DEMO MANUAL DC2268A-I LTM4650A-1 Dual 25A or Single 50A Module Regulator DESCRIPTION Demonstration circuit 2268A-I is a high efficiency, high the user to program how its output ramps up and down density, dual 8A, switch mode step-down power supply on through the TRACK/SS pin. Remote output voltage sens- a compact 1.5 1.2 PCB. It features the LTM 4650A-1 ing is available for improved output voltage regulation Module regulator. The input voltage is from 4.5V to at the load point. An optional input inductor L1 reduces 16V. The output voltage is programmable from 0.6V to the EMI noise for noise sensitive applications. DC2268A 5.3V. DC2268A-I can deliver up to 25A maximum in each can be easily inserted to an edge connector for testing channel. As explained in the data sheet, output current and debugging. These features and the availability of the derating is necessary for certain V , V , and thermal LTM4650A-1 in a compact 16mm 16mm 4.41mm IN OUT conditions. The board operates in continuous conduc- LGA package make it ideal for use in many high-density tion mode in heavy load conditions. For high efficiency point-of-load regulation applications. The LTM4650A-1 at low load currents, the resistor jumper (R1/R2) selects data sheet must be read in conjunction with this demo pulse-skipping mode for noise sensitive applications or manual for working on or modifying the DC2268A-I. Burst-Mode in less noise sensitive applications. Two out- Design files for this circuit board are available. puts can be connected in parallel for a single 50A output All registered trademarks and trademarks are the property of their respective owners. solution with optional jumper resistors. The board allows BOARD PHOTO Figure1. LTM4650A-1/DC2268A-I Demo Board Rev. 0 1DEMO MANUAL DC2268A-I PERFORMANCE SUMMARY Specifications are at T = 25C A Table1. PARAMETER CONDITIONS VALUE Input Voltage Range 4.5V ~ 16V Output Voltage V V = 4.5~16V, I = 0A ~25A 3.3V 1.5% OUT1 IN OUT1 Output Voltage V V = 4.5~16V, I = 0A ~25A 1.5V 1.5% OUT2 IN OUT2 Per-Channel Maximum Continuous Output Current De-rating is necessary for certain V , V and thermal conditions 25A (per channel) IN OUT Default Operating Frequency 600kHz External Clock Sync. Frequency Range 400kHz to 780kHz Efficiency of Channel 1 V = 12V, V = 3.3V, I = 25A, f = 600kHz 94.4%, see Figure3 IN OUT1 OUT1 SW Efficiency of Channel 2 V = 12V, V = 1.5V, I = 25A, f = 600kHz 90.0%, see Figure4 IN OUT2 OUT2 SW Load Transient of Channel 1 V = 12V, V = 3.3V, I = 12.5A ~ 18.75A V = 157mV, see Figure5 IN OUT1 STEP OPP Load Transient of Channel 2 V = 12V, V = 1.5V, I = 12.5A ~ 18.75A V = 127mV, see Figure6 IN OUT2 STEP OPP QUICK START PROCEDURE DC2268A-I is easy to set up to evaluate the performance NOTE: Due to very small PCB size of the DC2268A of the LTM4650A-1. It can be easily inserted to an edge board, the LTM43650A-1 module can be quite hot at connector (SAMTEC MEC2-20-01-L-DV--TR) for testing heavy load. Cooling air is required. See Figures 7 and 8 and debugging. Please refer to Figure2 for proper mea- 4. Once the proper output voltage is established, adjust surement setup and follow the procedure below: the load within the operating range and observe the 1. Pull up the RUN1(J1 Pin 22) and RUN2(J1 Pin 24) output voltage regulation, output voltage ripple, effi- between 1.4V to 5V or leave them floating. ciency and other parameters. Output ripple should be measured at C and C . o3 o4 2. With power off, connect the input power supply, load and meters as shown in Figure2. Preset the load to 0A 5. (Optional) LTM4650A-1 can be synchronized to an and V supply to 12V. external clock signal. Remove R2 and apply a clock IN signal (0V~5V, square wave) to MODE-PLLIN pin. 3. Turn on the power supply at the input. The output voltage in channel 1 should be 3.3V 1.5% (3.25V ~ 6. (Optional) LTM4650A-1 can be configured for a 2-phase 3.35V) and the output voltage in channel 2 should be single output at up to 36A on DC2268A-I. Install 0 1.5V 1.5% (1.478V ~ 1.523V), resistors on R26, R27, R28, R29, R32, and remove R14, R18 R30. Output voltage is set by R7 based on equation V = 0.6V (1 + 60.4k/R7). OUT Table2. DC2268A Demo Circuit DEMO BOARD NUMBER Module REGULATOR ON THE BOARD OUTPUT CURRENT DC2268A-A LTM4620 13A,13A DC2268A-B LTM4620A 13A,13A DC2268A-C LTM4628 8A, 8A DC2268A-D LTM4630 18A,18A DC2268A-E LTM4630-1 18A,18A DC2268A-F LTM4630A 18A, 18A DC2268A-G LTM4631 10A, 10A DC2268A-H LTM4650-1 25A, 25A DC2268A-I LTM4650A-1 25A, 25A Rev. 0 2