DEMO MANUAL DC2448A-A LTM4636 High Efficiency, PolyPhase 80A Step-Down Power Module Regulator DESCRIPTION Demonstration circuit DC2448A-A features a PolyPhase noise sensitive applications or Burst Mode operation in design using the LTM 4636EY, a 40A high efficiency, less noise sensitive applications. The MODE PLLIN pin switch mode step-down power Module regulator. The also allows the LTM4636 to synchronize to an external input voltage range is from 4.7V to 15V. When V < 5.5V, clock signal. The phase shift between the two phases is IN short PVCC to VIN with R1 = 0, and set R3 = 0 and 180 degree. DC2448A-A has the option of choosing both remove R2. The output voltage range is 0.6V to 3.3V. The internal and external compensation circuit for LTM4636. DC2448A-A can deliver a nominal 80A output current. As The LTM4636 data sheet must be read in conjunction with explained in the data sheet, output current derating is nec- this demo manual prior to working on or modifying demo essary for certain V , V , and thermal conditions. The circuit DC2448A-A. IN OUT board operates in continuous conduction mode in heavy Design files for this circuit board are available at load conditions. For high efficiency at low load currents, DEMO MANUAL DC2448A-A PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETER CONDITIONS VALUE Input Voltage Range 4.7V to 15V Output Voltages 0.9V 1.3% Maximum Continuous Output Current Derating is necessary for certain operating conditions. See data sheet for details. 80A DC Operating Frequency 350kHz Efficiency V = 12V, V = 0.9V, I = 80A 87.0% Figure2 IN OUT OUT Load Transient V V = 12V, V = 0.9V, I = 0A TO 20A 109mV Figure3 OUT(P-P) IN OUT STEP QUICK START PROCEDURE Demonstration circuit DC2448A-A is an easy way to 4. Vary the input voltage from 6V to 15V and adjust evaluate the performance of PolyPhase operation of the the load current from 0A to 80A. Observe the output LTM4636EY. 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) LTM4636 can be synchronized to an external CCM ON clock signal. Apply a clock signal (0V to 5V, square wave) on the MODE PLLIN test point. 2. With power off, connect the input power supply, load 7. (Optional) The outputs of LTM4636 can track another and meters as shown in Figure1. Preset the load to 0A supply. The output voltage tracks the voltage on TRACK and V supply to 12V. IN when a valid signal is applied on the test point. 3. Turn on the power supply at the input. The output volt- age should be 0.9V 1.3% (0.888V to 0.912V). UG-1332 Rev 0 2