Demonstration circuit 2922A-A and 2922A-B are dual step-down DC/DC converters featuring the LTC7802 or LTC7802-3.3 PWM controllers. Both controller IC’s used on these demo boards are 40V Low IQ, Dual, 2-Phase Synchronous Step-Down Controllers with Spread Spectrum. And both demo boards operate over a 5V to 36V input voltage range and provide a 3.3V at 20A and 5V at 15A outputs.
The DC2922A-A uses the LTC7802 and has a resistor divider network to set the 3.3V output. The DC2922A-B uses the LTC7802-3.3 and has a fixed 3.3V output that does not require the resistor divider network.
Some of the key features of both boards include a FREQUENCY jumper for spread-spectrum or external clock option, and EXTVCC jumper for VOUT2, EXTVCC, or input derived VCC, a MODE jumper that allows the converter to run in FCM, pulse-skipping, or Burst Mode® operation and PGOOD signals for each output.
The two channels can be paralleled for higher output current. See the respective data sheets for more information on setting-up the board for paralleling both outputs. The LTC7802 and LTC7802-3.3 data sheets give a complete description of these devices, their operation and application information, and must be read in conjunction with the DC2922A demo manual prior to working on or modifying these demo circuits.
