Click here for production status of specific part numbers. Evaluates: MAXM15464 5V MAXM15464 5V Output Output-Voltage Application Evaluation Kit General Description Quick Start The MAXM15464 5V output evaluation kit (EV kit) pro- Recommended Equipment vides a proven design to evaluate the MAXM15464 high- One 4.5V to 42V DC, 300mA power supply voltage, high-efficiency, synchronous step-down DC-DC 1.5W resistive load with 300mA sink capacity module. The EV kit is programmed to deliver 5V output for loads up to 300mA. The EV kit features an adjust- Four digital multimeters (DMM) able input undervoltage lockout, selectable mode, and MAXM15464EVKIT open-drain RESET signal. The MAXM15464 data sheet provides a complete description of the module that should Equipment Setup and Test Procedure be read in conjunction with this EV kit data sheet prior to The EV kit is fully assembled and tested. Follow the steps modifying the demo circuit. For full module features, ben- below to verify the board operation. efits and parameters, refer to the MAXM15464 data sheet. Caution: Do not turn on power supply until all connections are completed. Features 1) Set the power supply at a voltage between 4.5V and Highly Integrated Solution 42V. Then, disable the power supply. Wide 12V to 42V Input Range 2) Connect the positive terminal of the power supply to Fixed 5V Output, Delivers Up To 300mA Output the VIN PCB pad and the negative terminal to the Current nearest GND PCB pad. Connect the positive termi- High 84.7% Efficiency nal of the 300mA load to the VOUT PCB pad and the (V = 24V, V = 5V at 150mA) negative terminal to the nearest GND PCB pad. IN OUT 500kHz Switching Frequency 3) Connect the DVM (DMM in voltage-measurement mode) across the VOUT PCB pad and the nearest ENABLE/UVLO Input, Resistor-Programmable GND PCB pad. UVLO Threshold 4) Verify that shunt is not installed on jumper J1 PFM Feature for Better Light-Load Efficiency (see Table 1 for details). Fixed Internal 4.1ms Soft-Start Time 5) Turn on the DC power supply. RESET Output, with Pullup Resistor to V CC 6) Enable the load. Overcurrent and Overtemperature Protection 7) Verify that the DVM displays 5V. (OCP and OTP) Low-Profile, Surface-Mount Components Proven PCB Layout Ordering Information appears at end of data sheet. Fully Assembled and Tested Complies with CISPR22 (EN55022) Class B Conducted and Radiated Emissions 319-100297 Rev 0 1/19MAXM15464 5V Output Evaluates: MAXM15464 5V Evaluation Kit Output-Voltage Application rents drawn by the switching power converter, and limits Detailed Description the noise injected back into the input power source. The MAXM15464 EV kit is designed to demonstrate Use of EMI filter components as shown in Figure 1 in salient features of MAXM15464 power module. The EV kit includes an EN/UVLO PCB pad, and jumper J1, to enable conjunction with the schematic results in lower con- ducted emissions below CISPR22 Class B limits. The the output at a desired input voltage. Jumper J2 allows selection of either PWM or PFM mode of operation based MAXM15464 5V EV Kit PCB Layout Diagrams is also designed to limit radiated emissions from switching nodes on light-load performance requirements. An additional RESET pad is available for monitoring if the converter of the power converter, resulting in radiated emissions below CISPR22 Class B limits. output voltage is in regulation. Output Capacitor Selection Hot-Plug-In and Long Input Cables The MAXM15464 EV kit PCB provides an optional X7R ceramic output capacitors are preferred due to their electrolytic capacitor (C2, 4.7F/50V) to dampen input stability over temperature in industrial applications. The voltage peaks and oscillations that can arise during hot- required output capacitor (C5) for 5V output is selected plug-in and/or due to long input cables. This capacitor from Table 1 of the MAXM15464 data sheet as 10F/6.3V. limits the peak voltage at the input of the MAXM15464 Fixed Output Voltage power module, when the EV kit is powered directly from a The MAXM15464 is a fixed 5V output module. Connect precharged capacitive source or an industrial backplane FB of MAXM15464 directly to V for feedback control. OUT PCB. Long input cables, between input power source and the EV kit circuit can cause input-voltage oscillations due Enable/Undervoltage-Lockout (EN/UVLO) to the inductance of the cables. The equivalent series Programming resistance (ESR) of the electrolytic capacitor helps damp The MAXM15464 offers an adjustable input undervoltage- out the oscillations caused by long input cables. Further, lockout feature. In this EV kit, for normal operation, leave capacitor C1 (0.1F/50V), placed near the input of the jumper J1 open. When J1 is left open, the MAXM15464 board, helps in attenuating high frequency noise. is enabled when the input voltage rises above 12V. To Mode of Operation disable MAXM15464, install a jumper across pins 2-3 on J1. See Table 1 for J1 settings. A potential divider formed The MAXM15464 features PFM mode of operation to by R1 and R2 sets the input voltage (V ) at which the INU increase the efficiency at light-load condition. If the MODE module is enabled. The value of resistor R1 is chosen pin is left unconnected during powerup, the module to be 2.2M, and R2 is calculated using the following operates in PFM mode at light loads. If the MODE pin is equation: connected to GND during power-up, the part operates in constant-frequency PWM mode at all loads. See Table 2 R 1.215 1 for J2 settings. R = 2 ( V 1.215 ) INU Internal LDO where R1 and R2 are in k, An internal regulator provides a 5V nominal supply to For MAXM15464 to turn on at 12V input, the Resistor R2 power the internal functions of the module. The output of is calculated to be 249k. the linear regulator (V ) should be bypassed with a 1F CC capacitor C4 to GND. Input Capacitor Selection The input capacitor serves to reduce the current peaks VIN EMI VIN drawn from the input power supply and reduces switching frequency ripple at the input. The input capacitance must L1 VIN EMI be greater than or equal to the value given in Table 1 of 82H MAXM15464 data sheet. Input capacitor C3 is chosen to C9 C8 C7 be 1F/50V. 0.68F 1F 0.1F Electromagnetic Interference (EMI) Compliance to conducted emissions (CE) standards requires an EMI filter at the input of a switching power Figure 1. EMI Filter Components converter. The EMI filter attenuates high-frequency cur- Maxim Integrated 2 www.maximintegrated.com