The AD8428 circuit test was built. The RF signal source input a 300K sinusoidal signal from the reverse end, and the forward input terminal is grounded. The output noise is very large. The output is tested by the oscilloscope, and the waveform jitter is serious. Even if the input is all grounded, there is still a big Noise output, is it a circuit problem or the noise problem of the AD8428 itself? How to solve it?
Jitter is not a common specs for instrumentation amplifier. But I've seen a jitter test and they usually capture a lot of cycle of the input source as well as the output of the DUT and then get the difference or the variation to make sure that the jitter is caused by the DUT and not by the RF signal source itself.
With regards to noise, the AD8428 has typical specs as shown on figure 29. Do you have measurement of AD8428 noise when its input is grounded on the scope? What is the magnitude?
Also, what is the magnitude of your input signal? Did you also intentionally lower the gain of the AD8428 by placing the R150?