Part Number: TLK10232
We have a module Testcard which employed TLK10232 for manufacture line test purpose. In the recent build of this card, we found 15 out of 80 cards be failure (failure rate almost 20%).
On the failure cards, we measured that the power/clock/reset signals to TLK10232’s input pins be normal, but TLK10232 has no signals on the Serdes output pins and MDIO access to it be failed.
We had swapped the TLK10232 chips between a normal card and a failure card, the failure followed with the TLK10232 chip.
We have several other kinds of formal boards be using TLK10232, and have not observed this kind of failure till now.
We compared the design of Testcard and formal boards, found that the TLK10232 TRST_N and TCK pins be left unconnected on Testcard while be handled on formal boards. According to Datasheet, it has internal pull-down for TRST_N, but no internal pulls for TCK.
We are suspecting that the cause of the issue possible be the TCK pin (or along with TRST_N) not handled in our Testcard design. As it’s BGA chip hence it’s hard for us to rework to verify it, but it’s better for us to get some infos before we re-spin the Testcard. So can you help to check if there’s this kind of failure risk if we left TCK/TRST_N pins unconnected?
