Owner manual

Functional Description (Continued)

7.0 TEMPERATURE MEASUREMENT SYSTEM

The LM80 bandgap type temperature sensor and ADC per-

form 9-bit or a 12-bit two’s-complement conversions of the

temperature. An 8-bit digital comparator is also incorporated

that compares the readings to the user-programmable Hot

and Overtemperature setpoints, and Hysteresis values.

7.1 Temperature Data Format

Temperature data can be read from the Temperature, T

hot

hot hyst

and T

os hyst

setpoint registers; and written to the

hot

hot hyst

and T

os hyst

setpoint registers. T

hot

set

point, T

hot hyst

set point, T

set point and T

os hyst

tempera-

ture data is represented by an 8-bit, two’s complement word

with an LSB (Least Significant Bit) equal to 1˚C:

Temperature Digital Output

Binary Hex

+125˚C 0111 1101 7Dh

+25˚C 0001 1001 19h

+1.0˚C 0000 0001 01h

+0˚C 0000 0000 00h

−1.0˚C 1111 1111 FFh

−25˚C 1110 0111 E7h

−55˚C 1100 1001 C9h

DS100040-20

(Non-Linear Scale for Clarity)

FIGURE 8. 9-bit Temperature-to-Digital Transfer

Function

DS100040-16

(Non-Linear Scale for Clarity)

FIGURE 9. 12-bit Temperature-to-Digital Transfer

Function

LM80