ADL5565 Common-mode Rejection Ratio

Question

The data sheet shows common-mode rejection ratio on page 14, figure 24 as 57 dB at 1GHz. 
 Using the s-parameters given for the device shows a common mode gain of approx -32 dB in the 6 dB gain configuration at 1GHz. The same simulation shows approx. 6 dB of differential gain, so I believe the simulation is set-up correctly. 
 How was the common-mode rejection ratio measured? Can I expect CMRR around 57 dB at 1GHz? I will be using the device in a circuit that will have a significant common-mode RF signal that I want to reject.

ADIApproved · Accepted Answer

Hi, 
 Yes, I see about the same as you for CMRR when using the published S-parameters. I'm getting around 43 dB of delta between differential vs common mode. The datasheet value of 60 dB typical CMRR appears to be incorrect, my apologies. 
 Are there other important specs for your application, such as OIP3, HD2/3, etc ? If you can share more details of the application we may be able to suggest a more suitable part number. 
 Thanks, 
 Darrell

Electronic Design Services - PartnerZone

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ADL5565 Common-mode Rejection Ratio

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