DC455A Analog Devices

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC455 HIGH EFFICIENCY DUAL PHASE 2-OUTPUT POWER SUPPLY LTC3707EGN DESCRIPTION Demonstration circuit DC455 is a dual output, step- 5V with loads up to 5A and output 2 is 3.3V with loads down, synchronous buck converter featuring the 150kHz up to 5A. Design files for this circuit board are avail- to 300kHz LTC3707EGN controller. This controller can able. Call the LTC factory. operate with input voltages from 7V to 21V. Output 1 is Table 1. Performance Summary PARAMETER CONDITION VALUE Minimum Input Voltage 7V Maximum Input Voltage 21V V V = 7V to 21V, I = 0A to 5A 5V% OUT1 IN OUT1 V V = 7V to 24V, I = 0A to 5A 3.3V% OUT2 IN OUT1 Switching Frequency Jumper selectable 150kHz300kHz QUICK START PROCEDURE Demonstration circuit DC455 is easy to set up to 4. Switch on the Vout1 channel by removing the RUN1 evaluate the performance of the LTC3707EGN. Refer to jumper. Vout1 should be 5V 0.1V. Figure 1 for proper measurement equipment setup and 5. Increase the load current of Vout1 to 5A. At 7V in- follow the procedure below: put voltage, the input current should be less than NOTE: When measuring the input or output voltage rip- 4A. Slowly increase the input voltage up to 21V. At ple, care must be taken to avoid a long ground lead on 21V input voltage, the input current should be less the oscilloscope probe. Measure the input or output than 1.5A. voltage ripple by touching the probe tip directly across 6. Decrease Vout1 load current to 0A. Reduce the in- the Vin or Vout and GND terminals. See Figure 2 for put voltage to 7V. Switch on the Vout2 channel by proper scope probe technique. removing the RUN2 jumper. The output voltage of 1. With the power off, place the jumpers as shown in Vout2 should be 3.3V 0.05V. Figure 1. 7. Increase the load current of Vout2 to 5A. At 7V in- 2. Connect the desired loads to Vout1 and Vout2. The put, the input current should be less than 3A. loads can be as high as 5A for Vout1 and 5A for Slowly increase the input voltage to 21V. At 21V in- Vout2. Pre-set the load current to 0A. put, the input current should be less than 1.0A. 3. Set Vin to 7V (recommended). The rated input volt- age range is 7V to 21V. 1 GND VIN QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC455 HIGH EFFICIENCY DUAL PHASE 2-OUTPUT POWER SUPPLY LOAD + + + LOAD Figure 2. Scope Probe Placement for Figure 1. Proper Measurement Equipment Setup Measuring Input or Output Ripple 2 + + + + + +