Click here for production status of specific part numbers. Evaluates: MAXM15467 2.5V MAXM15467 2.5V Output Output-Voltage Application Evaluation Kit General Description Quick Start The MAXM15467 2.5V output evaluation kit (EV kit) Recommended Equipment provides a proven design to evaluate the MAXM15467 One 4.5V to 42V DC, 300mA power supply high-voltage, high-efficiency, synchronous step-down 0.5W resistive load with 300mA sink capacity DC-DC module. The EV kit is programmed to deliver 2.5V output for loads up to 300mA. The EV kit features Four digital multimeters (DMM) an adjustable input undervoltage lockout, selectable MAXM15467EVKIT mode, and open-drain RESET signal. The MAXM15467 data sheet provides a complete description of the module Equipment Setup and Test Procedure that should be read in conjunction with this EV kit data The EV kit is fully assembled and tested. Follow the steps sheet prior to modifying the demo circuit. For full module below to verify the board operation. features, benefits and parameters, refer to the MAXM15467 Caution: Do not turn on power supply until all data sheet. connections are completed. 1) Set the power supply at a voltage between 4.5V and Features 36V. Then, disable the power supply. Highly Integrated Solution 2) Connect the positive terminal of the power supply to Wide 4.5V to 36V Input Range the VIN PCB pad and the negative terminal to the Programmed 2.5V Output, Delivers Up To 300mA nearest GND PCB pad. Connect the positive termi- Output Current nal of the 300mA load to the VOUT PCB pad and the High 76.41% Efficiency negative terminal to the nearest GND PCB pad. (V = 24V, V = 2.5V at 150mA) IN OUT 3) Connect the DVM (DMM in voltage-measurement 550kHz Switching Frequency mode) across the VOUT PCB pad and the nearest GND PCB pad. ENABLE/UVLO Input, Resistor-Programmable UVLO Threshold 4) Verify that shunt is not installed on jumper J1 (see Table 1 for details). PFM Feature for Better Light-Load Efficiency 5) Turn on the DC power supply. Fixed Internal 3.75ms Soft-Start Time 6) Enable the load. RESET Output, with Pullup Resistor to V CC 7) Verify that the DVM displays 2.5V. Overcurrent and Overtemperature Protection (OCP and OTP) Low-Profile, Surface-Mount Components Ordering Information appears at end of data sheet. Proven PCB Layout Fully Assembled and Tested Complies with CISPR22(EN55022) Class B Conducted and Radiated Emissions 319-100336 Rev 0 3/19Evaluates: MAXM15467 2.5V MAXM15467 2.5V Output Evaluation Kit Output-Voltage Application Electro-Magnetic Interference (EMI) Detailed Description Compliance to conducted emissions (CE) standards The MAXM15467 EV kit is designed to demonstrate requires an EMI filter at the input of a switching power salient features of MAXM15467 power module. The EV kit converter. The EMI filter attenuates high-frequency includes an EN/UVLO PCB pad, and jumper J1, to enable currents drawn by the switching power converter, and the output at a desired input voltage. Jumper J2 allows limits the noise injected back into the input power source. selection of either PWM or PFM mode of operation based on light-load performance requirements. An additional Use of EMI filter components as shown in Figure 1 in RESET pad is available for monitoring if the converter conjunction with the schematic results in lower con- output voltage is in regulation. ducted emissions below CISPR22 Class B limits. The MAXM15467 EV kit PCB layout is also designed to limit Output Capacitor Selection radiated emissions from switching nodes of the power X7R ceramic output capacitors are preferred due to their converter resulting in radiated emissions below CISPR22 stability over temperature in industrial applications. The Class B limits. required output capacitor (C5) for 2.5V output is selected from Table 1 of the MAXM15467 data sheet as 10F/16V. Hot-Plug-In and Long Input Cables The MAXM15467 EV kit PCB provides an optional Adjusting Output Voltage electrolytic capacitor (C2, 4.7F/50V) to dampen input The MAXM15467 supports an adjustable output-voltage voltage peaks and oscillations that can arise during hot- range, from 0.9V to 6.3V, using a feedback resistive divid- plug-in and/or due to long input cables. This capacitor er from V to FB. Output voltage can be programmed OUT limits the peak voltage at the input of the MAXM15467 using the values given in Table 1 of the MAXM15467 data power module, when the EV kit is powered directly from a sheet. For 2.5V output, R3 is chosen as 133k, and R4 precharged capacitive source or an industrial backplane is chosen as 75k. PCB. Long input cables, between input power source and the EV kit circuit can cause input-voltage oscillations due Enable/Undervoltage-Lockout (EN/UVLO) Programming Table 1. UVLO Enable/Disable The MAXM15467 offers an adjustable input undervoltage- Configuration (J1) lockout feature. In this EV kit, for normal operation, leave jumper J1 open. When J1 is left open, the MAXM15467 MAXM15467 POSITION EN/UVLO PIN is enabled when the input voltage rises above 4.5V. To OUTPUT disable MAXM15467, install a jumper across pins 2-3 on Connected to the center Programmed to J1. See Table 1 for J1 settings. A potential divider formed Not node of resistor-divider startup at desired by R1 and R2 sets the input voltage (V ) at which the INU Installed* R1 and R2. input-voltage level. module is enabled. The value of resistor R1 is chosen to be 2.2M, and R2 is calculated using the following Enabled if V is IN 1-2 Connected to V IN equation: greater than V IN(MIN). R 1.215 2-3 Connected to GND Disabled 1 R = 2 ( V 1.215 ) *Default position INU where R1 and R2 are in k, For MAXM15467 to turn on at 4.5V input, the Resistor R2 VIN EMI VIN is calculated to be 825k. L 1 82H Input Capacitor Selection VIN EMI The input capacitor serves to reduce the current peaks C7 C8 C9 drawn from the input power supply and reduces switching 0.1F 0.47F 1F frequency ripple at the input. The input capacitance must be greater than or equal to the value given in Table 1 of MAXM15467 data sheet. Input capacitor C3 is chosen to be 1F/50V. Figure 1. EMI Filter Components Maxim Integrated 2 www.maximintegrated.com