The DS1672 is a 32-bit binary counter / calendar chip from Maxim, using the I2C bus, an internal low-voltage oscillator, automatic power-fail detection and switching circuitry, power-fail reset output, trickle-charge capability and a wide operating temperature range of -40°C to +85°C.
The DS1672 incorporates a 32‑bit counter and power‑monitoring functions. It counts seconds and can be used to derive time‑of‑day, week, month, and year via a software algorithm. The device features an I²C serial interface, automatic power‑fail detection, a power‑fail reset output, low‑voltage oscillator operation (1.3 V min), and trickle‑charge capability, and is UL‑recognized for operation from –40 °C to +85 °C.
Pin descriptions, electrical characteristics, and package information are provided for PDIP, SO, and µSOP variants. The datasheet includes absolute maximum ratings, recommended operating conditions, DC and AC electrical characteristics, a detailed address map, trickle‑charger control, thermal data, and revision history.
| Counter width | 32‑bit |
|---|---|
| Interface | I²C serial interface |
| Operating temperature range | -40 °C to +85 °C |
| Low‑voltage oscillator operation | minimum 1.3 V |
| Trickle‑charge capability | Enabled via TCS bits |
The 7‑bit I²C slave address is 0x68 (binary 1101000).
A 32.768 kHz crystal with series resistance ≤45 kΩ and load capacitance of 6 pF is recommended.