DS1775

3 of 13

102299

the O.S. output will become active only after the measured temperature exceeds the respective trippoint a

consecutive number of times; the number of consecutive conversions beyond the limit to generate an O.S.

is programmable. The power–up state of the DS1775 is in the comparator mode with a single fault

generating an active O.S.

Digital data is written to/read from the DS1775 via a 2–wire interface, and all communication is MSb

first.

DS1775 FUNCTIONAL BLOCK DIAGRAM Figure 1

OPERATION–Measuring Temperature

The core of DS1775 functionality is its direct–to–digital temperature sensor. The DS1775 measures

temperature through the use of an on–chip temperature measurement technique with an operating range

from –55

°C to +125°C. Temperature conversions are initiated upon power–up, and the most recent result

is stored in the thermometer register. Conversions are performed continuously unless the user intervenes

by altering the configuration register to put the DS1775 into a shutdown mode. Regardless of the mode

used, the digital temperature can be retrieved from the temperature register by setting the pointer to that

location (00h, power–up default). The DS1775 power–up default has the sensor automatically performing

9–bit conversions continuously. Details on how to change the settings after power–up are contained in the

“OPERATION–Programming” section.