Maxim Integrated has a handy website of various products that have reached the end of life (EOL), and break out some products into categories such as “not recommended for new designs” (in that they’re planning to be discontinued in the near future) and “no longer available”.
It turns out that several DS3231 variants are on the list at the time of this post:
| Status | Part Number |
| NRND | DS3231MZ/V+ |
| NRND | DS3231MZ/V+T |
| NLA | DS3231N/DIP |
| NLA | DS3231S |
| NLA | DS3231S#-W |
| NLA | DS3231S#C14 |
| NLA | DS3231S/T&R |
| NLA | DS3231S/T&R#C15 |
| NLA | DS3231SN |
| NLA | DS3231SN-C16 |
| NLA | DS3231SN/T&R |
Uh-oh. Does this mean the DS3231 is no more, as Ed Mallon mentions in an addendum to his post?
Fortunately, no. The DS3231 (both crystal based and MEMS-based) is still widely available in several variants.
I contacted Maxim and inquired what was going on, and the response was that the non-RoHS versions (e.g. with lead solder) are being discontinued, while the RoHS-compliant versions (designed by a “#” mark, like “DS3231SN#”) are still being actively produced and are recommended for use in new designs.
The RoHS-compliant versions have identical timekeeping specifications as the non-RoHS verisons.
Hopefully this helps to clarify things.
Here’s a report on the DS3231 models coming from China, as of March 2021. I bought the following from a Chinese eBay seller:
* (20) small DS3231 modules (with the yellow supercapacitor in many photos),
* (10) large DS3231 modules (with AT24C32 EEPROM module,and CR3032 battery holder)
Out of the (20) small modules, I got:
* (14) DS3231SN
* (5) DS3231M
* (1) DS3231N (which I assume is a fake?)
Out of the (10) large modules, I got:
* (3) DS3231SN
* (7) DS3231M