SNR of AD7768-1 with AD8250 at 48 kHz input frequency


my customer asks for the SNR that is to be expected with the following signal chain:

48 kHz input-signal ---> AD8250 ---> LTC6363 ----> AD7768-1

AD8250 is powered by +/-15 Volt.
The LTC6363 translates the up to +/-10V output from the AD8250 into a differential signal convinient for the AD7768-1.

I know that the effective SNR depends on input-signal amplitude, AD8250 gain and AD7768-1 configuration.
Which configuration will give the best SNR at 48 kHz, and which SNR is achievable?

Looking forward to your answers.


Parents Reply
  • +1
    •  Analog Employees 
    on Dec 11, 2020 1:37 PM in reply to Niels

    Hi Niels

    You can do a RMS to calculate the overall noise.

    so from tool you got the system Noise of LTC6363-05 + AD7768-1 @ 32ksps to be 4.57uVrms

    LTC6373 noise @ G=1 is 18.7nV/sqrt Hz..@ 32ksps FIR BW is about 14kHz.

    So 18.7*sqrt(14k) = 2.2uV.. so total noise is sqrt(2.2*2.2 + 4.57*4.57) = 5uV

    coming to gain options .. +/-10V signal with 0.5 gain = +/-5V signal @ LTC6373 output and you can always use 5V reference


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