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 40V to 57V input-voltage, current-mode PWM converters and provides frequency foldback. 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.

Pasadena interfaces to powered Ethernet with an RJ-45 connector (J1). A second RJ-45 (J3) is present to read data out of the system. The MAX5969B provides the complete interface to the Ethernet connection, providing detection signature, classification signature, inrush current control, and 2-event classification. The MAX5969B also interfaces with a wall adaptor input, detecting the wall adaptor input and switching between power sources. When present, a wall adaptor power source always takes precedence over the power-sourcing equipment (PSE) power, allowing the wall adaptor to power the reference design.

Applications:

• Security cameras
• Wireless access points
• Point of sale terminals