DEMO MANUAL DC2616A-C LTM4645 High Efficiency, PolyPhase 100A Step-Down Power Module Regulator DESCRIPTION Demonstration circuit 2616A-C features a polyphase mode in heavy load conditions. For high efficiency at low design using the LTM 4645EY, a 25A high efficiency, load currents, the MODE PLLIN jumper selects pulse- switch mode step-down power Module regulator. The skipping mode for noise sensitive applications or burst input voltage range is from 6V to 15V. To use DC2616A-C mode operation in less noise sensitive applications. The for input voltage range from 4.7V to 6V, connect INTV MODE PLLIN pin also allows the LTM4645 to synchro- CC to SV (change R22, R42, R55, R68 from OPT to 0), nize to an external clock signal. The phase shift between IN DRV to V (change R21, R38, R52, R65 from 0 to two adjacent phases is 90 degrees. DC2616A-C has the CC IN OPT, R2, R39, R53, R66 from OPT to 0). The output volt- option of choosing both internal and external compensa- age range is 0.6V to 1.8V. The DC2616A-C can deliver a tion circuit for LTM4645. The LTM4645 data sheet must nominal 100A output current with four LTM4645 modules be read in conjunction with this demo manual prior to in parallel. As explained in the data sheet, output current working on or modifying demo circuit DC2616A-C. derating is necessary for certain V , V , and thermal IN OUT Design files for this circuit board are available. conditions. The board operates in continuous conduction All registered trademarks and trademarks are the property of their respective owners. BOARD PHOTO Rev. 0 1DEMO MANUAL DC2616A-C PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETER CONDITIONS VALUE Input Voltage Range 6V to 15V Output Voltages 1.0V 1.2% Maximum Continuous Output Current De-rating is Necessary for Certain Operating 100ADC Conditions. See Data Sheet for Details. Operating Frequency 600kHz Efficiency V = 12V, V = 1.0V, I = 100A 83.6% Figure2 IN OUT OUT Load Transient V = 12V, V =1.0V, I = 0A to 25A 53.8mV Figure3 IN OUT STEP QUICK START PROCEDURE Demonstration circuit DC2616A-C is an easy way to 4. Vary the input voltage from 6V to 15V and adjust the evaluate the performance of polyphase operation of the load current from 0A to 100A. Observe the output LTM4645EY. Due to the high input/output current, the voltage regulation, ripple voltage, efficiency, and other user should select the proper input supply/load/cable parameters. which can sustain the full load operation. Please refer to 5. (Optional) For optional load transient test, apply an Figure1 for proper measurement equipment setup and adjustable pulse signal between IOSTEP CLK and GND follow the procedure below: test points. The pulse amplitude sets the load step cur- 1. Place jumpers in the following positions for a typical rent amplitude. Keep the pulse width short (<1ms) and application: pulse duty cycle low (<5%) to limit the thermal stress on the load transient circuit. MODE RUN 6. (Optional) LTM4645 can be synchronized to an external CCM ON clock signal. Apply a clock signal (0V to 5V, square 2. With power off, connect the input power supply, load wave) on the MODE PLLIN test point. and meters as shown in Figure1. Preset the load to 0A 7. (Optional) The outputs of LTM4645 can track another and V supply to 12V. IN supply. The output voltage tracks the voltage on TRACK 3. Turn on the power supply at the input. The output volt- when a valid signal is applied on the test point. age should be 1.0V 1.2% (0.988V to 1.012V). Rev. 0 2