Evaluates: MAXM17505 in 5V MAXM17505 5V Output Output-Voltage Application Evaluation Kit General Description Features The MAXM17505 evaluation kit (EV kit) is a demonstration Highly Integrated Solution with Integrated Shield circuit of the MAXM17505 high-voltage, high-efficiency, Inductor current-mode scheme, synchronous step-down Wide 11V to 60V Input Range DC-DC switching power module. The EV kit is Preset 5V Output with a Fixed Resistor Divider on FB designed for 5V output and delivers up to 1.7A load (Feedback Pin) current from a wide input-voltage range of 11V to 60V. The EV kit switches at an optimal 500kHz switching Programmable Output-Voltage Feature (0.9V to 12V) frequency to allow the use of small component-sizes, Up to 1.7A Output Current helping to minimize solution-size while maintaining high- High 93.3% Efficiency (V = 12V, V = 5V at 0.74A) IN OUT performance. The EV kit provides a precision-enable 500kHz Switching Frequency input, an open-drain RESET output signal, and external frequency synchronization to provide a simple and reliable Enable/UVLO Input, Resistor-Programmable UVLO startup sequence and eliminate beat frequency between Threshold regulators. The EV kit also includes optional component Adjustable Soft-Start Time footprints to program different output voltages, an adjust- Selectable PWM, PFM, or DCM Mode able input undervoltage-lockout, and a soft-start time to control inrush current during startup. The MAXM17505 IC Open-Drain RESET Output data sheet provides a complete description of the part that External Frequency Synchronization should be read in conjunction with this data sheet prior to Overcurrent and Overtemperature Protection modifying the demo circuit. Low-Profile, Surface-Mount Components Lead(Pb)-Free and RoHS Compliant Ordering Information appears at end of data sheet. Fully Assembled and Tested 19-7607 Rev 0 4/15Evaluates: MAXM17505 in 5V MAXM17505 5V Output Evaluation Kit Output-Voltage Application ing frequency. On the bottom layer, additional footprints of Quick Start optional components are included to ease board modification Recommended Equipment for different input/output configurations. MAXM17505 EV kit Soft-Start Input (SS) 11V to 60V DC power supply (V ) IN The device utilizes an adjustable soft-start function to Dummy load capable of sinking 1.7A limit inrush current during startup. The soft-start time is Digital voltmeter (DVM) programmed by the value of the external capacitor from SS to GND (C1). The selected output capacitance (C ) SEL 100MHz dual-trace oscilloscope and the output voltage (V ) determine the minimum OUT Procedure value of C1, as shown by the following equation: The EV kit is fully assembled and tested. Follow the steps 3 C128 10 C V below to verify board operation. Caution: Do not turn on SEL OUT the power supply until all connections are completed. where C1 is in nF and C is in F SEL 1) Set the power supply at a voltage between 11V and The soft-start time (t ) is calculated by the equation SS 60V. Disable the power supply. below: 2) Connect the positive and negative terminals of the power supply to IN and PGND PCB pads, respectively. t = C1/ 5.55 SS 3) Connect the positive and negative terminals of the 1.7A load to OUT and PGND2 PCB pads, respectively, where t is in ms and C1 is in nF. SS and set the load to 0A. Programmable Undervoltage Lockout (UVLO) 4) Connect the DVM across the OUT PCB pad and the PGND2 PCB pad. The EV kit offers an adjustable input undervoltage-lockout 5) Verify that no shunts are installed across pin 1-2 on level by resistor dividers connected between the IN, EN/ jumper JU1 to enable UVLO (see Table 1 for details). UVLO, and GND pins. For normal operation, a shunt 6) Verify that a shunt is installed across JU3 to disable should not be installed across pins 1-2 on JU1 to enable the external synchronization (see Table 3 for details). the output through an internal pullup 3.3M resistor from 7) Verify that a shunt is installed across JU2 to enable the EN/UVLO pin to the IN pin. To disable the output, PWM mode (see Table 2 for details). install the shunt across pins 1-2 on JU1 to pull EN/UVLO 8) Enable the input power supply. pin to GND. See Table 1 for JU1 jumper setting details. 9) Verify the DVM displays 5V. The EV kit also provides an optional R3 PCB footprint to 10) Increase the load up to 1.7A to verify the DVM program a UVLO threshold voltage at which an input-voltage continues displaying 5V. level device turns on. The R3 resistor can be calculated by the following equation: Detailed Description of Hardware The EV kit is a proven circuit to demonstrate the high- 4009.5 R3 = voltage, high-efficiency, and compact solution-size of (V 1.215) INU the synchronous step-down DC-DC power module. The where V is the input voltage at which the device is output voltage is preset for 5V to operate from 11V to INU 60V, provideing up to 1.7A load current. The optimal required to turn on, and R3 unit is in k. frequency is set at 500kHz to maximize efficiency and Mode Selection (MODE) minimize component size. The EV kit includes jumpers JU1 Table 1. UVLO Enable/Disable to enable/disable UVLO of the device, JU2 to configure in PWM, PFM, or DCM mode in advantage of light-load Configuration (JU1) efficiency, and JU3 to enable/disable external clock SHUNT synchronize (SYNC). The RESET PCB pad is also EN PIN MAXM17505 OUTPUT POSITION available for monitoring output voltage regulation to enable/disable the application circuit of the load. The Installed Connected to GND Disable electrolytic capacitor (C8) is required only when the V Not installed* Connected to VIN Enable IN power supply is situated far from the MAXM17505 circuit. *Default position. When R4 is open, the device switches at 500kHz switch- Maxim Integrated 2 www.maximintegrated.com