AN4071

Window comparator

Doc ID 022939 Rev 1

25/27

The TS332 is a dual micropower and low-voltage comparator. It can operate with a supply

voltage ranging from 1.6 to 5.5 V with only 20

μA current consumption per operator. In

addition, rail-to-rail inputs and a temperature range of -40 °C to +125 °C makes it ideal for

a wide range of applications.

With good accuracy about 25 °C, the STLM20 transfer function can be described by the

parabolic transfer function expressed in Equation 12:

Equation 12

Based on the STLM20 transfer function equation, for the considered temperature range

25

and equals 1.691 V.

a compromise between noise sensitivity and low impact on the supply current of the

application. The resistors in the divider are:

A recalculation of the temperature range can be made with these resistors.

Equation 13

The temperature can be expressed from the voltage of the STLM20:

Equation 14

For better range setting precision, fixed resistors in the voltage divider bridge can be

replaced by variable resistors. Note that, temperature setting depends on the supply

voltage. Thanks to the micro power TS332 comparator, the power current consumption of

the application is typically only 50

μA at 25 °C and max. 74 μA over full temperature range.

T

1481.96

–

2.1962

10

6

1.8639

V

OUT

–

3.88

10

6

–

•

---------------------------------------

+

•° CV

,

()

+

=