Here are two more low noise Op Amps in this never ending story.
The ADA4523 is a new very low noise chopper from Analog Devices. The datasheet was released April 20, 2020. I had to get samples from the factory because the distributor did not have any stock yet.
https://www.eevblog.com/forum/metrology/new-chopper-opamp-from-ad-ada4523-1/msg3076193/#msg3076193The LT6018 is a very low noise bipolar Op Amp. It was introduced in 2017 time frame. It has a 33V power supply limit and high bias currents. It has been on my list of Op Amps to test.
Today I just have the voltage noise spectrum for you. I collected current noise data also and will present that when I get some time.
I used +-5V power for both Op Amps. The enclosure was not temperature controlled this time. However the lab had less than +-0.3 deg C variation and the heavy insulated enclosures provided several hours of thermal lag. Each amplifier was configured for a gain of 80dB using 10 ohm and 100k ohm metal film SMD resistors. The amplifier outputs were measured with an HP35665A Low Frequency Spectrum Analyzer.
The new ADA4523 chopper has 20% less flicker noise than the OPA189. The bias current of my sample was 50pa.
The LT6018 is an exceptional bipolar opamp for white and flicker noise. It has roughly 1/3 the flicker noise of the LT1028A. The bias current of my sample was 61na.
More results to follow.