DEMO MANUAL DC2157A LTM4630-1 Dual 18A or Single 36A Module Regulator with 0.8% DC and 3% Transient Accuracy Description Demonstration circuit 2157A features the LTM 4630EY-1, how its output ramps up and down through the TRACK/ the high efficiency, high density, dual 18A, switch mode SS pin. The output can be set up to either coincidentally or step-down power module regulator with 0.8% total DC ratiometrically track with another supplys output. Remote output accuracy. The input voltage is from 4.5V to 15V. output voltage sensing is available for improved output The output voltage is programmable from 0.6V to 1.8V. voltage regulation at the load point. These features and DC2157A can deliver up to 18A maximum in each channel. the availability of the LTM4630-1 in a compact 16mm With the help of external compensation, 3% transient ac- 16mm 5.01mm BGA package make it ideal for use in curacy can be achieved with 25% load step. As explained many high density point-of-load regulation applications. in the data sheet, output current derating is necessary The LTM4630-1 data sheet must be read in conjunction for certain V , V , and thermal conditions. The board with this demo manual for working on or modifying the IN OUT operates in continuous conduction mode in heavy load demo circuit DC2157A. conditions. For high efficiency at low load currents, the Design files for this circuit board are available at MODE jumper (JP1) selects pulse-skipping mode for noise DEMO MANUAL DC2157A p s Specifications are at T = 25C A PARAMETER CONDITIONS VALUE Input Voltage Range 4.5V ~ 15V Output Voltage V (LTM4630-1A) V = 4.5V ~ 15V, I = 0A ~ 18A, JP1: CCM 1.5V 0.8% (1.488V ~ 1.512V) OUT1 IN OUT1 Output Voltage V (LTM4630-1A) V = 4.5V ~ 15V, I = 0A ~ 18A, JP1: CCM 1.0V 0.8% (0.992V ~ 1.008V) OUT2 IN OUT2 Per Channel Maximum Continuous Output Current Derating Is Necessary for Certain V , V and Thermal 18A IN OUT Conditions, See 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 2 IN OUT1 OUT1 SW Efficiency of Channel 2 V = 5V, V = 1.0V, I = 18A, f = 500kHz 86.2% See Figure 3 IN OUT2 OUT2 SW Load Transient of Channel 1 V = 12V, V = 1.5V, I = 0A ~ 4.5A See Figure 4 IN OUT1 STEP Load Transient of Channel 2 V = 12V, V = 1.0V, I = 0A ~ 4.5A See Figure 5 IN OUT2 STEP Quick s p D 5. (Optional) For optional load transient test, apply an Demonstration circuit DC2157A is easy to set up to evalu- adjustable pulse signal between IOSTEP CLK and GND ate the performance of the LTM4630-1. Please refer to test point. Pulse amplitude (3V ~ 3.5V) sets the load Figure 1 for proper measurement setup and follow the step current amplitude. The output transient current procedure below: 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 JP1 JP2 JP3 JP4 JP5 JP6 load circuit. Switch the jumper resistors R34 or R35 TRACK1 TRACK2 CLKOUT (on the backside of boards) to apply load transient on MODE RUN1 RUN2 SEL. SEL. PHASE channel1 or channel 2 correspondingly. CCM ON ON SOFT- SOFT- 90 START START 6. (Optional) LTM4630-1 can be synchronized to an ex- ternal clock signal. Place the JP1 jumper on EXT CLK 2. With power off, connect the input power supply, load and apply a clock signal (0~5V, square wave) on the and meters as shown in Figure 1. Preset the load to 0A CLKIN test point. and V supply to 12V. IN 7. (Optional) The outputs of LTM4630-1 can track another 3. Turn on the power supply at the input. The output voltage supply. The jumpers JP4 and JP5 allow choosing soft- in channel 1 should be 1.5V 0.8% (1.488V ~ 1.512V) start or output tracking. If tracking external voltage is and the output voltage in channel 2 should be 1.0V 0.8% selected, the corresponding test points, TRACK1 and (0.992V ~ 1.008V). TRACK2, need to be connected to a valid voltage signal. 4. Once the proper output voltage is established, adjust the 8. (Optional) LTM4630-1 can be configured for a 2-phase load within the operating range and observe the output single output at up to 36A on DC2157A. 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 equation: at J1 and J2 with BNC cables. 50 termination should V = 0.6V(1 + 60.4k/R25) OUT be set on the oscilloscope or BNC cables. dc2157afc 2 ure roce tart ummary erformance