Before I buy some parts I want to check something with you guys
if I had a two gain stages in a row. each gain stage has a gain of 10.000004 (assuming 1k/10k with 0.2ppm drift, drift in opposite directions over 1C)
so the total error is 10.000004*10.000004=100.00008
error is 0.0000799% / degree celcius
if i instead had a single stage, with 0.2 ppm resistors, of 1000 and 100000 ohm
1000*(0.2/10^6) = 0.0002 = 999.9998 ohm
100000*(0.2/10^6) = 0.02 = 100000.02 ohm
gain = 100.00004, gain error = 0.000039%
so, if i split my gain over 2 stages rather then 1 stage my temperature coefficient error doubles?
these prices got me so anxious i need my hand held lol
* I don't care about offset error, only gain error