6.0 Selectable Gain for

Optimization and In Situ Testing

The Gain Select digital inputs can be tied to the rails or can

be driven from digital outputs such as microcontroller GPIO

pins. In low-supply voltage applications, the ability to reduce

the gain to -5.5 mV/˚C allows the LM94021 to operate over

the full -50 ˚C to 150 ˚C range. When a larger supply voltage

is present, the gain can be increased as high as -13.6

mV/˚C. The larger gain is optimal for reducing the effects of

noise (for example, noise coupling on the output line or

quantization noise induced by an analog-to-digital converter

which may be sampling the LM94021 output).

Another application advantage of the digitally selectable gain

is the ability to perform dynamic testing of the LM94021

while it is running in a system. By toggling the logic levels of

the gain select pins and monitoring the resultant change in

the output voltage level, the host system can verify the

functionality of the LM94021.

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