Eliminating external power supplies for VoIP phones, WLAN access points, and security cameras, the company's two families of Power-over-Ethernet (PoE) interface controllers are fully compliant with the IEEE 802.3af specification for powered devices.
Eliminating external power supplies for VoIP phones, WLAN access points, and security cameras, the company's two families of Power-over-Ethernet (PoE) interface controllers are fully compliant with the IEEE 802.3af specification for powered devices. Each device consists of two sections: the IEEE802.3af-compliant interface to the PoE-powered RJ-45 wall socket and the hot-swap controller. They integrate a power MOSFET handling transients up to 100V. Hot swap features include inrush-current limiting, under-voltage lockout, and thermal-overload protection. The STHS2375, STHS2376, STHS2377, STHS4257A/L, and STHS4257A1/L1 are available with either latched operation or automatic retry after fault conditions. The STHS4257 integrates a 25-kΩ signature resistor with signature-disable function, while the STHS237x requires an external resistor. The STHS237x family also offers devices for all UVLO limit configurations: IEEE compliant (STHS2375), programmable (STHS2376), and for legacy systems (STHS2377). The STHS4257A1/L1 includes a dual-level current-limit circuit, which allows it to interface with legacy PoE systems while maintaining compatibility with the IEEE 802.3af specification. Both families are available now with prices ranging from $1.01 to $1.35 each/1,000. STMICROELECTRONICS, Lexington, MA. (888) 787-3550.
