I am looking for a PoE Ethernet chip that I can incorporate in a design I plan on using along with some of the Arduino features. I would prefer to implement a standalone mcu for the Ethernet device capable of providing Ethernet. All possible solutions must support PoE to power the Micro. I do not plan on buying an Arduino nor do I want any shields per se. I am looking for a PoE Ethernet chip that would work well with the Arduino firmware and micro controller. A chip that I can incorporate into my own custom Arduino board.

I would also be interested in any AVR chips which provide the same capabilities (pin wise) as the Arduino ATMega168/etc that has Ethernet built on board.

My devel platform would be AVRStudio or something like it with a Jtag ICE MKII. I do not have the ability to use PIC as I do not have a programmer, the software, nor the cash to invest in another platform.

Thx in advance for your help.

Edit: Andrew noted that I should post more info. First of all Andrew: I have not looked at the MFGs you mentioned. I will do so now.

I would like to place a few Freeduino type setups around the house to do various home automation tasks. My home is already wired with Cat6 and I plan on plugging certain network drops into a 10/100 8 port Linksys POE switch. I would like to provide network and power to each device without having to hack the network cables. I have verified that the switch conforms to the 802.3af standard.

I would like to create each board to solely pull power off of the PoE lines to provide sensor and relay capability (relays would be SSR - GA8-6D05 from Crouzet which requires 3-32VDC for the relay.

I would expect the PoE chip to deliver either full PoE voltage or be nice enough to drop it down to 7-12VDC. If needed, I can add a 7805 or appropriate chip to ensure voltage regulation. In the end, my micro would need 5V + 3V DC regulated @ 1A.

Hope this answers anything my original post left out.


4 Answers 4


You really haven't given us any actual information to help you with other than you don't want an Arduino shield solution. What kind of power supply do you need? How many voltages, and at what current levels? Are you just powering the AVR? Do you need galvanic isolation?

I have successfully used National's LM5071 PoE PD controller in one of my designs. Depending on how you want to hook it up, it'll give you full galvanic isolation and multiple output voltages. My particular setup gives me 3.3V at 2A and a separately-isolated 5V at 1A. I "slave" an LTC3523 off the 3.3V to give me 1.8V and 5V supplies that aren't isolated from the main 3.3V supply.

Many companies offer PoE PD controllers. National, Maxim, Linear Tech, TI... Have you done any poking through their websites to see what's out there so you can narrow down your search?

EDIT now that I have more information from the edited question. :-)

TI's TPS2370 looks like a perfect fit. It's an 8-pin SOIC device that takes care of the 802.3af spec part and you can drive pretty much ANY regulator off of that. So a really simple supply would consist of the TPS2370 and something like the BD9001 (personally I like Linear's LT1676 but I don't think it has a high enough input voltage spec for PoE) from the previous answer. Two 8 pin SOIC devices, a handful of passives and a small inductor would get you what you're after.

  • \$\begingroup\$ The LM5071 sounds like it would be a great choice for the circuit I would like to build. I would like to find a chip that might support both 802.3af and 802.3at if possible. I will check out the sites you recommended. I also modified my post with additional details. \$\endgroup\$ Commented Oct 21, 2010 at 0:43
  • \$\begingroup\$ TPS2370/LT1676: Very nice. Let me play around with that for a few hours and see if it fits what I am looking for. Thx for the help. \$\endgroup\$ Commented Oct 22, 2010 at 4:26
  • \$\begingroup\$ You may want to look into the Silvertel Ag9712-BR2/FL combined solution. \$\endgroup\$ Commented Oct 9, 2019 at 13:10
  • \$\begingroup\$ Check the opensource circuit diagrams for the Intel Galielo 2, it has PoE and only requires the Silvertel Ag9712-BR2/FL to make it completely function. \$\endgroup\$ Commented Oct 10, 2019 at 3:20

The Olimex PIC Micro Web board seems to support POE with a BD9001F switching regulator.

Olimex PIC Micro Web schematic

This looks like a low cost way of adding PoE to a device.

  • \$\begingroup\$ That chip looks very nice and capable. Unfortunately, I only have the devel platform and programmer for AVR atm. As I don't have a lot of money to invest in tools and software, I would have to pass this nice piece of hardware up. \$\endgroup\$ Commented Oct 20, 2010 at 23:10
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    \$\begingroup\$ Be careful -- this is not an actual PoE PD (powered device) -- it does not conform to the 802.3af spec and if you're using a 802.3af compliant PoE switch it will not supply voltage to this device. \$\endgroup\$
    – akohlsmith
    Commented Oct 20, 2010 at 23:53

The Freetronics EtherTen web pages claims "Power-over-Ethernet support, both cheapie DIY or full 802.3af standards-compliant."

It appears to be a "open hardware" design, implying you are welcome to download the design files and incorporate as much as you want into your own custom boards.

From the schematic, it appears to use the WIZnet W5100 single-IC Ethernet interface. Circuit Cellar issue 208 (November 2007) has an article by Fred Eady titled "iEthernet Bootcamp - Get Started with the W5100".

  • \$\begingroup\$ actually it required an additional PoE "sub" module to implement 802.3af, which has an actual transformer on it to handle the 48v, plus the other smarts required. freetronics.com.au/products/… \$\endgroup\$ Commented Oct 9, 2019 at 1:52

Looks like you've got a good answer already, but I thought I'd point out this shield (yes, a shield!) from Freetronics: Freetronics — Ethernet Shield with PoE. His design files are linked to at the bottom of the page. Those might provide some insight into making your own design.

  • \$\begingroup\$ The Freetronics shield is the same kind of design as the BD9001 one in one of the earlier answers; it is NOT 802.3af compliant, and even states such on the web site linked by you. If you want it to be compliant you need to add a daughterboard that is not yet available. \$\endgroup\$
    – akohlsmith
    Commented Oct 21, 2010 at 13:06
  • \$\begingroup\$ In my design 802.3af would be a requirement. \$\endgroup\$ Commented Oct 22, 2010 at 0:30

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