The Si3406x family integrates all power management and control functions required in a Power-over-Ethernet Plus (PoE+) powered device (PD) application. These devices convert the high voltage supplied over the 10/100/1000BASE-T Ethernet connection to a regulated, low-voltage output supply. The optimized architecture of this device family minimizes the solution footprint and external BOM cost and enables the use of low-cost external components while maintaining high performance. The Si3406x family integrates the required diode bridges and transient surge suppressor, thus enabling direct connection of the IC to the Ethernet RJ-45 connector. The switching power FET and all associated functions are also integrated. The integrated, current mode controlled switching regulator supports isolated or non-isolated flyback and buck converter topologies. The switching frequency for the regulator is tunable with a simple external resistor value to help avoid unwanted harmonics for better emissions control. A synchronous driver is provided to optionally drive a secondary side FET to improve efficiency of power conversion. Connection to the PSE switch is maintained during sleep by an optional automated maintain-power-signature (MPS) signal.
These devices fully support the IEEE 802.3at specification for the cases of single or two event classification. Standard external resistors provide the proper IEEE 802.3 signatures for the detection function and programming of the classification mode, and internal startup circuits ensure well-controlled soft-start initial operation of both the hotswap switch and the voltage regulator.
The Si34061 and Si34062 add main transformer bias winding support for ultra-high-efficiency operation.
The Si34062 includes support for sleep modes with wake function, as well as LED drive capability. These features can be utilized to minimize standby current, control sleep and wake states, and provide application status information using an LED.
SKYWORKS SI3406-A-GM