DS1821

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DS1821 BLOCK DIAGRAM Figure 1

OPERATION

Temperature Measurement

The DS1821 measures temperatures through the use of an onboard proprietary temperature measurement

technique. The temperature reading is provided in an 8-bit, two’s complement reading. Table 1 describes

the exact relationship of output data to measured temperature. The data is transmitted serially over the 1-

Wire interface. The DS1821 can measure temperature over the range of -55

°C to +125°C in 1°C

increments. For Fahrenheit usage, a lookup table or conversion factor must be used. Please refer to

Application Note 105 for the method to increase the resolution of the DS1821.

TEMPERATURE/DATA RELATIONSHIPS Table 1

TEMPERATURE

DIGITAL

OUTPUT

(Binary)

DIGITAL

OUTPUT

(Hex)

+125°C

01111101

7Dh

+25°C

00011001

19h

0°C

00000000

00h

-1°C

11111111

FFh

-25°C

11100111

E7h

-55°C

11001001

C9h