The document describes the features and characteristics of DS1621 Digital Thermometer and Thermostat, including temperature measurement range, temperature reading accuracy, power supply range, conversion time, etc.
The DS1621 is a digital thermometer and thermostat that measures temperatures from -55 °C to +125 °C in 0.5 °C steps and operates from a 2.7 V to 5.5 V supply. It provides 9‑bit temperature readings via a 2‑wire serial (I²C‑compatible) interface and includes non‑volatile user‑definable high (TH) and low (TL) temperature limits.
The document describes pin functions, ordering options, conversion timing, thermostat control logic, bus protocol, and electrical specifications such as clock rates (100 kHz standard, 400 kHz fast) and input capacitance. It also includes timing diagrams and notes for reliable operation.
| Temperature range | -55 °C to +125 °C |
|---|---|
| Temperature resolution | 0.5 °C (9‑bit) |
| Supply voltage | 2.7 V to 5.5 V |
| Conversion time | 750 ms |
| Input capacitance | 5 pF (min) |
It measures temperatures from –55 °C to +125 °C.
It uses a 2‑wire serial (I²C‑compatible) interface with SDA and SCL open‑drain lines.