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ICs Add 90-W PoE to 5G Small Cells

April 14, 2020
Three new PoE devices bring power to IoT nodes with flexibility and a high degree of integration.

The cost and complexity of adding 90-W Power over Ethernet (PoE) to power-sourcing equipment (PSE) and powered devices (PDs) has decreased thanks to the launch of Silicon Labs’ portfolio of PoE devices. The devices comply with the IEEE 802.3bt standard, which more than doubles standard PoE power and expands the capabilities of wireless access points and IoT wireless gateways. With their higher power capabilities, the portfolio’s devices help make PoE-powered 5G small cells and digital buildings a practical reality.

The 802.3bt PoE portfolio delivers high power, extensive integration, and advanced features to help developers simplify their system designs while meeting stringent power, size and cost budgets. Spanning both ends of the Ethernet cable from 15 W to 90 W, the devices give developers flexible options for a wide range of PSE and PD applications.

The 802.3bt portfolio includes three new PSE and PD products: 

·        The Si3471 PSE controller is said to be the industry’s first fully autonomous, 90-W, single-port 802.3bt-compliant power-sourcing device. The Si3471 makes it easy to add 90 W power to single-port midspans or “injectors,” and automatically manages all nuances associated with the 802.3bt standard. It requires no external host MCUs, firmware downloads, or software programming, and is simple to configure using three digital I/O pins. The small 38-pin, 5 mm x 7 mm QFN package and simple BOM help reduce system cost and complexity. Si3471 samples and production quantities are available now. Si3471 pricing starts at $1.97 in 10,000-unit quantities. The Si3471 evaluation board (EVB) is priced at $105.

·         The Si3474 quad Ethernet-port PSE controller powers up to four 90-W, 802.3bt PoE ports or up to eight 30-W 802.3at/af PoE ports, providing a versatile controller for industrial and commercial Ethernet switches and security recording equipment. The Si3474 can be operated in autonomous mode with full power on each port or in hosted mode, enabling developers to manage power through an I2C interface with a full-featured register map. The Si3474 is available in a 56-pin, 8 mm x 8 mm package with an industry-standard pinout. Si3474 samples and EVBs are planned to be available in April 2020. Si3474 pricing starts at $3.33 in 10,000-unit quantities. The Si3474 EVB is priced at $199.

·         The Si34071 single-chip PD device combines an 802.3bt interface with an integrated, high-efficiency dc-dc converter capable of achieving more than 90% end-to-end efficiency. The Si34071 includes a simple, 9600-baud UART interface to the system MCU. The Si34071 delivers high power for 5G small cells, wireless access points, and IoT gateways. A companion to the Si3471 PSE controller, the Si34071 comes in a small 32-pin, 5 mm x 5 mm QFN package. Si34071 samples and EVBs are planned to be available in April 2020. Si34071 pricing starts at $2.13 in 10,000-unit quantities. The Si34071 71 W forward converter EVB is priced at $119.

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