I was wondering if the ADA4891-1 can be used as a unity gain buffer? I have a unity gain stable amp on my PCA already but for consolidation of parts and for operating temperature range, I would like use an existing amp I have on my board, the ADA4891-1. My input signal is a relatively stable output from a DAC which varies between 0 and +3.3V. You can treat the DAC signal as DC. My other option is to use a new part such as the ADA4622-1 which is unity gain stable and works over -40C to 125C
Your advice would be much appreciated.
Yes, ADA4891-1 is unity-gain stable. Just do note that it's not "true" Rail-to-Rail since there will be some headroom from the supply rails. You must consider that the amplifier has 10 mV footroom and 20 mV headroom on the output. ADA4622-1 could be a good option for you too. Just check on the Input Voltage Range and Output Voltage Range of the amplifiers to make sure that the entire DAC voltage range is optimized. Both amplifiers could work on −40°C to +125°C temp. range.