DEMO MANUAL DC1759A LTM4620A High Efficiency, Dual 13A Step-Down Power Module Regulator DESCRIPTION Demonstration circuit 1759A features the LTM 4620AEV, down through the TRACK/SS pin. The output can be set the high efficiency, high density, dual 13A, switch mode up to either coincidentally or ratiometrically track with step-down power module regulator. The input voltage is another supplys output. Remote output voltage sensing from 5.5V to 16V. The output voltage is programmable is available for improved output voltage regulation at from 0.6V to 5V. DC1759A can deliver 13A maximum the load point. These features and the availability of the current from each channel. As explained in the data sheet, LTM4620AEV in a compact 15mm 15mm 4.41mm output current derating is necessary for certain V , V , LGA package make it ideal for use in many high density IN OUT and thermal conditions. The board operates in continuous point-of-load regulation applications. The LTM4620A data conduction mode in heavy load conditions. For high effi- sheet must be read in conjunction with this demo manual ciency at low load currents, the MODE jumper (JP1) selects for working on or modifying the demo circuit 1759A. pulse-skipping mode for noise sensitive applications or Design files for this circuit board are available at Burst Mode operation in less noise sensitive applications. DEMO MANUAL DC1759A PERFORMANCE SUMMARY (T = 25C) A PARAMETER CONDITION VALUE Input Voltage Range 5.5V ~ 16V Output Voltage V V = 5.5V ~ 16V, I = 0A ~ 13A, JP1: CCM 3.3V 1.5% OUT1 IN OUT1 Output Voltage V V = 5.5V ~16V, I = 0A ~ 13A, JP1: CCM 5V 1.5% OUT2 IN OUT2 Per-Channel Maximum Continuous Output Current Derating is Necessary for Certain V , V and Thermal Conditions, 13A (per-Channel) IN OUT See Data Sheet for Detail. Default Operating Frequency 750kHz Resistor Programmable Frequency Range 250kHz to 780kHz External Clock Sync. Frequency Range 400kHz to 780kHz Efficiency of Channel 1 V = 12V, V = 3.3V, I = 13A, f = 750kHz 91.7% See Figure 3 IN OUT1 OUT1 SW Efficiency of Channel 2 V = 12V, V = 5V, I = 13A, f = 750kHz 93.8% See Figure 4 IN OUT2 OUT2 SW Load Transient of Channel 1 V = 12V, V = 3.3V, I = 6.5A ~ 13A See Figure 5 IN OUT1 SETP Load Transient of Channel 2 V = 12V, V = 5V, I = 6.5A ~ 13A See Figure 6 IN OUT2 SETP QUICK START PROCEDURE Demonstration circuit 1759A is easy to set up to evalu- 5. (Optional) For optional load transient test, apply an ate the performance of the LTM4620AEV. Please refer to adjustable pulse signal between IOSTEP CLK and GND Figure 2 for proper measurement setup and follow the test point. Pulse amplitude (3V ~ 3.5V) sets the load procedure below: 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: (<1%) 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 1 SEL. SEL. PHASE or channel 2 correspondingly. CCM ON ON SOFT- SOFT- 90 START START 6. (Optional) LTM4620A 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 (0V ~ 5V, square wave) on the and meters as shown in Figure 2. Preset the load to 0A CLKIN test point. and V supply to 12V. IN 7. (Optional) The outputs of LTM4620A can track another 3. Turn on the power supply at the input. The output supply. The jumpers JP4 and JP5 allow choosing soft- voltage in channel 1 should be 3.3V 1.5% (3.2505V start or output tracking. If tracking external voltage is ~ 3.3495V) and the output voltage in channel 2 should selected, the corresponding test points, TRACK1 and be 5V 1.5% (4.925V ~ 5.075V). TRACK2, need to be connected to a valid voltage signal. 4. Once the proper output voltage is established, adjust the 8. (Optional) LTM4620A can be configured for a 2-phase load within the operating range and observe the output single output at up to 26A on DC1759A. Install 0 voltage regulation, output voltage ripple, efficiency and resistors on R14, R17, R28, R39 and remove R7, other parameters. Output ripple should be measured R19. 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. dc1759af 2