Thursday, September 27, 2007

STMicroelectronics Launches PoE Controllers for Networked Devices

STMicroelectronics announced two new families of Power-over-Ethernet (PoE) interface controllers. All devices in the families are compliant with the IEEE 802.3af specification for powered devices (PD), which provide all the control functions needed to enable a PD to request and draw power from an Ethernet network via a power source.

STMicroelectronics designers could use these new controllers to eliminate the 110/220V AC power lines to many wired LAN devices such as VoIP phones and security cameras. Other applications benefiting from PoE include webcams, WLAN access points, point of sale (POS) terminals and RFID readers.

Each device consists of two main sections: the IEEE802.3af-compliant interface to the PoE-powered RJ-45 wall socket, which includes basic PD Detection and Classification functions; and the Hot Swap Controller (HSC), which protects the PD during insertion, operation and power withdrawal. The controllers integrate a high-voltage power MOSFET (low-side switch), with low RDS ON, and with the capability to accept transients as high as 100V. The 'hot swap' features include functions such as inrush current limiting, undervoltage lockout (UVLO), and thermal overload protection.