DESCRIPTION
The DS1820 Digital Thermometer provides 9–bit temperature readings which indicate the temperature of the device.
Information is sent to/from the DS1820 over a 1–Wire interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS1820. Power for reading, writing, and performing temperature conversions can be derived from the data line itself with no need for an external power source.
Because each DS1820 contains a unique silicon serial number, multiple DS1820s can exist on the same 1–Wire bus. This allows for placing temperature sensors in many different places. Applications where this feature is useful include HVAC environmental controls, sensing temperatures inside buildings, equipment or machinery, and in process monitoring and control.

FEATURES
• Unique 1–WireTM interface requires only one port pin for communication
• Multidrop capability simplifies distributed temperature sensing applications
• Requires no external components
• Can be powered from data line
• Zero standby power required
• Measures temperatures from –55°C to +125°C in 0.5°C increments. Fahrenheit equivalent is –67°F to +257°F in 0.9°F increments
• Temperature is read as a 9–bit digital value.
• Converts temperature to digital word in 200 ms (typ.)
• User–definable, nonvolatile temperature alarm settings
• Alarm search command identifies and addresses devices whose temperature is outside of programmed limits (temperature alarm condition)
• Applications include thermostatic controls, industrial systems, consumer products, thermometers, or any thermally sensitive system