DS1620

DS1620 FUNCTIONAL BLOCK DIAGRAM Figure 1

The DS1620 measures temperature using a bandgap-based temperature sensor. The temperature reading

is provided in a 9–bit, two’s complement reading by issuing a READ TEMPERATURE command. The

data is transmitted serially through the 3–wire serial interface, LSB first. The DS1620 can measure

temperature over the range of -55°C to +125°C in 0.5°C increments. For Fahrenheit usage, a lookup table

or conversion factor must be used.

Since data is transmitted over the 3–wire bus LSB first, temperature data can be written to/read from the

words, with the most significant 7 bits being ignored or set to 0, as illustrated in Table 3. After the MSB,

the DS1620 will output 0s.

Note that temperature is represented in the DS1620 in terms of a ½°C LSB, yielding the 9–bit format

shown in Figure 2.

TEMPERATURE, TH, and TL REGISTER FORMAT Figure 2

X

X

X

X

X

X

X

1

1

1

0

0

1

1

1

0

LSB

T = -25°C

MSB

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