WS3203

WS3203 is a device that combines a Power over Ethernet (PoE) Powered Device (PD) interface with a current-mode DC/DC controller. The PoE interface supports the IEEE 802.3af standard (as a 13W, Class 1 PD); the requirements for an IEEE 802.3af Class 1 device are a superset of IEEE 802.3-2008 (originally IEEE 802.3af). WS3203 supports multiple input voltage ORing options, including highest voltage, external adapter reference, and PoE priority selection, enabling designers to determine which power source assumes the load under corresponding conditions. The PoE interface features an external detection pin that can be used to disable the internal hot-swap MOSFET to shut down PoE functionality; a single resistor can set the classification to any defined class. The DC/DC controller features internal soft-start, bootstrap startup source, current-mode compensation, and a maximum duty cycle of 78%. A programmable and synchronizable oscillator optimizes designs for efficiency and simplifies controller usage, while precision-programmable blanking with a default period simplifies the common current-sense filter balance design.

Applications

• IEEE 802.3af-compliant Powered Devices
• Video and VoIP phones
• RFID readers
• Wireless access points
• Surveillance cameras

Key features

• Optimized for isolated converter DC-to-DC control
• High-efficiency topology support
• Complete PoE interface
• IEEE 802.3af compliant
• Adapter ORing support
• Programmable frequency with synchronization
• Robust 85V, 0.5Ω hot-swap MOSFET
• -40°C to 125°C operating junction temperature range
• Industry-standard TSSOP-14 package