Other Parts Discussed in Thread: OPA820-HT, THS4281, THS4521-HT, OPA2333-HT, OPA211-HT, INA333-HT
I’m trying to select a driver amps for my ADC (ADS1278-HT), both on the inputs and the reference.
My requirements are,
System accuracy (trying to achieve better than 16 bits), so low noise, low offset, low temp drift are important
Low speed (my signals are less than 4Hz being sampled at 400Hz with a ADC clock speed of 800KHz. Two 1278s arranged in daisy chain mode using frame sync)
Temperature (This is high temperature application 170 degrees)
Sensor types (0-3.3V differential and 0.5-4.5V single ended)
For the reference I was planning on using the circuit in app note “18-Bit, 1MSPS Data Acquisition Block (DAQ) Optimized for
Lowest Distortion and Noise” but to a 2.5V ref and THS4281 for OPA820-HT. Does this seem sensible or would other parts be better?
For the differential signal I was planning on using THS4521-HT between the sensor and the ADC. Does this seem sensible or would other parts be better?
For the single ended signals I was planning on using two single supply 5V op amps to do a single ended to differential conversion like in app note SBAA265. The parts I’m looking at are the OPA820-HT, OPA211-HT, OPA2333-HT and INA333-HT.
The INA333-HT isn’t recommended for low gains at temperature so is discounted.
The OPA820-HT has quite large offsets and drifts so is discounted
The OPA211-HT has general all round performance so is a contender
The OPA2333-HT has very low offsets and drifts, low noise. But I’m unsure of its closed loop output impedance (another question has been posted) and it speed (if that’s important for my application)
So I’d like to know which op amps (-HT parts only) TI would recommend for the above?
Kind Regards
Martin
