Click here for production status of specific part numbers. Evaluates: MAX20059 MAX20059 Evaluation Kit General Description Quick Start The MAX20059 EV kit is a proven design to evaluate the Required Equipment MAX20059 high-efficiency, high-voltage, synchronous MAX20059 EV kit step-down DC-DC converter IC in a TDFN package. The Adjustable DC power supply EV kit is optimized to generate a 5V output at load cur- rents up to 1A from a 48V input supply, and can be recon- Digital multimeter (DMM) figured to meet other system requirements. The EV kit Electronic load features a 400kHz switching frequency. The EV kit can be used to monitor the ICs features, such as adjustable input Procedure undervoltage lockout, adjustable soft-start, adjustable The EV kit is fully assembled and tested. Follow the steps switching frequency, adjustable current limit, open-drain below to verify board operation: RESET signal, and external frequency synchronization. 1) Verify that all jumpers are positioned to their default settings (Table 1). Benefits and Features 2) Preset the power supply to 48V. Disable the power Operates from 6.5V to 72V at 48V Nominal Input supply. Meets Stringent OEM Module Power Consumption 3) Preset the electronic load to 500mA. Disable the and Performance Specifications electronic load. 4) Connect the positive lead of the power supply to the 5V Output Voltage at 400kHz Switching Frequency VIN PCB pad on the EV kit. Up to 1A Output Current with Adjustable Peak- 5) Connect the negative lead to the neighboring PGND Current Limit PCB pad. Jumpers for Quickly Adjusting Peak-Current Limit 6) Connect the positive terminal of the electronic load and Mode Selection to the VOUT PCB pad. 7) Connect the negative lead to the neighboring Auxiliary Bootstrap LDO to Improve Efficiency PGND2 PCB pad. Adjustable Soft-Start Time with External Capacitor 8) Enable the DC power supply. Optimized Application Layout and Components for 9) Using the DMM, verify that voltage across the VOUT Quick Design Implementation and PGND2 PCB pads is 5V. 10) Turn on the electronic load. Proven PCB Layout 11) Verify that the voltage across the VOUT and PGND Fully Assembled and Tested PCB pads is still close to 5V after load regulation. 12) Turn off the electronic load. 13) Turn off the power supply. Ordering Information appears at end of data sheet. 319-100265 Rev 0 10/18Evaluates: MAX20059 MAX20059 Evaluation Kit Regulator Enable/Undervoltage-Lockout Detailed Description Level (EN/UVLO) The MAX20059 5V output EV kit provides a proven design The device offers an adjustable-input undervoltage-lock- to evaluate the MAX20059 high-efficiency, high-voltage, out level. For always-on operation, no shunt should be synchronous step-down DC-DC converter IC. The EV kit installed across JU1. To disable the output, install a shunt generates 5V at load currents up to 1A from a 6.5V to across pins 2-3 on JU1 and the EN/UVLO pin is pulled to 72V input supply. The EV kit features a 400kHz switching GND. See Table 1 for JU1 default settings. frequency for optimum efficiency and component size. The EV kit includes an EN/UVLO PCB pad and jumper Set the voltage at which each converter turns on with a JU1 to enable the output at a desired input voltage. The resistive voltage-divider connected from V to SGND. IN RT/SYNC IN PCB pad allows an external clock to syn- Connect the center node of the divider to the EN/UVLO chronize the device while the IC is set to FPWM through pin. Choose R1 as follows: jumper JU4 or JU5. A RESETB PCB pad is available for R1 110000 x V INU monitoring when the converter output is in regulation. where V is the input voltage at which the IC is required INU Soft-Start Input (SS) to turn on, and R1 is measured in ohms. Calculate the The IC implements adjustable soft-start operation to value of R2 as follows: reduce inrush current and to minimize output-voltage 1.215 R1 overshoot during startup. A capacitor connected from the R2 = V 1.215+ (2.5AR1) INU SS pin to SGND (C6 on the EV kit) programs the soft-start time for the corresponding output voltage. The selected Current Limit and Mode-of output capacitance (C ) and the output voltage (V ) SEL OUT Operation Selection determine the minimum required soft-start capacitor as follows: Table 2 lists the values of the resistor R5 to program PWM or PFM modes of operation and 1.6A or 1.14A peak cur- -6 C 30 x 10 x C x V SS SEL OUT rent limits. The soft-start time (t ) is related to the capacitor con- SS On the EV kit, jumpers JU2JU5 are connected to each nected at SS (C ) by the following equation: SS of the above values for easy evaluation of each mode C and peak current limit. The mode of operation cannot be SS t = SS 6 changed on-the-fly after power-up until the power supply 6.25 10 is reset or the IC has been disabled. For example, to program a 2ms soft-start time, a 12nF capacitor should be connected from the SS pin to SGND. Table 2. R Resistor vs. Modes of Table 1. Default Jumper Settings ILIM Operation and Peak Current Limit DEFAULT SHUNT JUMPER FUNCTION POSITION R MODE OF PEAK CURRENT LIMIT ILIM Installed, across (k) OPERATION (A) JU1 Enable for VOUT pins 2-3 OPEN PFM 1.6 JU2 Open PFM/1.6A peak ILIM 422 PFM 1.14 JU3 Open PFM/1.14A peak ILIM 243 PWM 1.6 JU4 Installed FPWM/1.6A peak ILIM 121 PWM 1.14 JU5 Open FPWM/1.14A peak ILIM Note: Only 1 jumper between JU2-5 should be installed. For 3-pin connectors, pin 1 is denoted by a silkscreen circle. Maxim Integrated 2 www.maximintegrated.com