DESCRIPTION
The DS1822 digital thermometer provides 9- to 12-bit centigrade temperature measurements and has an alarm function with NV user-programmable upper and lower trigger points. The DS1822 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of –55°C to +125°C and is accurate to ±2.0°C over the range of –10°C to +85°C. In addition, the DS1822 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply.

FEATURES
■ Unique 1-Wire® interface requires only one
   port pin for communication.
■ Each device has a unique 64-bit serial code
   stored in an on-board ROM.
■ Multidrop capability simplifies distributed
   temperature-sensing applications.
■ Requires no external components.
■ Can be powered from data line. Power supply
   range is 3.0V to 5.5V.
■ Measures temperatures from -55°C to +125°C
   (-67°F to +257°F).
■ ±2.0°C accuracy from -10°C to +85°C.
■ Thermometer resolution is user-selectable
   from 9 to 12 bits.
■ Converts temperature to 12-bit digital word in
   750ms (max.)
■ User-definable nonvolatile (NV) alarm
   settings.
■ Alarm search command identifies and
   addresses devices whose temperature is
   outside of programmed limits (temperature
   alarm condition).
■ Software compatible with the DS18B20.
■ Applications include thermostatic controls,
   industrial systems, consumer products,
   thermometers, or any thermally sensitive
   system.