Click here for production status of specific part numbers. Evaluates: MAXM15465 3.3V MAXM15465 3.3V Output Output-Voltage Application Evaluation Kit General Description Quick Start The MAXM15465 3.3V output evaluation kit (EV kit) Recommended Equipment provides a proven design to evaluate the MAXM15465 One 4.5V to 42V DC, 300mA power supply high-voltage, high-efficiency, synchronous step-down 1W resistive load with 300mA sink capacity DC-DC module. The EV kit is programmed to deliver 3.3V output for loads up to 300mA. The EV kit features Four digital multimeters (DMM) an adjustable input undervoltage lockout, selectable MAXM15465EVKIT mode, and open-drain RESET signal. The MAXM15465 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 MAXM15465 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 42V. Then, disable the power supply. Highly Integrated Solution 2) Connect the positive terminal of the power supply to Wide 5.5V to 42V Input Range the VIN PCB pad and the negative terminal to the Fixed 3.3V 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 80.43% Efficiency negative terminal to the nearest GND PCB pad. (V = 24V, V = 3.3V 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 3.3V. Overcurrent and Overtemperature Protection (OCP and OTP) Ordering Information appears at end of data sheet. Low-Profile, Surface-Mount Components Proven PCB Layout Fully Assembled and Tested Complies with CISPR22(EN55022) Class B Conducted and Radiated Emissions 319-100330 Rev 0 3/19Evaluates: MAXM15465 3.3V MAXM15465 3.3V Output Evaluation Kit Output-Voltage Application Input Capacitor Selection Detailed Description The input capacitor serves to reduce the current peaks The MAXM15465 EV kit is designed to demonstrate drawn from the input power supply and reduces switching salient features of MAXM15465 power module. The EV kit frequency ripple at the input. The input capacitance must includes an EN/UVLO PCB pad, and jumper J1, to enable be greater than or equal to the value given in Table 1 of the output at a desired input voltage. Jumper J2 allows MAXM15465 data sheet. Input capacitor C3 is chosen to selection of either PWM or PFM mode of operation based be 1F/50V. on light-load performance requirements. An additional RESET pad is available for monitoring if the converter Electro-Magnetic Interference (EMI) output voltage is in regulation. Compliance to conducted emissions (CE) standards Output Capacitor Selection requires an EMI filter at the input of a switching power converter. The EMI filter attenuates high-frequency cur- X7R ceramic output capacitors are preferred due to their rents drawn by the switching power converter, and limits stability over temperature in industrial applications. The the noise injected back into the input power source. required output capacitor (C5) for 3.3V output is selected from Table 1 of the MAXM15465 data sheet as 10F/16. Use of EMI filter components as shown in Figure 1 in conjunction with the schematic results in lower con- Fixed Output Voltage ducted emissions, below CISPR22 Class B limits. The The MAXM15465 is a fixed 3.3V output module. Connect MAXM15465 EV kit PCB layout is also designed to limit FB of MAXM15465 directly to V for feedback control. OUT radiated emissions from switching nodes of the power converter, resulting in radiated emissions below CISPR22 Enable/Undervoltage-Lockout (EN/UVLO) Class B limits. Programming The MAXM15465 offers an adjustable input undervoltage- Hot-Plug-In and Long Input Cables lockout feature. In this EV kit, for normal operation, leave The MAXM15465 EV kit PCB provides an optional jumper J1 open. When J1 is left open, the MAXM15465 is electrolytic capacitor (C2, 4.7F/50V) to dampen input enabled when the input voltage rises above 5.4V. To dis- voltage peaks and oscillations that can arise during hot- able MAXM15465, install a jumper across pins 2-3 on J1. plug-in and/or due to long input cables. This capacitor See Table 1 for J1 settings. A potential divider formed by limits the peak voltage at the input of the MAXM15465 R1 and R2 sets the input voltage (V ) at which the mod- INU power module, when the EV kit is powered directly from a ule is enabled. The value of resistor R1 is chosen to be precharged capacitive source or an industrial backplane 2.2M, and R2 is calculated using the following equation: PCB. Long input cables, between input power source and the EV kit circuit can cause input-voltage oscillations due R 1.215 1 R = 2 to the inductance of the cables. The equivalent series ( V 1.215 ) INU resistance (ESR) of the electrolytic capacitor helps damp out the oscillations caused by long input cables. Further, where R1 and R2 are in k, capacitor C1 (0.1F/50V), placed near the input of the For MAXM15465 to turn on at 5.4V input, the Resistor R2 board, helps in attenuating high frequency noise. is calculated to be 634k. Table 1. UVLO Enable/Disable Configuration (J1) POSITION EN/UVLO PIN MAXM15465 OUTPUT Connected to the center node of resistor-divider Programmed to startup at desired input-voltage Not Installed* R1 and R2. level. 1-2 Connected to V Enabled if V is greater than V IN IN IN(MIN). 2-3 Connected to GND Disabled *Default position Maxim Integrated 2 www.maximintegrated.com