DEMO MANUAL DC2603A-A LTM4650AEY Dual 25A or Single 50A DC/DC Module Regulator DESCRIPTION Demonstration circuit 2603A-A features the put solution with optional jumper resistors. The board LTM 4650AEY, the high efficiency, high density, dual 25A, allows the user to program how its output ramps up and single 50A switch mode step-down power module regu- down through the TRACK/SS pin. The output can be set lator. The input voltage is from 4.5V to 16V. The output up to either coincidentally or ratiometrically track with voltage is programmable from 0.6V to 5.5V. DC2603A-A another supplys output. Remote output voltage sens- can deliver 25A maximum current from each channel. ing is available for improved output voltage regulation at The board designs with minimum components to dem- the load point. These features and the availability of the onstrate this high efficiency, high density Module . As LTM4650AEY in a compact 16mm 16mm 5.01mm explained in the data sheet, output current derating is BGA package make it ideal for use in many high-density necessary for certain V , V , and thermal conditions. point-of-load applications. The LTM4650A data sheet IN OUT The board operates in continuous conduction mode in must be read in conjunction with this demo manual for heavy load conditions. For high efficiency at low load working on or modifying the demo circuit DC2603A-A. currents, the MODE jumper (JP1) selects pulse-skipping Design files for this circuit board are available at mode for noise sensitive applications or Burst Mode DEMO MANUAL DC2603A-A PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETER CONDITIONS VALUE Input Voltage Range 4.5V ~ 16V Output Voltage V V = 4.5~16V, I = 0~25A, JP1: CCM 1.5V 1% (1.485V ~ 1.515V) OUT1 IN OUT1 Output Voltage V V = 4.5~16V, I = 0~25A, JP1: CCM 3.3V 1% (3.267V ~ 3.333V) OUT2 IN OUT1 Per- Channel Maximum Continuous Output De-rating is Necessary for Certain V , V and Thermal 25A IN OUT Current Conditions, see Data Sheet for Detail Default Operating Frequency 600kHz Resistor Programmable Frequency Range 250kHz to 780kHz External Clock Sync. Frequency Range 400kHz to 780kHz Efficiency of Channel 1 V = 12V, V = 1.5V, I = 25A, f = 600 kHz 90.4%, See Figure 3 IN OUT OUT SW Efficiency of Channel 2 V = 12V, V = 3.3V, I = 25A, f = 600 kHz 94.2%, See Figure 4 IN OUT OUT SW Load Transient of Channel 1 V = 12V, V = 1.5V, I = 12.5~18.75A < 3% (90mV ), See Figure 5 IN OUT STEP P-P Load Transient of Channel 2 V = 12V, V = 3.3V, I = 12.5~18.75A < 3% (198mV ), See Figure 6 IN OUT STEP P-P QUICK START PROCEDURE Demonstration circuit DC2603A-A is easy to set up to 5. (Optional) For optional load transient test, apply an evaluate the performance of the LTM4650AEY. Please adjustable pulse signal between IOSTEP CLK and refer to Figure 2 for proper measurement setup and GND test point. Pulse amplitude (3V~3.5V) sets the follow the procedure below: load step current amplitude. The output transient current 1. Place jumpers in the following positions for a typical can be monitored at the BNC connector J3 (10mV/A). application: The pulse signal should have very small duty cycle (< 10%) to limit the thermal stress on the transient JP1 JP2 JP3 JP4 JP5 load circuit. Switch the jumper resistors R34 or R35 MODE RUN1 RUN2 TRACK1 SEL TRACK2 SEL (on the backside of boards) to apply load transient on CCM ON ON SOFT-START SOFT-START channel 1 or channel 2 correspondingly. 6. (Optional) LTM4650A can be synchronized to an 2. With power off, connect the input power supply, load external clock signal. Place the JP1 jumper on EXT CLK and meters as shown in Figure 2. Preset the load to 0A and apply a clock signal (0V~5V, square wave) on the and V supply to 12V. IN CLKIN test point. 3. Turn on the power supply at the input. The output voltage 7. (Optional) The outputs of LTM4650A-1 can track another in channel 1 should be 1.5V 1.0% (0.985V~1.015V) supply. The jumpers JP4 and JP5 allow choosing soft- and the output voltage in channel 2 should be 3.3V1.0% start or output tracking. If tracking external voltage is (3.267V~3.333V) selected, the corresponding test points, TRACK1 and 4. Once the proper output voltage is established, adjust the TRACK2, need to be connected to a valid voltage signal. load within the operating range and observe the output 8. (Optional) LTM4650A-1 can be configured for a 2-phase voltage regulation, output voltage ripple, efficiency and single output at up to 50A on DC2603A-A. Install 0 resis- other parameters. Output ripple can be measured at J1 tors on R14, R17, R28, R39, R43, R44, R45 and remove and J2 with BNC cables.50 termination should be set R7, R19. Output voltage is set by R25 based on equation: on the oscilloscope or BNC cables. 60.4k V =0.6V 1+ OUT R25 UG-1346 Rev A 2