Just a heads up for users of DS1302ZN.

I've just spent the entire day replacing these chips that were a recent purchase from Allied, and will probably be spending the next couple days doing the same thing. Every single one that were mounted on boards that I've been using for several years is failing. Unfortunately some even made it to customers, as some seem to work long enough to pass testing. After that they become intermittent. The crystal still oscillates, but it doesn't count time anymore.

After replacing them with chips that have different date codes, everything is fine again.

On the back it shows the chips were made in the Philippines, whereas the ones I'm replacing them with show Malay.

Date code is 9945A3. Beware, and return them before mounting if you get them.

HTH,
DT