DS3231
Epson alternative: RX8901CE
You want to replace the DS3231 — as a second source, because of board area, or because a new design has to run on a coin cell for years. Here the type is set against the closest Epson type feature by feature, with the points that speak for and against the change. The same comparison applies to the DS3231S, DS3231SN and DS3231N.
Features of the DS3231: two time-of-day alarms, programmable square-wave output, 32 kHz output and a digital temperature sensor readable over I²C.
DS3231 versus RX8901CE
| DS3231 — Analog Devices | RX8901CE — Epson | |
|---|---|---|
| Manufacturer | Analog Devices (formerly Maxim, originally Dallas) | Epson (Seiko Epson) |
| Status | Active series type | Active series type |
| Interface | I²C (400 kHz) | I²C (400 kHz) |
| Crystal integrated | yes — TCXO with the crystal in the package | yes — DTCXO, factory calibrated |
| Accuracy | ±2 ppm from 0 to +40 °C · ±3.5 ppm from −40 to +85 °C | ±3.0 ppm across −40 to +85 °C (DTCXO) |
| Timekeeping current | 0.84 µA typ. at 3.63 V · 3.0 µA max. | 240 nA typ. · 1.5 µA max. |
| Supply | 2.3 – 5.5 V (VCC and VBAT) | 1.6 – 5.5 V · clock down to 1.1 V |
| Max. temperature | +85 °C (DS3231SN) · +70 °C (DS3231S) | −40 … +105 °C |
| Package | SO-16, 300 mil wide | CE 3.2 × 2.5 × 1.0 mm · 8.0 mm² footprint |
| Extras | temperature sensor over I²C, two alarms, 32 kHz output | 32 timestamps (FIFO or 3 channels), 256 byte SRAM, self-monitoring |
What speaks for and against the change
We sell Epson — and we still say where the competitor is better. You would notice it at the first datasheet comparison anyway.
Honestly
- In the narrow band from 0 to +40 °C the DS3231 is specified at ±2 ppm — tighter than anything Epson quotes there
- It carries a digital temperature sensor that the host can read over I²C. Epson does not offer that
- Extremely widespread, with ready-made drivers for every platform and plenty of reference designs
The difference
- Current: 240 nA typical against 840 nA, and 1.5 µA against 3.0 µA in the worst case. On a coin cell that decides whether the clock survives storage
- Board area: 8.0 mm² against a 300-mil SO-16 — roughly a factor of ten
- Temperature: +105 °C against +85 °C, and the DS3231S variant stops at +70 °C
- Across the full industrial range the RX8901CE is the tighter part: ±3.0 ppm against ±3.5 ppm from −40 to +85 °C
- 32 timestamps in a FIFO or on three channels, 256 byte SRAM and self-monitoring — the DS3231 has none of that
Frequently asked questions
What is the Epson alternative to the DS3231?
The closest match is the RX8901CE, with the RX8900CE as a second option. It is not a drop-in replacement: package, pinout and register map differ, so layout and firmware have to be adapted. What you get in return is a tenth of the board area and roughly a quarter of the timekeeping current.
Is the DS3231 really accurate to ±2 ppm?
Yes, but only from 0 to +40 °C. Across the full industrial range of −40 to +85 °C the datasheet specifies ±3.5 ppm. Epson's RX8901CE is specified at ±3.0 ppm across −40 to +85 °C, so over the whole range it is the tighter part.
How much current does the DS3231 draw compared with an Epson RTC?
The DS3231 datasheet gives 0.84 µA typical at 3.63 V and up to 3.0 µA maximum for timekeeping. The RX8901CE runs at 240 nA typical and 1.5 µA maximum. Over a long backup period on a coin cell that is the difference between months and years.
Who supplies an alternative to the DS3231 in Europe?
Timing Devices Europe in Ladenburg near Heidelberg, Germany stocks the complete Epson RTC programme in its own warehouse — physically on site, not at the manufacturer. Samples, comparison and series demand in one go, answered the same working day.
Samples and a comparison for the DS3231.
Tell us which version you use today, together with quantity and date. We will put together the Epson equivalent with its datasheet and the migration effort — from our own warehouse in Ladenburg near Heidelberg, Germany.