DEMO MANUAL DC2455A-B LTM4650EY-1 High Efficiency, PolyPhase 150A Step-Down Power Module Regulator 3 LTM4650EY-1, 150A Description Demonstration Circuit 2455A-B 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-B can deliver nominal 150A 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-B always operate in continuous on or modifying the demo circuit DC2455A-B. 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-B 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 150A, 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 150A 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 = 150A, f = 500kHz 86.1% See Figure 3 IN OUT OUT SW Load Transient V = 12V, V = 1.0V, I = 72A to 112.5A < 53mV, See Figure 4 IN OUT STEP Quick s tart p D Demonstration circuit DC2455A-B 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 can sustain the full load operation. Its recommended to adjustable pulse signal between IOSTEP CLK and pull load current from J2 and J4. The load current pulled GND test point. Pulse amplitude (3V~3.5V) sets the from J5 and J6 shouldnt exceed 25A. Please refer to load step current amplitude. The output transient current Figure 2 for proper measurement setup and follow the can be monitored at the BNC connector J12 (5mV/A). procedure below: The pulse signal should be very small duty cycle (< 1. Place jumpers in the following positions for a typical 10%) to limit the thermal stress on the transient load 1.0V application: circuit. OUT 6. (Optional) LTM4650-1 can be synchronized to an exter- JP1 JP2 JP4~JP8 nal clock signal. Place the JP1 jumper on EXT and apply CLK RUN V SELECT OUT a clock signal (0~5V, square wave) on the EXT CLK INT OFF ON JP5 / 1.0V test point. 7. (Optional) The outputs of LTM4650-1 can track another 2. With power off, connect the input power supply, load supply. The output voltage tracks the voltage on TRACK and meters as shown in Figure 2. Preset the load to 0A when a valid signal is applied on the test point. and V supply to 12V. IN 8. (Optional) DC2455A-B can be configured to a dual 3. Turn on the power supply at the input. Place JP2 to ON outputs configuration with V at 125A load current + O position. The output voltage between V and V O O and V at 25A load current. Stuff 0 resistor on R61 O2 should be 1.0V 1.5% (0.985V~1.015V). and 0.1F on C14. Remove R22, R23, R24, R26, R27, 4. Once the proper output voltage is established, adjust the R28, R32, R33, R35. Output voltage V is set by R37 O2 load within the operating range and observe the output based on the equation V = 0.6V(1 + 60.4k/R37). O2 voltage regulation, output voltage ripple, efficiency dc2455abf 2 ure roce ummary