I need to use an instrumentation amp for thermocouple measurements.
Seems to me that good laser trimmed IA's are increasingly hard to find and expensive. By contrast very low offset op amps and 0,1% resistors are increasingly available and cheap.
What's the best way to go? Anybody know good cheap IA's or are discrete designs the way to go?
Hard too find? I don't think so. TI and Analog produce rather many of them.
Lasertrimming is expensive.
But 0.1% resistor give you only about 60 db CMRR, which even the cheapest integrated IA outperforms easily. Not to speak about temperature drift, offset drift etc. etc.
IMHO discrete IA designs can in no way compete with integrated solutions, it will take you a very long development time and will cost much more than even the more expensive ones. So why bother with a discrete design??
Klaus
Hello Klaus,
this is wrong. It depends on the gain of your INA with a gain of 1000 you get ca 110 dB using 0.1% resistors.
I aggree with you.
Marte
Hi Roger,
Where do you buy your devices? I can't follow this claim.
Try
Marte
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