Beware of DS1302ZN with date code 9945A3

[Darrel Taylor]

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

[amindzo]

Hi,
could you explain more about this chip?
is it a time and date chip?

[Darrel Taylor]

Well, another day of changing chips. Uggg!

Yup, it's a time clock. 8-pin SOIC.

[amindzo]

Hi,
i haven't worked with this chip.i have worked with DS1307.
that chip is a time and calender chip.
i have all in formation about DS1307.if you use this chip i can help you.

about your problem:
if your chip has a battery pin,it won't be flaot
you should connect the batteries to it or connect it to ground

[Kman]

I have beed having a problum with a 1302 chip not updating the time when the micro and the 1302 are powered on the same 5 volt source.
Now I Keep the ds1302 running off the Backup battery, and use a extra pin on the micro to powerup the 1302, read the time, Turn it off.
Well its keeping time Now!!

[sayzer]

We had a similar production issue with 16F628A.

We ordered 5Kpcs and all were bad with EEPROM.

We returned the lot after serious discussions took place; and stopped the business with the supplier.

I am sure these kind of chips come out from the factory at a dead price and there is always someone selling them as if they were normal.


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[Darrel Taylor]

I can certainly understand what you went through Sayzer. I'm sure glad we didn't have 5k of them.

With the chips dated from 1999, I'm hoping it was just a stock mix-up from when Dallas was bought by Maxim in early 2001. Probably got transfered as good parts, much like the OLD manufacturing equipment that was transfered at NEW cost. (I watch the Stock Market too much)

Well, only have 25 boards left to replace them on. But I'm definately waiting till Allied gets new parts before I buy anymore there.

.