I need to redesign a hardware composed with a variable (0/+80db) amplifier stage with a LOGDAC AD7111 followed by a 16 bits ADC AD7722.
The signal frequency is around 5Khz. I don't find any modern replacement for the AD7111. Is there another solution to replace this design ?
The goal of this design is to measure the reflected IR signal by a photodiode from very dark material and from very reflectif white material.
With a optical reference chanel, the processor adjust the first amplifier stage from +0 to +80dB with the AD7111 and then measure the signal with the 16 bits range precision of the second stage.