DESCRIPTION
The DS1822-PAR digital thermometer provides 9 to 12–bit centigrade temperature measurements and has an alarm function with nonvolatile user-programmable upper and lower trigger points. The DS1822-PAR does not need an external power supply because it derives power directly from the data line (“parasite power”). The DS1822-PAR communicates over a 1-wire bus, which 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 +100°C and is accurate to ±2.0°C over a range of –10°C to +85°C.

FEATURES
• Unique 1-wire interface requires only one port pin for communication
• Derives power from data line (“parasite power”)—does not need a local power supply
• Multi-drop capability simplifies distributed temperature sensing applications
• Requires no external components
• ±2.0°C accuracy from –10°C to +85°C
• Measures temperatures from –55°C to +100°C (–67°F to +212°F)
• Thermometer resolution is user-selectable from 9 to 12 bits
• Converts temperature to 12-bit digital word in 750 ms (max.)
• User–definable temperature alarm settings
• Alarm search command identifies and addresses devices whose temperature is outside of programmed limits (temperature alarm condition)
• Software compatible with the DS18B20-PAR
• Ideal for use in remote sensing applications (e.g., temperature probes) that do not have a local power source