DEMO MANUAL DC1297B LTM4612 EN55022B Compliant 36V, 5A Step-Down Module Regulator DESCRIPTION Demonstration circuit DC1297B features the LTM 4612EV, to coincidentally or ratiometrically track to another voltage an EN55022 Class B certified synchronous step-down rail. The LTM4612 data sheet must be read in conjunction power module. The board accepts an input voltage from with this demo manual for working on or modifying the 5V to 36V and delivers a jumper programmable output demo circuit 1297B. voltage of 3.3V, 5V or 12V. The rated load current is 5A for Design files for this circuit board are available at 3.3V/5V, 3A for 12V V . Current derating is necessary OUT DEMO MANUAL DC1297B QUICK START PROCEDURE Demonstration circuit DC1297B is an easy way to evalu- 5. To measure input and output ripple, please refer to ate the performance of the LTM4612EV. Please refer to Figure 2 for proper setup. Figure 1 for proper measurement equipment setup and 6. For optional load transient test, apply adjustable pulse follow the procedure below: signal between IOSTEP CLK and GND pins. The pulse 1. Place jumpers in the following positions for a typical amplitude sets the current step. The pulse signal 5V application: should have very small duty cycle (<5%) to limit the OUT thermal stress on the transient load circuit. The output V OUT transient current can be monitored at BNC connector MODE MARG1 MARG0 SELECT RUN J3 (10mV/A), the output voltage can be monitored at CCM LO LO 5V ON BNC connector J4. 2. With power off, connect the input power supply, load 7. Due to the 400ns minimum off time limit of LTM4612, and meters as shown in Figure 1. Preset the load to 0A V needs to be higher than 18.5V for 12V V , and IN OUT and the input supply to be 12V. higher than 5.85V for 5V V . Otherwise, the switching OUT 3. Turn on the power at the input. The output voltage frequency needs to be reduced by adding a resistor at should be 5V 2% (4.9V~5.1V). R6. Please refer to the LTM4612 datasheet for details. 4. Once the proper output voltage is established, adjust the load within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. dc1297bf 2