I want to amplify a signal within 0-50mVp-p and with the frequency range between 10KHz to 15MHz (or 10MHz).
first I have used two unity buffer to measure the signal (is similar to instrument Amp)
But when I simulated the circuit, AD8129 doesn't have a linear gain in the band of 10KHz to 10MHz. you can see the gain=Vout/Vin is not linear in the below pic:
so I decided to compensate the RF and RG (I mean feedback resistors) of AD8129 with some capacitors to have a linear gain like this article:
Adjustable Cable Equalizer Combines Wideband Differential Receiver with Analog Switches | Analog Devices
can you help me to design to have a maximum gain linearity with AD8129? (it's very important to me bcoz I have a medical application)
it's my email: email@example.com
Could you share your schematic please? From there, we could start what't going on. Thanks.
The "gain nonlinearity" that you are seeing in your simulation is normal. It is within the bandwidth limitations of AD8129. At gain of 20, it's -3 dB bandwidth is specified at 60 MHz. You will see that in figure 30 of the datasheet, the bandwidth start to roll-off at ~6 MHz. Beyond this said frequency, the expected gain would not be "linear" since it starts to drop. At gain of 20 and a flatband of 10 MHz, AD8129 alone would not be sufficient for your application. However, we could find you a viable solution from our amplifiers portfolio that will be suitable for your application.
Could you provide more details on your applications please?