DAK-86: POE, 6.6 W, 3.3V @ 2.0A, 33 ~ 57 V in

A flyback topology was used to minimize circuit board size, parts count and cost. This topology also provides excellent operating efficiency across the input voltage range.

The DPA423G IC implements PWM control of the internal power MOSFET and initiates a soft start-up function when it first powers up. The IC also monitors die temperature as part of its over-temperature protection function and also monitors the input voltage as part of its under-voltage detection and overvoltage shutdown functions.

The integrated 220 V MOSFET provides excellent switching characteristics at the selected 400 kHz operating frequency. The MOSFET and controller consume very little power, giving good efficiency across the entire input voltage operating range.