SI3402-B-GMR

The Skyworks Solutions SI3402-B-GMR is a highly integrated IC designed for Power-over-Ethernet (PoE) powered device (PD) applications. It efficiently converts the high voltage supplied over an Ethernet connection into a regulated, low-voltage output. This device minimizes solution footprint and reduces external component costs while maintaining high performance.

The Si3402-B integrates essential components like diode bridges and a transient surge suppressor, allowing direct connection to an Ethernet RJ-45 connector. It also includes an integrated switching power FET and controller, supporting both isolated (flyback) and non-isolated (buck) converter topologies. The IC complies with IEEE 802.3 Type 1 standards (Class 3 and below) and features programmable classification circuitry.

Key features include comprehensive protection mechanisms such as transient overvoltage protection, undervoltage lockout, early power-loss indication, thermal shutdown, and foldback current limiting. The Si3402-B is available in a low-profile, 20-pin, 5 x 5 mm QFN package, making it suitable for compact designs. It is a pin-compatible replacement for the obsolete Si3402-A, though some component value changes may be required for PCB layouts.

This PoE controller is ideal for applications like Voice over IP telephones, wireless access points, security cameras, point-of-sale terminals, and other network devices requiring power delivery over Ethernet.