1-Wire Digital Thermometer DS1820

FEATURES                                                                                      PIN ASSIGNMENT

• 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 set-

  tings

• Alarm search command identifies and addresses

  devices whose temperature is outside of pro-

  grammed limits (temperature alarm condition)

• Applications include thermostatic controls, industrial

  systems, consumer products, thermometers, or any

  thermally sensitive system

PIN DESCRIPTION

GND             – Ground

DQ               – Data In/Out

VDD             – Optional V_DD

NC               – No Connect

DESCRIPTION

The DS1820 Digital Thermometer provides 9–bit tem-

perature 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 sen-

sors 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.

DS1820 BLOCK DIAGRAM Figure 1