DA6505.005

11 June 2018

37 (44)

SENSOR BRIDGE RESISTANCE TEMPERATURE SENSING

The MAS6505 supports temperature sensing using temperature dependency of sensor bridge resistance. This is

four internal resistors R1, R2, R3 and R4. See Figure 13.

Figure 13. Temperature measurement circuit configuration in sensor bridge resistance temperature sensing

The formed Wheatstone bridge is usually balanced (output signal close to zero) at room reference temperature

See table 7 for register details. The temperature signal has following characteristics and it is the input signal for

the MAS6505 AFE in the temperature measurement.

( )

(

)





(

)





























+

+

−



+



−



+



−

+



=

1

1

1

1

1

1

4

3

4

2

1

R

R

T

T

TC

R

T

T

TC

R

R

R

VDDS

T

V

REF

R

REF

S

S

IN

Equation 15

VDDS = sensor supply voltage; 1.68V typ

]

]

C]

C]

C) [C]

T = actual sensor temperature to be measured [

C]

From equation 9 we see that the temperature signal has a rising temperature dependency vs. temperature when

Figure 14.

Figure 14. Temperature signals of positive and negative TC bridge resistance sensors

GND

R2

R4

R1

R3

PI

NI

VDD

R

S

V

IN