WS3204

WS3204 is a device that combines a Power over Ethernet (PoE) Powered Device (PD) interface with a current-mode DC-to-DC controller. The PoE interface supports the IEEE 802.3at standard and supports a number of input voltage ORing options, including highest voltage, external adapter reference, and PoE priority selection, allowing designers to determine which power source bears the load under all conditions. The PoE interface features dual-event, physical-layer classification required for compatibility with high-power midspan PSEs (compliant with IEEE 802.3at), a signature detection pin to force PoE power shutdown, and a single resistor to set the classification to any class within a defined range. The DC/DC controller features two complementary gate drivers with programmable dead time, simplifying the design of active-clamp forward converters and high-efficiency flyback topologies with secondary synchronous rectification; the second gate driver can be disabled for single-MOSFET topologies. The controller also features internal soft-start, bootstrap startup source, current-mode compensation, and a maximum duty cycle of 78%. A programmable and synchronizable oscillator allows design optimization for efficiency and simplifies controller use, while precise programmable blanking with a one-cycle default period simplifies the design balance of common current-sense filters.

Applications

• IEEE 802.3at-compliant Powered Devices (PD)
• Video and VoIP phones
• RFID readers
• Wireless access points
• Surveillance cameras

Key features

• Optimized DC-to-DC control for isolated converters
• High-efficiency topology support
• Complete PoE interface
• Enhanced classification with IEEE 802.3at compliance and status flags
• Adapter ORing support
• Programmable frequency setting with synchronization
• Robust 85V, 0.4Ω hot-swap MOSFET
• Operating junction temperature range: -40°C to 125°C
• Industry-standard TSSOP20-F package