PoE ICs Meet IoT Demands

Silicon Labs’ Power over Ethernet (PoE) Powered Device (PD) families target a wide range of Internet of Things (IoT) applications. The Si3406x and Si3404 families include all necessary high-voltage discrete components on a single PD chip. The new PD ICs support IEEE 802.3 at PoE+ power capabilities, flexible power conversion options exceeding 90 percent efficiency, robust sleep/wake/LED support modes and superior EMI immunity. These capabilities help developers reduce system cost and time to market for high-power, high-efficiency PoE PD applications.


The Si3406x ICs integrate all power management and control functions required for a PoE+ PD application, converting the high voltage supplied over a 10/100/1000BASE-T Ethernet connection to a regulated, low-voltage output supply. The optimized architecture minimizes printed circuit board (PCB) footprint and external BOM cost by enabling the use of economical external components while maintaining high performance.


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Complementing the Si3406x family, the Si3404 IC offers cost-effective, 802.3 Type 1 compliant support for lower power 15 W PoE PD applications. The Si3404 includes all interface and control functions required for low-power PD applications in a very small footprint.


The Si3406x ICs integrate diode bridges and a transient surge suppressor, enabling direct connection to an Ethernet RJ-45 connector. The regulator's switching frequency is tunable with a simple external resistor value to avoid unwanted harmonics. An integrated synchronous driver can control a secondary side field effect transistor (FET) to improve power conversion efficiency. Connection to a PSE switch is maintained during sleep mode by an automated maintain-power-signature (MPS) feature.


The Si3406x family's current-mode-controlled switching regulator supports multiple isolated and non-isolated power supply topologies. The regulator is complemented by an integrated power switching FET. This flexibility, along with Silicon Labs' comprehensive PoE PD reference designs, makes it easier for developers to deploy critical power supply subsystems.


Samples and production quantities of the Si3406x ICs are available now in 5 mm x 5 mm QFN packages, and the Si3404 device is available in a 4 mm x 4 mm QFN package. Si3406x product pricing in 10,000-unit quantities begins at $1.34 and the Si3404 is priced at $1.02 each/10,000. To help developers reduce development time and cost, Silicon Labs offers a range of isolated and non-isolated Class 2-4 evaluation kits for Si3406x and Si3404 devices with prices starting at $79. More information, specs, and datasheets await the curious.