MAX17524 evaluation kit (EV kit) provides a proven Recommended Equipment design to evaluate the MAX17524 high-efficiency, high- MAX17524EVKIT voltage, synchronous step-down dual DC-DC converter. 6.5V to 60V, 5A DC-input power supply The EV kit is preset to generate 3.3V and 5V output volt- ages, at load currents up to 3A per converter and features Two loads capable of sinking 3A a 450kHz switching frequency for optimum efficiency and Two digital voltmeters (DVM) component size. The EV kit features adjustable input undervoltage lockout, adjustable soft-start, open-drain Equipment Setup and Test Procedure RESET signal, and external frequency synchronization. The EV kit is fully assembled and tested. Follow the steps below to verify the board operation. Caution: Do not turn Features on power supply until all connections are completed. Operates from a 6.5V to 60V Input Supply 1) Set the power supply at a voltage between 6.5V and Dual Output Voltage: 3.3V and 5V 60V. Disable the power supply. Up to 3A Output Current Per Converter 2) Connect the positive terminal of the power supply to the VIN1 PCB pad and the negative terminal to 450kHz Switching Frequency the nearest PGND1 PCB pad. Connect the positive Enable/UVLO Input, Resistor-Programmable terminal of the 3A load to the VOUT1 PCB pad and UVLO Threshold the negative terminal to the nearest PGND1 PCB pad. MODE/SYNC Pin to Select Among PWM, PFM, Connect the positive terminal of the other 3A load to or DCM Modes the VOUT2 PCB pad and the negative terminal to the nearest PGND2 PCB pad. Open-Drain RESET Output 3) Connect the DVMs across the VOUT1 PCB pad and External Frequency Synchronization the nearest PGND1 PCB pad, and across the VOUT2 Overcurrent and Overtemperature Protection PCB pad and the nearest PGND2 PCB pad. Proven PCB Layout 4) Verify that shunts are installed across pins 1-2 on Fully Assembled and Tested jumper JU4 and pins 1-2 on JU5 (see Table 1 and 2). 5) Select the shunt position on jumper JU1 and JU2 Ordering Information appears at end of data sheet. according to the intended mode of operation (see Table 3 and 4). 6) Verify that the shunt is connected across pins 1-2 on jumper JU3 (see Table 5 for details). 7) Turn on the DC power supply. 8) Enable the loads. 9) Verify that the DVMs display 3.3V and 5V. 319-100117 Rev 0 12/17Evaluates: MAX17524 Dual-Output MAX17524 Dual Output Evaluation Kit Voltage 3.3V and 5V Application Setting the Input Enable/Undervoltage- Detailed Description Lockout Level (EN/UVLO1, EN/UVLO2) The MAX17524 EV kit provides a proven design to The device offers an adjustable input undervoltage- evaluate the MAX17524 high-efficiency, high-voltage, lockout level for each output. Set the voltage at which synchronous step-down Dual DC-DC converter. The EV each converter turns on with a resistive voltage-divider kit generates a fixed 3.3V and 5V, at load currents up to connected from V to SGND. Connect the center node 3A per channel, from a 6.5V to 60V input supply. The EV IN of the divider to EN/UVLO pins as shown in Figure 1. kit features a 450kHz fixed switching frequency for opti- mum efficiency and component size. Choose R to be 3.3M, and then calculate R TOP BOT as: This EV kit includes an EN/UVLO PCB pad and JU4, JU5 to enable the two outputs at a desired input voltage. The R 1.216 TOP MODE/SYNC1 PCB pad and JU1, and MODE/SYNC2 R = BOT V 1.216 INU PCB pad and JU2 allow an external clock to synchronize the respective channels. The EV kit features individual Where V is the input voltage at which the desired INU mode-of-operation selector pins, adjustable input under- converter is required to turn on. Install a shunt across pins voltage lockout (EN/UVLO) pins, adjustable soft-start 1-2 on JU4 and JU5 to enable the EV kit outputs and for pins, open-drain RESET signals for each output channel. always on operation. See Table 1 and Table 2 for proper jumper settings. Soft-Start Input (SS) The device implements adjustable soft-start operation Table 1. Regulator Enable (EN/UVLO1) for each output to reduce inrush current. Capacitors Description (JU4) connected from the SS pins to SGND (C ) programs SS the soft-start time for the corresponding output voltage. SHUNT EN/UVLO1 MAX17524 The selected output capacitance (C ) and the output POSITION PIN OUTPUT1 SEL voltage (V ) determine the minimum required soft-start OUT 1-2* Connected to V Enabled IN1 capacitor as follows: Connected to the center Enabled, UVLO level -6 C 28 10 C V SS SEL OUT Not node of resistor-divider set through the installed The soft-start time (t ) is related to the capacitor SS R1 and R2 R1 and R2 resistors connected at SS (C ) by the following Equation: SS 2-3 Connected to SGND Disabled C SS t = SS 6 (5.55 10 ) Table 2. Regulator Enable (EN/UVLO2) Description (JU5) For example, to program a 1ms soft-start time on one channel, a 5.6nF capacitor should be connected from the SHUNT EN/UVLO2 MAX17524 corresponding SS pin to SGND. POSITION PIN OUTPUT2 1-2* Connected to V Enabled IN2 Connected to the center Enabled, UVLO V V IN1 IN2 IN1 IN2 Not installed node of resistor-divider level set through the R3 and R4 R3 and R4 resistors R TOP2 R TOP1 MAX17524 2-3 Connected to SGND Disabled EN/UVLO2 EN/UVLO1 R R BOT1 BOT2 SGND SGND Figure 1. Setting the Input Undervoltage Lockout Maxim Integrated 2 www.maximintegrated.com