DEMO MANUAL DC2455A-A LTM4650EY-1 High Efficiency, PolyPhase 100A Step-Down Power Module Regulator 2 LTM4650EY-1, 100A Description Demonstration Circuit 2455A-A features PolyPhase design TRACK pin. The output voltage is tightly regulated between + using the LTM 4650EY-1 (B-grade), the high efficiency, V and V through remote output voltage sensing O O high density, dual 25A, switch mode step-down power which improves output voltage regulation at heavy loads. module regulator. The input voltage is from 4.5V to 15V. These features and the availability of the LTM4650EY-1 The output voltage is jumper selectable from 0.9V to 1.8V. in a compact 16mm 16mm 5.01mm BGA package DC2455A-A can deliver nominal 100A output current. As make it ideal for use in many high-density point-of-load explained in the data sheet, output current de-rating is regulation applications. The LTM4650-1 data sheet must necessary for certain V , V , and thermal conditions. The be read in conjunction with this demo manual for working IN OUT LTM4650-1 on DC2455A-A always operate in continuous on or modifying the demo circuit DC2455A-A. conduction mode. The switching frequency can be pro- Design files for this circuit board are available at grammed through a resistor or can be synchronized to an DEMO MANUAL DC2455A-A p erformance s Specifications are at T = 25C A PARAMETER CONDITIONS / NOTES VALUE Input Voltage Range 4.5V ~ 15V Output Voltage V V = 4.5V to 15V, I = 0A to 100A, JP5: 1.0V 1.0V 1.5% (0.985V ~ 1.015V) OUT IN OUT Maximum Continuous Output Current De-rating is necessary for certain V , V and thermal 100A IN OUT conditions, see data sheet for detail. Default Operating Frequency 500kHz Resistor Programmable Frequency Range 400kHz 780kHz External Clock Sync. Frequency Range 400kHz 780kHz Efficiency V = 12V, V = 1.0V, I = 100A, f = 500kHz 86.5% See Figure 3 IN OUT OUT SW Load Transient V = 12V, V = 1.0V, I = 50A to 75A < 57mV, See Figure 4 IN OUT STEP Quick s tart p D Demonstration circuit DC2455A-A is easy to set up to and other parameters. Output voltage ripple should be evaluate the performance of PolyPhase operation of the measured at J11 with BNC cables. 50 termination LTM4650EY-1. Due to the high input/output current, user should be set on the oscilloscope or BNC cables. should select the proper input supply/load/cable which 5. (Optional) For optional load transient test, apply an ad- can sustain the full load operation. Its recommended to justable pulse signal between IOSTEP CLK and GND pull load current from J2 and J4. The load current pulled test point. Pulse amplitude (3V~3.5V) sets the load step from J5 and J6 shouldnt exceed 25A. Please refer to current amplitude. The output transient current can be Figure 2 for proper measurement setup and follow the monitored at the BNC connector J12 (5mV/A). The pulse procedure below: signal should be very small duty cycle (< 10%) to limit 1. Place jumpers in the following positions for a typical the thermal stress on the transient load circuit. 1.0V application: OUT 6. (Optional) LTM4650-1 can be synchronized to an external clock signal. Place the JP1 jumper on EXT JP1 JP2 JP4~JP8 and apply a clock signal (0V~5V, square wave) on the CLK RUN V SELECT OUT EXT CLK test point. INT OFF ON JP5 / 1.0V 7. (Optional) The outputs of LTM4650-1 can track another supply. The output voltage tracks the voltage on TRACK 2. With power off, connect the input power supply, load when a valid signal is applied on the test point. and meters as shown in Figure 2. Preset the load to 0A and V supply to 12V. 8. (Optional) DC2455A-A can be configured to a dual IN outputs configuration with V at 75A load current and O 3. Turn on the power supply at the input. Place JP2 to ON V at 25A load current. Stuff 0 resistor on R61 and + O2 position. The output voltage between V and V O O 0.1F on C14. Remove R22, R23, R24, R26, R27, R28, should be 1.0V 1.5% (0.985V~1.015V). R32, R33, R35. Output voltage V is set by R37 based O2 4. Once the proper output voltage is established, adjust the on the equation V = 0.6V(1 + 60.4k/R37). O2 load within the operating range and observe the output voltage regulation, output voltage ripple, efficiency dc2455aaf 2 ure roce ummary