DS3234 is a low-cost, extremely accurate SPI™ bus real-time clock (RTC) with an integrated temperature- compensated crystal oscillator (TCXO) and crystal. The DS3234 incorporates a precision, temperature-compen- sated voltage reference and comparator circuit to moni- tor VCC. When VCC drops below the power-fail voltage (VPF), the device asserts the RST output and also dis- ables read and write access to the part when VCC drops below both VPF and VBAT. The RST pin is monitored as a pushbutton input for generating a reset externally. The device switches to the backup supply input and main- tains accurate timekeeping when main power to the device is interrupted. The integration of the crystal res- onator enhances the long-term accuracy of the device as well as reduces the piece-part count in a manufactur- ing line. The DS3234 is available in commercial and industrial temperature ranges, and is offered in an industry-standard 300-mil, 20-pin SO package. The DS3234 also integrates 256 bytes of battery-backed SRAM. In the event of main power loss, the contents of the memory are maintained by the power source con- nected to the VBAT pin. The RTC maintains seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjust- ed for months with fewer than 31 days, including correc- tions for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. Two programmable time-of-day inputs allow setting alarms and timers.
The DS3234 is a low‑cost, highly accurate SPI‑bus real‑time clock with an integrated temperature‑compensated crystal oscillator and 256‑byte battery‑backed SRAM. It offers time‑keeping, leap‑year correction, 12/24‑hour format, two programmable alarms and a square‑wave output.
The datasheet details electrical characteristics, pin functions, timing diagrams, operating temperature ranges (commercial 0 °C to +70 °C, industrial –40 °C to +85 °C), supply requirements, and package information for the 20‑pin SO version.
| Accuracy | +2 ppm (0 °C‑40 °C), +3.5 ppm (‑40 °C‑85 °C) |
|---|---|
| Operating Temperature Range (Commercial) | 0 °C to +70 °C |
| Operating Temperature Range (Industrial) | -40 °C to +85 °C |
| Package | 300‑mil, 20‑pin SO |
The device provides ±2 ppm accuracy from 0 °C to +40 °C and ±3.5 ppm from –40 °C to +85 °C.
It uses a battery‑backup input (VBaT pin) that powers an internal 256‑byte SRAM and keeps the clock running.
The DS3234 provides two programmable time‑of‑day alarms.