The Akros Silicon AS1138 is a single-chip, highly-integrated CMOS solution for Power over Ethernet (PoE) powered devices requiring input power of up to 30 W. Applications include Voice over IP (VoIP) phones, wireless LAN access points, security cameras, WiMax terminals, Point of Sales terminals, RFID readers, Thin Clients, and Notebook computers.

The AS1138 integrates input surge protection, a digital PD controller, and a low-emission DC-DC controller. The AS1138 implements all the physical layer Powered Device (PD) functionality as required by the IEEE® 802.3af-2005 and IEEE® 802.3at standards. This includes 2-event classification, Type-2 PSE detection indicator (ATDET) in addition to PD detection, under-voltage lockout, and hot-swap FET integration.

The AS1138 has been architected and designed to address both EMI emission concerns and surge/over-voltage protection in PoE applications. The AS1138 implements many design features that minimizes transmission of system common-mode noise on to the UTP. On-chip integration of surge protection provides faster response to surge events and limits stray surge current from passing through sensitive circuits, such as the Ethernet PHY device. The device is designed to provide a safe low-impedance discharge path directly back to the earth ground, resulting in superior reliability and circuit protection.