DS1847

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TEMPERATURE CONVERSION

The direct-to-digital temperature sensor measures temperature through the use of an on-chip temperature

measurement technique with an operating range from -40°C to +95°C. Temperature conversions are

initiated upon power-up, and the most recent result is stored in address locations E2h and E3h, which are

updated every 10ms. Temperature conversion will not occur during an active read or write to memory.

The value of each resistor is determined by the temperature-addressed look-up table that assigns a unique

value to each resistor for every 2°C increment with a 1°C hysteresis at a temperature transition over the

operating temperature range. This can be seen in Figure 2.

TEMPERATURE CONVERSION HYSTERESIS Figure 2

EXAMPLE TEMPERATURE READINGS Table 2

TEMP

BINARY DATA

HEX DATA

+95ºC

0010 1111 1000 0000

2F80h

+25.0625ºC

0000 1100 1000 1000

0C88h

-10.125ºC

1111 1010 1111 0000

FAF0h

-40ºC

1110 1100 0000 0000

EC00h

2

4

6

8

10

12

TEMPERATURE (C)

M6

M5

M4

M3

M2

M1

Increasing temp

Decreasing temp