The DS1620 Digital Thermometer and Thermostat provides 9–bit temperature readings which indicate the temperature of the device and has three thermal alarm outputs, can also act as a thermostat.
The DS1620 provides temperature measurements from –55 °C to +125 °C in 0.5 °C steps using a band‑gap sensor and outputs the result as a 9‑bit two's‑complement word. It features three thermostat outputs (THigh, TLow, Tcom) that can be programmed via non‑volatile registers.
Communication is performed over a simple 3‑wire serial bus (RST, CLK, DQ). The device can operate in stand‑alone mode with the CLK/CONV pin initiating conversions, or be controlled by a CPU. Detailed electrical specifications, command set, and timing diagrams are included for hardware designers.
| Supply voltage range | 2.7 V to 5.5 V |
|---|---|
| Temperature measurement range | -55 °C to +125 °C |
| Temperature resolution | 0.5 °C (9‑bit) |
| Thermostat outputs | THigh, TLow, Tcom (high/low combination) |
| Conversion time | 750 ms (max) |
| Logic 0 output voltage | 0.4 V |
| Logic 1 output voltage | 2.4 V |
| Active supply current | 1 mA (typical) |
| EEPROM write cycle time | 4 ms to 10 ms |
| EEPROM endurance | ≥50 k writes |
| EEPROM data retention | 10 years |
The DS1620 operates with a supply voltage between 2.7 V and 5.5 V.
Temperature is read as a 9‑bit two's‑complement word over the 3‑wire serial interface.
The THigh, TLow, and Tcom pins provide high‑temperature, low‑temperature, and combined alarm signals.
A conversion takes up to 750 ms.