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AD7380 SNR at higher input frequencies?

Hi,

In the AD7380 datasheet (Figure 18) the SNR vs input frequency rolls off and there is no data provided above ~100 kHz. Is there a reason for this?

What kind of SNR could one expect for a signal at 1 or 2 MHz?

Thanks,

Christer

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  • Hi Christer,

            Figure 18 actually shows SNR across the range of frequency up to 200kHz. The reason for this was that the equipment used to gather the data is limited to until 200kHz. In terms of the SNR at input higher frequency data of the AD7380, verified some devices at 1.5MHz, across temperature and it is approximately to have an SNR of  ~74dB. Is there a target SNR performance that is a requirement in your application? The AD7380 has an oversampling feature that improves SNR performance. 

    Regards,

    Jonathan

  • Hi Jonathan,

    Thanks for the information. In my application I'm concerned about interfering/blocking signals, so I was hoping AD7380 could maintain ~90 dB SNR up to Nyqvist of 2 MHz (so oversampling is not an option). At 74 dB SNR it's comparable to most 14-bit ADC:s, so not really the game changer I was hoping...

    Sincerely,

    Christer

  • Hi Chister,

           You can do normal averaging oversampling with the AD7380 that is up to 32x OSR. Although this may have trade-off with the throughtput rate.

    Regards,

    Jonathan 

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