How to correct PGA gain errors? | Cypress Semiconductor
How to correct PGA gain errors?
I've been creating a circuit that uses a PGA as a differential amplifier with it's reference (V-) input connected to a non-zero reference voltage (call it Vref).
I then convert the PGA output via a DelSig ADC, and the readings are then converted to a temperature.
I noticed that the reading errors (percentage deviation from an expected value) increases as I increase the PGA gain. So at the moment, I'm convinced that the PGA gain is the cause of this.
How then could I correct this error?
I'd love to provide the schematics but I'm afraid I can't.
Some info :
> PGA at Minimum Power, V+ is not changing rapidly (consider it constant)
> ADC is in buffer bypass mode, single sample @ 60 sps, 20 bits, using internal 1.024 reference, differential mode
> Reference voltage is provided by a VDAC buffered with an opamp follower which is in low power mode