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Best practice for amplifing and digitizing pressure sensor output (1MHz-20MHz)

Question asked by Albertin on Apr 3, 2017
Latest reply on Apr 3, 2017 by Dongfeng



I am currently working on pressure sensor design and fabrication. Until now, for testing, I was amplifying the signal from my pressure sensor (fabricated in the lab) using a AD8015 and monitoring the output of the AD8015 using an oscilloscope. The sensor can be represented as a 5pF capacitor.


The setup works fine. However, now I want to fabricate a "stand-alone" system that can do the following :

1- Amplify the signal from the sensor

2- Digitize the signal wiht an ADC

3- Send the signal to an FPGA.


In order to reduce time of conception I was planning to stick to the AD8015 as it works fine for me. However, the output signal from the AD8015 is in the rang of 0.1mV to 5mV. Hence, I would like to add an additional amplifier stage. 


From the huge amount of diff amps I am not sure which one to chose. I was thinking of using  OPA211 1.1nV/rtHz Noise, Low-Power, Precision Operational Amplifier | . Maybe, there is one from AD that is more suitable? Is there a AD amp that is normally used to amplify the AD8015? I am looking for a maximum gain and I want to attack in the future an ADC. The signal has a frequency of around 1-2MHz and I will probably scale it in the future to 15-20MHz.