RX-4045SA
Real-time clock module by Epson
The RX-4045SA 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 SPI, package SA · SOP-14, standby current 480 nA typ., accuracy ±5.0 ppm @ +25 °C, operating range −40 … +85 °C. SPI counterpart to the RX-8025SA.
What the RX-4045SA can do
The tolerance figure applies at +25 °C. Over temperature the built-in crystal follows the usual parabola.
Order codes and datasheets
Every order code has its own printable datasheet with all recorded figures.
| TDE item | Epson designation |
|---|---|
| 91-0001 | RX-4045SA AA |
| 91-0036 | RX-4045SA AC |
| 91-0080 | RX-4045SA AA/AC |
| 91-0081 | RX-4045SA AA/AC |
| 91-0082 | RX-4045SA AA/AC |
| 91-0083 | RX-4045SA AA/AC |
| 91-0221 | RX-4045SA AA/AC |
| 91-0222 | RX-4045SA AA/AC |
| 91-0223 | RX-4045SA AA/AC |
| 91-0224 | RX-4045SA AA/AC |
| 91-0237 | RX-4045SA AA/AC |
Alternatives in the Epson programme
If the RX-4045SA is not quite the right fit — these types come closest:
RX-8025SA
Same series, I²C instead of SPI. Otherwise largely identical figures.
RX-4045NB
The same series in the NB · SON-22 package. on request · −40 … +85 °C
RX4901CE
If the clock has to hold over temperature as well: DTCXO, ±3.0 ppm over −40 … +85 °C (DTCXO).
All 40 families with filters for interface, package, standby current and temperature: real-time clock finder.
Frequently asked questions about the RX-4045SA
How accurate is the RX-4045SA?
±5.0 ppm @ +25 °C. This figure applies at +25 degrees Celsius. Over temperature the built-in crystal follows the usual parabola — if the clock has to hold when hot and cold as well, a DTCXO type is the right choice.
How much current does the RX-4045SA draw in backup?
480 nA typ.. 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 RX-4045SA use?
SPI. Package: SA · SOP-14.
Where can I buy the RX-4045SA 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 RX-4045SA.
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.