Both FFTs are noise floor of ADC. First with op amp and second without it. I really confused about this. I've designed many software radio cards including ADC, DAC, FPGA and ... and this circuit is first of them that failed in analog section…
I'd like to simulate diffrential amp(ADA4938-2) by using ADIsimPE.
So I imported ADA4938-2's spice model and define the symbol,
ADIsimPE doesn't show the correct symbol.
How do I define the correct symbol?
By the way ... I've paid an attention to the caption of figure 47 ... " Figure 47. Differential Input Configuration Using the ADA4938-2 " While the OpAmp shown is ADA4930-2.
Is there any difference between the part numbers ADA4938-1ACPZ-R7 and ADA4938-1ACPZ-R2 other than the sample ordering quantity?
The actual output impedance of the ADA4938 is not directly stated in its datasheet. However, also like an op amp, the ADA4938 has a low output impedance.
For the proper termination of the output of the ADA4938 to drive a signal through…
I'm planning to use the AD9255 single 14 bit ADC with DC coupled input signals in the dc - 20 MHz range.
Because of the DC coupled requirement I am looking at ADC driver amplifiers instead of a transformer.
The AD9255 web page recommends the ADA4937…
AD8138可以作为 ADC driver，但是其-3dB带宽只有320MHz，所以最好采用ADA4938-2