O
ozzy
- Jan 1, 1970
- 0
Hello!
I would like to address a problem I'm mulling over at the moment. I
have a micro-controller based circuit with a front end consisting of an
Instrumentation amplifier. I thought of applying zero volts to the
inputs (via pins from PIC) as a way of finding the sum of offset
voltages - via A/D converter. My worry is that this could affect the
high CMRR (120dB) needed at the input - can this be quantified?
Another alternative is to use Comparators of the PIC, but I'm already
using one of them. This circuit is battery operated (9V split supply)
and would therefore have to perform (lowest point) at 3V - ruling out a
CMOS switch.
These are just a few thoughts whizzing around me at the moment. Any
help on which way to go would be helpful.
Regards,
Ozzy.
I would like to address a problem I'm mulling over at the moment. I
have a micro-controller based circuit with a front end consisting of an
Instrumentation amplifier. I thought of applying zero volts to the
inputs (via pins from PIC) as a way of finding the sum of offset
voltages - via A/D converter. My worry is that this could affect the
high CMRR (120dB) needed at the input - can this be quantified?
Another alternative is to use Comparators of the PIC, but I'm already
using one of them. This circuit is battery operated (9V split supply)
and would therefore have to perform (lowest point) at 3V - ruling out a
CMOS switch.
These are just a few thoughts whizzing around me at the moment. Any
help on which way to go would be helpful.
Regards,
Ozzy.