MAX17548 Evaluation Kit Evaluates: MAX17548 General Description Quick Start The MAX17548 EV kit provides a proven design to evalu- Required Equipment ate the MAX17548 wide 4.5V to 42V input, dual-output, MAX17548 EV kit synchronous step-down DC-DC controller. The EV kit 4.5V to 42V, 15A DC power supply provides 5V/5A and 3.3V/10A at the outputs from a 6V to 42V input supply. The switching frequency of the EV kit Loads capable of sinking 5A and 10A is preset to 350kHz for optimal efficiency and component Two digital voltmeters (DVM) size. The EV kit features adjustable input undervoltage- lockout and soft-start time, selectable PWM/DCM modes, Procedure 180 out-of-phase/0 in-phase operation, current-limit The EV kit is fully assembled and tested. Follow the steps threshold, and independent open-drain PGOOD signals. below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. Features 1) Ensure that the DC power supply is disabled. Set the 6V to 42V Input Range power supply voltage to 24V. Output Rails: V : 5V/5A, V : 3.3V/10A OUT1 OUT2 2) Set one of the loads to 5A and the other to 10A. Disable 350kHz Switching Frequency the load in the case of an electronic load. Leave the load unconnected in the case of a resistor load and Independent Enable Inputs ensure that the resistor power rating is high enough Independent Adjustable Soft-Start Time to dissipate the output power. Configurable Tracking Operation 3) Connect the positive terminal of the power supply to Selectable PWM/DCM Modes of Operation the VIN connector and the negative terminal of the power supply to PGND connector, which is nearest Selectable 180 Out-of-Phase/0 In-Phase Operation to VIN connector. Selectable Current-Limit Threshold 4) Connect one digital voltmeter across VOUT1 con- Independent PGOOD Outputs nector and the nearest PGND connector with the Overcurrent, Overvoltage, and Overtemperature positive terminal of the DVM connected to VOUT1 Protection connector. Proven PCB Layout 5) Connect the other digital voltmeter across VOUT2 connector and the nearest PGND connector with the Fully Assembled and Tested positive terminal of the DVM connected to VOUT2 connector. 6) Verify the shunts on jumpers, as described in Table 1, Ordering Information appears at end of data sheet. to select default settings of the EV kit. 7) Turn on the DC power supply. 8) Verify that the digital voltmeters display the expected voltages (5V1% on VOUT1 and 3.3V1% on VOUT2). 9) Enable the electronic load (connect the load in the case of resistor load). 10) Verify that the voltmeters display the expected voltages (5V1% on V and 3.3V1% on V ). OUT1 OUT2 319-100066 Rev 0 8/17MAX17548 Evaluation Kit Evaluates: MAX17548 charges the capacitor at the SS pin, providing a linear Detailed Description of Hardware ramping voltage for output voltage reference. The soft- The EV kit provides a proven design to evaluate the start time of V and V are calculated based on OUT1 OUT2 device. The EV kit provides 5V/5A and 3.3V/10A at the the following equation: outputs from 6V to 42V input supply. The EV kit can also operate over the 4.5V to 42V range to provide only 3.3V 0.8V t C21 output by connecting a shunt of JU4 at the 2-3 position to SS OUT1 5A disable the 5V output. The EV kit is preset to operate at 350kHz for optimum efficiency and component size. The default soft-start time on the EV kit is approximately The EV kit provides set resistors R16, R17 and R18, R19 2.4ms. and jumpers JU4, JU5 to enable/disable the output at a Enable/Undervoltage-Lockout Level (EN ) desired input UVLO voltage. The DCM or PWM mode of operation can be selected using JU3. JU1 allows selection The devices two controllers may be independently shut of 180/0 phase-shift operation between the two controllers. down/enabled using the EN1 and EN2 pins. The EN JU2 allows the selection of three different current-limit pin can be programmed at 1.25V (typ) to detect the input thresholds for both controllers. Refer to Table 2 through undervoltage-lockout at a desired input voltage to enable/ Table 4 for additional jumper setting details. disable the corresponding controller with 50mV (typ) hysteresis. Connect a resistor-divider to EN from V to IN Configuring the Output Voltages (V , V ) OUT1 OUT2 GND to program the input undervoltage-lockout threshold The devices output voltages (V and V ) can be OUT1 OUT2 to turn on/off the corresponding controller. adjusted between 0.8V to 24V through sets of feedback For normal operation, the device is enabled whenever the resistor-dividers (R6, R7 and R26, R27) by the following input voltage is greater than 4.5V and JU4 and JU5 are formula: open. Set the voltage at which each controller turns on by placing a shunt across pins 1-2 on JU4 and JU5, and R6 R7 = adjust the resistor-divider formed by R16, R17 for control- V OUT1 ( 1) ler 1 and by R18, R19 for controller 2. Table 2 shows the 0.8 EV kits jumper settings for configuring the EN pin. Please refer to the MAX17548 IC data sheet to select R6 Select R17 (R19 for OUT2) below 10K and calculate the resistor values and change compensation components, as R16 (R18) based on the following equation: well as output capacitors, for new output voltage settings. Soft-Start (SS ) R17(V 1.25) INUVLO R16 = The device offers an SS pin used to adjust the soft-start 1.25 time to limit inrush current during startup. Soft-start times Where V is the input voltage at which the control- INUVLO are controlled by the values of C21 and C30 for V OUT1 ler is required to turn on. and V , respectively. An internal 5A current source OUT2 Table 1. Default Setting of MAX17548 EV kit JUMPER SHUNT POSITION FUNCTION JU1 Unconnected Configure output 1 and output 2 180 out-of-phase operation JU2 1-2 Select 75mV current-limit threshold JU3 1-2 Select the PWM mode of operation JU4 Unconnected Enable control 1 JU5 Unconnected Enable control 2 Maxim Integrated 2 www.maximintegrated.com =