lm94021-mda National Semiconductor Corporation, lm94021-mda Datasheet - Page 11

• Manufacturer Part Number: lm94021-mda
• Description: Multi-gain Analog Temperature Sensor
• Manufacturer: National Semiconductor Corporation

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
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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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