DEMO MANUAL DC1892A LTM4630EV High Efficiency, Dual 18A Step-Down Power Module Regulator DESCRIPTION Demonstration circuit 1892A features the LTM 4630EV, allows the user to program how its output ramps up and the high efficiency, high density, dual 18A, switch mode down through the TRACK/SS pin. The output can be set step-down power module regulator. The input voltage is up to either coincidentally or ratiometrically track with from 4.5V to 15V. The output voltage is programmable from another supplys output. Remote output voltage sens- 0.6V to 1.8V. DC1892A can deliver up to 18A maximum ing is available for improved output voltage regulation in each channel. As explained in the LTM4630 data sheet, at the load point. These features and the availability of output current derating is necessary for certain V , V the LTM4630EV in a compact 16mm 16mm 4.41mm IN OUT and thermal conditions. The board operates in continuous LGA package make it ideal for use in many high density conduction mode in heavy load conditions. For high effi- point-of-load regulation applications. The LTM4630 data ciency at low load currents, the MODE jumper (JP1) selects sheet must be read in conjunction with this demo manual pulse-skipping mode for noise-sensitive applications or for working on or modifying the demo circuit DC1892A. Burst Mode operation in less noise-sensitive applications. Design files for this circuit board are available at Two outputs can be connected in parallel for a single 36A DEMO MANUAL DC1892A PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETER CONDITIONS/NOTES VALUE Input Voltage Range 4.5V ~ 15V Output Voltage V V = 4.5 ~ 15V, I = 0A ~ 18A, JP1: CCM 1.5V 1.5% (1.4775V ~ 1.5225V) OUT1 IN OUT1 Output Voltage V V = 4.5 ~ 15V, I = 0A ~ 18A, JP1: CCM 1V 1.5% (0.985V ~ 1.015V) OUT2 IN OUT2 Per Channel Maximum Continuous Output Current Derating Is Necessary for Certain V , V and Thermal 18A IN OUT Conditions. See the LTM4630 Data Sheet for Details Default Operating Frequency 500kHz Resistor Programmable Frequency Range 250kHz to 780kHz External Clock Sync. Frequency Range 400kHz to 780kHz Efficiency of Channel 1 V = 5V, V = 1.5V, I = 18A, f = 500kHz 89.7%, See Figure 3 IN OUT1 OUT1 SW Efficiency of Channel 2 V = 5V, V = 1V, I = 18A, f = 500kHz 84.8%, See Figure 4 IN OUT2 OUT2 SW Load Transient of Channel 1 V = 12V, V = 1.5V, I = 9 ~ 18A See Figure 5 IN OUT1 SETP Load Transient of Channel 2 V = 12V, V = 1V, I = 9 ~ 18A See Figure 6 IN OUT2 SETP QUICK START PROCEDURE Demonstration circuit DC1892A is easy to set up to evalu- 5. (Optional) For optional load transient test, apply an ate the performance of the LTM4630EV. Please refer to adjustable pulse signal between the IOSTEP CLK and Figure 2 for proper measurement setup and follow the GND test points. Pulse amplitude (3V ~ 3.5V) sets the procedure below: load step current amplitude. The output transient current can be monitored at the BNC connector J3 (15mV/A). 1. Place jumpers in the following positions for a typical The pulse signal should have very small duty cycle application: (< 10%) to limit the thermal stress on the transient load JP1 JP2 JP3 JP4 JP5 JP6 circuit. Switch the jumper resistors R34 or R35 (on the MODE RUN1 RUN2 TRACK1 TRACK2 CLKOUT backside of boards) to apply load transient on channel SEL. SEL. PHASE 1 or channel 2, correspondingly. CCM ON ON SOFT- SOFT- 90 START START 6. (Optional) LTM4630 can be synchronized to an external clock signal. Place the JP1 jumper on EXT CLK and 2. With power off, connect the input power supply, load apply a clock signal (0 ~ 5V, square wave) on the CLKIN and meters, as shown in Figure 1. Preset the load to test point. 0A and the V supply to 12V. IN 7. (Optional) The outputs of LTM4630 can track another 3. Turn on the power supply at the input. The output volt- supply. The jumpers JP4 and JP5 allow choosing soft- age in channel 1 should be 1.5V 1.5% (1.4775V ~ start or output tracking. If tracking external voltage is 1.5225V) and the output voltage in channel 2 should selected, the corresponding test points, TRACK1 and be 1V 1.5% (0.985V ~ 1.015V). TRACK2, need to be connected to a valid voltage signal. 4. Once the proper output voltage is established, adjust the 8. (Optional) LTM4630 can be configured for a 2-phase load within the operating range and observe the output single output at up to 36A on DC1892A. Install 0 voltage regulation, output voltage ripple, efficiency and resistors on R14, R17, R28, R39 and remove R7, R19. other parameters. Output ripple should be measured Output voltage is set by R25 based on the equation: at J1 and J2 with BNC cables. 50 termination should 60.4k be set on the oscilloscope or BNC cables. V = 0.6V 1 + OUT R25 dc1892afb 2