RX8901CE
Real-time clock module by Epson
The RX8901CE is a real-time clock module from Epson with a built-in 32.768 kHz crystal — no separate watch crystal on the board, no load capacitance and layout risk. Interface I²C, package CE · 3.2 × 2.5 × 1.0 mm, standby current 240 nA typ. · 1500 nA max., accuracy ±3.0 ppm over −40 … +85 °C (DTCXO), operating range −40 … +105 °C. The most accurate type in the programme. 32 time stamps (FIFO or 3 channels), 256 bytes of SRAM, self-monitoring.
What the RX8901CE can do
Digitally temperature compensated — the stated accuracy holds across the whole temperature range, not only at +25 °C.
Detects the loss of the main supply and switches to the backup source on its own — compared with a diode-OR arrangement the MOS switch saves leakage current and voltage drop.
Events are recorded with their time inside the device, without the MCU having to wake up for it.
Reports an oscillation stop instead of quietly delivering the wrong time.
Order codes and datasheets
Every order code has its own printable datasheet with all recorded figures.
| TDE item | Epson designation |
|---|---|
| 91-0555 | RX8901CE XS |
| 91-0556 | RX8901CE XS |
| 91-0557 | RX8901CE XS |
| 91-0558 | RX8901CE XS |
| 91-0583 | RX8901CE XS |
| 91-0584 | RX8901CE XS |
| 91-0585 | RX8901CE XS |
| 91-0586 | RX8901CE XB |
| 91-0587 | RX8901CE XB |
| 91-0589 | RX8901CE XS |
| 91-0590 | RX8901CE XB |
| 91-0591 | RX8901CE XB |
| 91-0592 | RX8901CE XB |
| 91-0593 | RX8901CE XS |
There are 19 order codes for this family in the programme — you will find the rest through the datasheet search.
Alternatives in the Epson programme
If the RX8901CE is not quite the right fit — these types come closest:
RX4901CE
Same series, SPI instead of I²C. Otherwise largely identical figures.
RA8000CE
AEC-Q100 version, delivered after separate release by Epson. Operation up to −40 … +125 °C.
All 40 families with filters for interface, package, standby current and temperature: real-time clock finder.
Frequently asked questions about the RX8901CE
How accurate is the RX8901CE?
±3.0 ppm over −40 … +85 °C (DTCXO). Because the device is digitally temperature compensated, that figure holds across the whole temperature range.
How much current does the RX8901CE draw in backup?
240 nA typ. · 1500 nA max.. With a 225 mAh coin cell that is enough for many years of pure timekeeping on paper; the self-discharge of the cell usually becomes the limiting factor.
Which interface does the RX8901CE use?
I²C. Package: CE · 3.2 × 2.5 × 1.0 mm.
Where can I buy the RX8901CE in Europe?
Timing Devices Europe stocks the Epson RTC programme in its own warehouse in Ladenburg near Heidelberg, Germany — physically on site, not at the manufacturer. Samples, series demand and second-source assessment in one go, answered the same working day.
Enquire about the RX8901CE.
We stock the Epson RTC programme in our own warehouse in Ladenburg near Heidelberg, Germany. Tell us tolerance grade, packing, quantity and date — answered the same working day.