DEMO MANUAL DC1905A LTM4633 High Efficiency, Triple 10A Step-Down Module Regulator Description Demonstration circuit DC1905A features the LTM 4633EY, currents, the MODE jumper (JP4) selects pulse-skipping a high efficiency, triple 10A step-down power Module mode for noise sensitive applications or Burst-Mode regulator. The input voltage range is from 4.7V to 16V with operation in less noise sensitive applications. Channel 1 common input source, or 2.375V to 16V with an external bias and 2 can be connected in parallel for a single 20A output supply. The output voltage range is 0.8V to 1.8V for Channel 1 solution with optional jumper resistors. The LTM4633 data and Channel 2, 0.8V to 5.5V for Channel 3. Derating is sheet must be read in conjunction with this demo manual necessary for certain V , V , frequency and thermal con- prior to working on or modifying demo circuit DC1905A. IN OUT ditions. The DC1905A offers access to the TRACK/SS pins Design files for this circuit board are available at allowing the user to program output tracking or soft-start DEMO MANUAL DC1905A p s Specifications are at T = 25C A PARAMETER CONDITIONS VALUE Input Voltage Range 4.7V to 16V Output Voltages 1.0V, 1.2V, 3.3V 1.5% Maximum Continuous Output Current Derating Is Necessary for Certain Operating Conditions. 10ADC for Each Channel See Data Sheet for Details Operating Frequency 750kHz Efficiency of Channel 1 V = 12V, V = 1.0V, I = 10A 77% See Figure 2 IN OUT1 OUT1 Efficiency of Channel 2 V = 12V, V = 1.2V, I = 10A 81% See Figure 3 IN OUT2 OUT2 Efficiency of Channel 3 V = 12V, V = 3.3V, I = 10A 91% See Figure 4 IN OUT3 OUT3 Load Transient of Channel 1 V = 12V, V = 1.0V, I = 0A to 5A See Figure 5 IN OUT1 STEP Load Transient of Channel 2 V = 12V, V = 1.2V, I = 0A to 5A See Figure 6 IN OUT2 STEP Load Transient of Channel 3 V = 12V, V = 3.3V, I = 0A to 5A See Figure 7 IN OUT3 STEP Quick s p D Demonstration circuit DC1905A is an easy way to evalu- 5. (Optional) For optional load transient test, apply an ate the performance of the LTM4633EY. Please refer to adjustable pulse signal between IOSTEP CLK and GND Figure 1 for proper measurement equipment setup and test points. The pulse amplitude sets the load step cur- follow the procedure below: rent amplitude. Keep the pulse width short (<1ms) and pulse duty cycle low (<5%) to limit the thermal stress 1. Place jumpers in the following positions for a typical on the load transient circuit. Switch the jumper resistors application: R30, R31 or R34 (on the backside of boards) to apply RUN1 RUN2 RUN3 MODE load transient on channel 1, channel 2, or channel 3 ON ON ON CCM respectively. 6. (Optional) LTM4633 can be synchronized to an external 2. With power off, connect the input power supply, loads clock signal. Place the JP4 jumper on EXT CLK and and meters as shown in Figure 1. Preset the load to 0A apply a clock signal (0V to 5V, square wave) on the and V supply to 12V. CLKIN test point. IN 3. Turn on the power supply at the input. The output 7. (Optional) The outputs of LTM4633 can track another voltage of channel 1 should be 1.0V 1.5% (0.985V supply. If tracking external voltage is selected, the cor- to 1.015V). The output voltage of channel 2 should be responding test points, TRACK1, TRACK2, and TRACK3, 1.2V 1.5% (1.182V to 1.218V). The output voltage of need to be connected to a valid voltage signal. channel 3 should be 3.3V 1.5% (3.25V to 3.349V). 8. (Optional) Channel 1 and 2 can be connected in paral- 4. Vary the input voltage from 4.7V to 16V and adjust the lel for a 20A polyphase operation on DC1905A. Install load current of each channel from 0A to 10A. Observe 0 resistors on R32, R33, R35, R36 and remove R15. the output voltage regulation, ripple voltage, efficiency, Output voltage is set by R4 based on equation V = OUT and other parameters. 0.8V (1 + 60.4k/2/R4). dc1905af 2 ure roce tart ummary erformance