Posting on behalf of customer.
The F2838xD TRM ("Designing an External Reference Circuit") recommends two part numbers for op-amp buffers, OPA320 & OP350. Customer is looking for a suitable op-amp (automotive qualified, 4-channel) to implement an external reference. What are the requirements for the opamp? Can you advise on an automotive qualified, 4-channel alternative?
Hi Gus,
To evaluate an arbitrary VREFHI driver, see the methodology developed in the TI precision labs training series "Driving the reference input on a SAR ADC": 
Specifically for an automotive rated driver for this device, note that we do allow 1 driver for every 2 VREFHI (see the TRM diagram "ADC Shared Reference System") so OPA2320-Q1 is the obvious choice.
If the customer wants the absolute best possible performance and wants to drive every VREFHI independently, OPA2320-Q1 x 2 would probably be the best choice. This could also be useful if ADCs are being used redundantly to check each other for safety monitoring: the pairs of ADCs monitoring each other can use different op-amp instances, eliminating a single-point of failure. Otherwise, if a x4 op-amp is required, then OPA4197-Q1 or TLV4197-Q1 appear to be possible options, but they will need to be evaluated to determine if 10MHz is sufficient bandwidth. They will also need to be evaluated to determine stability when driving the large capacitive load on the VREFHI pin.
