W5100 ARP, PING and connection problems



I have a design with the W5100. The W5100 works without any problems in about 1000 units. But the latest production of 100 units with the W5100 - bought start of 2014 - has a failure in about 60% of the boards. If connected to a pc or a switch the link-led and the speed led behave like expected. Link is stable, but the W5100 is not responding to ARP-requests and therfore also not responding to a ping or a connection request. I can read and write the registers. I checked all connections, supply, gnd, reset, mode etc. Nothing wrong with the boards and the identical software is working on 40% of the boards. Does anybody know, if there are any changes applied to the W5100 late 2013 to start 2014? Is there any bad charge? It seems like the TCP/IP engine is not working. My last charge was bought in mid of 2013…

Thank you and regards



Do you have any changing reside W5100?
Any part, any schematic, any firmware and any test environment is not changed?



As far as I know W5100 was not changed anything since 2010.
I mean we produce it as the same mask, FAB , test sequence, Package house and so on.
Anyway I will check the procuction flow again from our foundry FAB.
So I’d like to know the W5100 data code which is on the package about bad samples.




thank you for the help. No, nothing was changed: Same boards, firmware, test environment. The part code from the problematic parts are POFK7-010-1244 (mayby PO P K7-010-1244, it is a little bit hard to read). After rework with PC202-010-1228 (from an old buy) everything is working fine. As I said , it looks like the TCP/IP engine is not working. Registers are setup correctly. I did a basic test with only setup the IP and subnet (read back after setup is ok). As I understand in this state the W5100 should reply to a ARP request and PING. Link is stable, sometime it flashes, when a packet is on the wire, but not responding to an ARP or PING.




Where did you buy W5100 ?
You mean Data code 1244 does not work well, but Data code 1228 works well.
Am I right ?
Data code 1244 means those samples were produced 44th weeks in 2012.
I will check Data code 1244 samples and get back to you soon.


by WIZnet


yes, you are right: 1228 is fine and 1244 has problems (not all parts, but approx. 60%). I bought these parts from my standard distributor here in germany, like the others, too…

A question from my side: Do you know any “external” circumstance which I can look for, which can lead to these problems: Link stable, correct register setup, but no response to ARP, PING and connection attempts?? (I checked the parts, the board (via’s and solder pads and joints), the clock, the supply (3.3V and 1.8V internal) etc.)…




Please make RMA and ship back those all failed samples.
Also we will inform this issue to our branch office in Germany.
When we get them, we will retest and find out what the problem is.
After that we will share with you when we figure out the problems.

I feel bad making you inconvenient.


JC Kim.

Just for your reference, 1244 lot was porduced 130K pcs and now out of stock in HQ.
This is the first time.