Other Parts Discussed in Thread: LM7705
Hello together,
I would like to measure the Input Offset Voltage of the OPA189:
The OPA189 has a typical Input Offset Voltage of ±0.4 μV and max. ±3 μV.
I have a HP3458A Multimeter, which can measure DC Voltage in Microvolt range. So I bought the Evaluation Modul DIYAMP-SOIC-EVM and I solder two resistance with 10 kOhm that the gain of the OPA is two.
In the case that the OPA is near at the specific Offset Voltage I should measure a DC Voltage at the Output of about ±6 μV max.
But therefore I measure a Output Voltage of about 140 μV.
That is the circuit:
With:
OPA189
R1 = R2 = 10 kOhm
C1 = 0,1 μF
I hope you can help me to improve my circuit,
Marv