Click here for production status of specific part numbers. Evaluates: MAXM15068 12V MAXM15068 12V Output Output-Voltage Application Evaluation Kit General Description Quick Start The MAXM15068 12V output evaluation kit (EV kit) Recommended Equipment provides a proven design to evaluate the MAXM15068 One 15.5V to 60V DC, 200mA power supply high-voltage, high-efficiency, synchronous step-down 2.4W resistive load with 200mA sink capacity DC-DC module. The EV kit is programmed to deliver 12V output for loads up to 200mA. The EV kit features an Four digital multimeters (DMM) adjustable input undervoltage lockout, selectable mode, MAXM15068EVKIT and open-drain RESET signal. The MAXM15068 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 MAXM15068 Caution: Do not turn on power supply until all data sheet. connections are completed. 1) Set the power supply at a voltage between 15.5V and Features 60V. Then, disable the power supply. Highly Integrated Solution 2) Connect the positive terminal of the power supply to Wide 15.5V to 60V Input Range the VIN PCB pad and the negative terminal to the Programmed 12V Output, Delivers Up To 200mA nearest GND PCB pad. Connect the positive termi- Output Current nal of the 200mA load to the VOUT PCB pad and the High 91.13% Efficiency negative terminal to the nearest GND PCB pad. (V = 24V, V = 12V at 120mA) IN OUT 3) Connect the DMM in voltage-measurement mode 550kHz Switching Frequency 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 DMM displays 12V. Overcurrent and Overtemperature Protection (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 319-100452 Rev 0 10/19Evaluates: MAXM15068 12V MAXM15068 12V Output Evaluation Kit Output-Voltage Application Electro-Magnetic Interference (EMI) Detailed Description Compliance to conducted emissions (CE) standards The MAXM15068 EV kit is designed to demonstrate requires an EMI filter at the input of a switching power salient features of MAXM15068 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 con- RESET pad is available for monitoring if the converter junction with the schematic results in lower conducted emis- output voltage is in regulation. sions below CISPR22 Class B limits. The MAXM15068 EV kit PCB layout is also designed to limit radiated emissions Output Capacitor Selection from switching nodes of the power converter resulting in X7R ceramic output capacitors are preferred due to their radiated emissions below CISPR22 Class B limits. Further, stability over temperature in industrial applications. The capacitors (C1, C4, 0.1F/100V) and (C7, 0.1F/16V), help required output capacitor (C6) for 12V output is selected in attenuating high frequency noise. from Table 1 of the MAXM15068 data sheet as 4.7F/25V. Hot-Plug-In and Long Input Cables Adjusting Output Voltage The MAXM15068 EV kit PCB provides an optional The MAXM15068 supports an adjustable output-voltage electrolytic capacitor (C2, 4.7F/100V) to dampen input range, from 5V to 12V, using a feedback resistive divider voltage peaks and oscillations that can arise during hot- from V to FB. Output voltage can be programmed OUT plug-in and/or due to long input cables. This capacitor using the values given in Table 1 of the MAXM15068 data limits the peak voltage at the input of the MAXM15068 sheet. For 12V output, R3 is chosen as 931k, and R4 is power module, when the EV kit is powered directly from a chosen as 75k. precharged capacitive source or an industrial backplane PCB. Long input cables, between input power source and Enable/Undervoltage-Lockout (EN/UVLO) the EV kit circuit can cause input-voltage oscillations due Programming The MAXM15068 offers an adjustable input undervoltage- Table 1. UVLO Enable/Disable lockout feature. In this EV kit, for normal operation, leave Configuration (J1) jumper J1 open. When J1 is left open, the MAXM15068 is enabled when the input voltage rises above 15.5V. To MAXM15068 disable MAXM15068, install a jumper across pins 2-3 on POSITION EN/UVLO PIN OUTPUT J1. See Table 1 for J1 settings. A potential divider formed Connected to the center Programmed to by R1 and R2 sets the input voltage (V ) at which the INU Not node of resistor-divider startup at desired module is enabled. The value of resistor R1 is chosen Installed* R1 and R2. input-voltage level. to be 2.2M, and R2 is calculated using the following equation: Enabled if V is IN 1-2 Connected to V IN greater than V IN(MIN). R 1.215 1 R = 2 2-3 Connected to GND Disabled ( V 1.215 ) INU *Default position where R1 and R2 are in k, For MAXM15068 to turn on at 15.5V input, the Resistor VIN EMI VIN R2 is calculated to be 191k. VIN EMI L Input Capacitor Selection EMI 1 The input capacitor serves to reduce the current peaks 82H CEMI 2 CEMI 1 drawn from the input power supply and reduces switching frequency ripple at the input. The input capacitance must 1F 0.47F be greater than or equal to the value given in Table 1 of MAXM15068 data sheet. Input capacitor C3 is chosen to be 1F/100V. Figure 1. EMI Filter Components Maxim Integrated 2 www.maximintegrated.com