Single Port PoE Interface With Integrated DC-DC Controller from Silicon Labs

Unlike competing single-port solutions providing only a PSE interface, the Si3460 integrates a dc-dc digital power controller to cost effectively generate a negative 48V PSE supply, ensuring safety extra low voltage (SELV) compatibility with legacy telephony ports within the system. The Si3460 reduces the total PSE solution cost to less than US$2.00 and preserves the use of low-cost, 12V power supply adapters and typical point-of-load (POL) dc-dc converters. The Si3460-EVB reference design, which includes all the recommended external components for a complete single-port PSE design, also provides IEEE 802.3af-compliant detection, classification and disconnect functionality.

The Si3460 controller provides extensive protection such as inrush current control, input under voltage lockout (UVLO), short circuit protection and current limiting to ensure robust, fail-safe operation during all operating conditions. The Si3460 also supports Fast (10/100 Mbps) and Gigabit Ethernet endpoints and midspans and is pin configurable to supply maximum power (15.4W, Class 0) PSEs, or limit power to IEEE class levels one through three.

“The Si3460 uniquely solves the two main challenges facing PSE systems designers: implementing a fully compliant IEEE 802.3 PSE interface and easily and safely generating the negative 48V PSE power supply from an existing low-voltage supply,” said Dave Bresemann, vice president of Silicon Labs. “In combination with the Si3400/01 controller for PDs, Silicon Labs provides end-to-end solutions for PoE.”