OUT

V

11.77 mV / C

T

1.8576 V

q u

OUT

MAX

OUT

MAX

E

9

7

9

7

± P

7

7

u

6

P

7 ±

u

u

OUT

V

11.69 mV / C

T

1.8863 V

q u

6

2

2

OUT

V

3.88

10

T

1.15

10

T

1.8639 V

u

u

u

u

9

TMP20

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SBOS466B – DECEMBER 2009 – REVISED DECEMBER 2018

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Copyright © 2009–2018, Texas Instruments Incorporated

7.3 Feature Description

7.3.1 Transfer Function

The analog output of the TMP20 over the –55°C to +130°C temperature range corresponds to the parabolic

transfer function shown in

Added Receiving Notification of Documentation Updates section:

Where:

•

the temperature (T) is in °C.

(1)

When solving for temperature, the equation is shown as Equation 2:

(2)

These equations apply over the entire operating range of –55°C to +130°C.

A simplified linear transfer function referenced at 25°C is shown in Equation 3:

(3)

Linear transfer functions are calculated for limited temperature ranges by calculating the slope and offset for that

limited range, where slope is calculated by Equation 4:

Where:

•

T equals the temperature at the middle of the temperature range of interest

(4)

The offset in the linear transfer function is calculated with Equation 5:

where

•

VOUT(TMAX) is the calculated output voltage at TMAX as determined from

Added Receiving Notification of Documentation Updates section.

(5)

VOUT(T) is the calculated output voltage at T as calculated by

Added Receiving Notification of Documentation Updates section.

7.3.1.1 Example 1

Determine the linear transfer function for –40°C to +110°C.

TMIN = –40°C; TMAX = 110°C; therefore, T = 35°C

m = –11.77mV/°C

VOUT (110°C) = 0.5520 V

VOUT (35°C) = 1.4566 V

b = 1.8576 V

The linear transfer function for –40°C to +110°C is shown in Equation 6:

(6)