3.0 Application Hints

3.1 LIGHT SENSITIVITY

The LM74A in die form should not be exposed to ultraviolet

light. Exposing the LM74A to bright sunlight will not immedi-

atly cause a change in the output reading. Our experiments

show that directly exposing the circuit side (pad side) of the

die to high intensity (

a wavelength of 254nm, for greater than 20 minutes will

deprogram the EEPROM cells in the LM74A. Since the

EEPROM is used for storing calibration coefficients, the

LM74A will function but the temperature accuracy will no

longer be as specified. Light can penetrate through the side

of the die as well.

4.0 Typical Applications

20017720

FIGURE 8. Temperature monitor using Intel 196 processor

20017719

FIGURE 9. LM74A digital input control using micro-controller’s general purpose I/O.

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