MAXREFDES31#: 5V @ 3A, 3.3V @ 1.8A, 40 ~ 57V in, POE

Pasadena (MAXREFDES31#) is a highly efficient, flyback, 3.3V and 5V Class 4 powered device (PD) with a 40V to 57V auxiliary input. The design features the MAX5969B as the controller. The MAX5974A controls current-mode PWM converters and provides frequency fold-back for both the auxiliary input and power-over-Ethernet (PoE) applications. The design is a high-performance, compact, IEEE 802.3af/at compliant, cost-efficient solution for a PD with power level up to Class 4. The design can also support the auxiliary-input to provide approximately 21W output power.

The Pasadena (MAXREFDES31#) reference design features the MAX5969B and MAX5974A. The MAX5969B controller is fully compliant with the IEEE 802.3af/at standard in a power-over-Ethernet (PoE) system. The device can also be powered from a wall adapter (WAD). The WAD operates with higher priority than PoE, which is controlled by the MAX5969B. The MAX5974A controls a 40V to 57V input-voltage, current-mode PWM converters and provides frequency fold-back. Using these devices, this reference design is IEEE 802.3af/at compliant. It is also a high-performance, compact, and cost-effective solution for a PD supporting power up to Class 4 power level.