Si3402 and Si3404 PoE Powered Devices are the most highly-integrated, IEEE 802.3at Type 1-compliant, PoE PD interface and pulse-width-modulated (PWM) switching regulator devices in the industry. Si3402 and Si3404 products set a new bar for device integration, lowest overall BOM cost, efficiency and reliability and enable quick addition of PoE functionality to Ethernet applications. When included in the design of a PoE-enabled system, such as a wireless access point or VoIP phone, Si3402 and Si3404 devices convert the high voltage (typically ±48 V) supplied over Ethernet copper UTP cabling into a regulated, low-voltage dc supply. Si3402 and Si3404 devices combine all the required IEEE 802.3 at Type 1 detection, classification and hot swap interfaces with a complete, high efficiency, PWM switching regulator.
Si3402-B is a pin-compatible replacement for the end-of-life Si3402-A. Existing customer products based on Si3402-A EVB reference designs can be readily re-used with minimal change to a few on-board components. Si3402 is a strong legacy device with long-term support, is available in a 5mm x 5mm QFN package and includes input diode bridges on chip. The newer Si3404 offers additional features in a compact 4mm x 4mm QFN package and does not include input diode bridges on-chip.