Advanced Chipsets Bring Smart-Building Applications


The chipset saves space, enhances reliability, and cuts time to market for next-generation connectivity equipment including 5G “small cells,” WLAN access points, switches, and routers

A new chipset from STMicroelectronics lets users quickly build reliable and space-efficient Powered Devices (PDs) to take advantage of the latest IEEE 802.3bt Power-over-Ethernet (PoE) specification.

The PM8804 and PM8805 provide the PoE-converter circuitry for PDs up to class-8, which defines a usable power budget of 71 Watts. ST’s new PoE chipset also targets smart-building and smart-office applications such as IP cameras, access-control systems, display panels, lighting, curtain or shutter controllers, video-call systems, IP phones, and tabletop consoles.


The PM8804 implements a complete PWM controller for a 48V isolated flyback or forward converter, including dual low-side gate drivers for high-efficiency forward active-clamp topologies. The operating frequency allows the use of small external filter and decoupling components for high power density. The PM8804 helps save on board space and bill of materials.

Key Features (PM8804)

  • A high-voltage start up regulator with 20mA output capability.
  • Operating frequency is selectable up to 1MHz.

The PM8805 companion chip contains two active bridges, a charge pump for driving high-side MOSFETs, a hot-swap FET, and the IEEE 802.3bt compliant interface. Integrating the active bridges saves the real-estate otherwise occupied by eight discrete MOSFETs and their driving circuitry.

Key Features (PM8805)

  • Generates a Power-good signal for enabling the PM8804 and other circuitry such as an LED driver.
  • Supports Maintain Power Signature (MPS) current control that allows the PD to enter power-saving standby without being disconnected.


Both devices are in production now. The PM8804 is packaged as a 3mm x 3mm, 0.5mm-pitch VFQFPN-16, and priced at US$ 0.60 for orders of 1000 pieces. The PM8805 in 8mm x 8mm thermally enhanced VFQFPN-43 featuring exposed pads is US$ 4.50.

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For more on PM8804, visit here

For more on PM8805, visit here



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