Microchip Lays Out Vision for Power Over Ethernet in Building Automation with New Eight-Port Switch

May 23, 2019 by Gary Elinoff

What's a digital ceiling, anyway? Microchip announces new PoE switch for Ethernet building automation design.

What's a digital ceiling, anyway? Microchip announces new PoE switch for Ethernet building automation design.

This week, Microchip announced through its subsidiary Microsemi an eight-port device that provides guaranteed power of 60 W per port for all eight ports simultaneously: the PDS-408G.

The 480-watt fanless switch is designed for digital lighting applications and will connect separate systems such as lighting, sensors, HVAC, and Wi-Fi access points over a single switch.


PoE Building Automation

Building automation is a term that refers to automation that is specific to the inner workings of a building. In general, this will often refer to commercial-grade buildings or compounds, but the concept extends both directions into both smaller systems like smart homes and enormous systems like smart cities. You can check out this roundup on building automation if you'd like a bird's-eye view of recent happenings related to this application.

Microchip, among other large players in the field, are looking closely at PoE as the solution for more connected buildings.

Interestingly, the application that Microchip has in mind for this switch is the "Microchip Digital Ceiling":


All images used courtesy of Microchip


The concept is for this switch to bring power and data to various Ethernet terminals for connected lighting, power systems, security, etc. 

In addition to providing a guaranteed 60 W to each port, the PDS-408G can also deliver 90 W to any one port.


Plenum-Rated, Fanless Design

A plenum space in a building is an area with a specified amount of airflow. It’s a great place to put power-bearing and/or communications cables. That’s because no matter how efficient the cabling system is, some heat will be generated.

The PDS-408G, combined with proper cabling, will not overwhelm the heat transfer capacity of a plenum space.


A closer look at the PDS-408-G. Image from Microsemi


The PDS-408G’s design is fanless, which can be an important spec for applications that require quiet operation. The lack of fans also helps reduce maintenance needs as there are fewer moving parts to malfunction.

Power Over Ethernet

The Ethernet can be thought of as a kind of local internet. It’s used for communication between local networks of devices, providing internet and data connections within homes and offices. For the curious, you can check out a project using Microchip's Ethernet of Everything (or EoE) kit from our comedy series, MIT-i.

Power over Ethernet means that the same cable that carries digital information to a remote device also delivers its electrical power. The obvious analogy is a USB cable, which can charge a smartphone and also communicate with it.

This means that there is only one cable to run, not two. This saves time, money, and simplifies the installation process.

“Demand for Power over Ethernet in connected lighting systems has accelerated, and our new PoE switch is designed specifically for the needs of these applications,” said Rich Simoncic, senior vice president of Microchip’s Analog, Discrete and Power business unit. “The PDS-408G continues Microchip’s leadership in PoE technology, providing an IEEE 802.3bt-compliant solution that provides almost six times the amount of power than the original PoE standard.”

The IEEE 802.3bt Power over Ethernet (PoE) Standard 

To prevent an electronic Tower of Babel where each manufacturer’s systems would be incompatible to those of others, the IEEE wisely stepped in and established a standard, IEEE 802.3. The IEEE 802.3 standard was updated last month to ensure the standard will be able to serve the growing IoT and the data centers that spring up to serve it. 

The advent of 5G will make power over Ethernet an even more pressing issue. We discussed some of these issues in last month's article on STMicroelectronics' new PoE chipset, the PM8804 and PM8805.

At the Other End of the Cable: The Ethernet of Everything

As Microchip puts it, “Whether called Internet of Things (IoT), Industrial IoT, or Industrial Ethernet—any “thing” can now be connected and controlled—garage openers, home appliances, HVAC systems, lighting and an endless array of other common products.”

To that end, the company provides a wide range of products to facilitate the “Ethernet of Everything”.


The Ethernet of Everything


For designers, the "EoE" looks like a series of resources, including hardware like the PDS-408G, an EoE-supported portfolio of MCUs, accompanying firmware, and a slew of app notes and downloadable board design files. If you choose to try one of these board designs for yourself, please let us know about your experiences in the comments below.

Other Manufacturers

To many, PoE is an obvious choice when connecting remote (or not so remote) devices over the Ethernet to a controller. It’s not surprising that many manufacturers have entered the fray. However, most are only slowly adapting to the latest version of the 802.3 standard.

A couple of players you may want to be aware of include:

  • The PU842G series from Yoda are eight-port PoE switches. Various versions of the series adhere to combinations of the new IEEE 802.3bt standard and the older IEEE 802.3at and IEEE 802.3af standards.
  • The 4000 Series from Phoenix Contact adhere to IEEE 802.3bt. They are touted as being suitable to power and communicate with devices such as high power cameras over Ethernet cables.

If we've missed anybody, let us know and we'll update this section.



Working with PoE in a current design? Tell us about it in the comments below.