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Error in AD9626 specs?

Category: Datasheet/Specs
Product Number: AD9626
Software Version: N/A

The datasheet specifies an aperture delay of 0.1ns.  For ADCs at 250Msps, this sounds too good to be true.

This is more than a subjective "too-good-to-be-true" perception on my side.  Looking at other ADCs in the same category (Standard High-Speed ADCs), I see:

For similar speeds:

  • AD9683, AD9250, AD9634, AD9642  (all up to 250Msps) — aperture time is 1ns
  • AD9434  (370Msps, 500Msps) — aperture time is 0.85ns

Even some of the faster ones:

  • AD9684, 500Msps — aperture delay close to 0.5ns
  • AD9695, at 1.3Gsps — aperture delay is close to 0.2ns  (at 625Msps, 0.16ns)

Even the AD9213, at 6Gsps or 10.25Gsps, specifies a 0.12ns aperture delay!!

Can you provide confirmation?  What is the aperture delay and aperture jitter for the AD9626?



Aperture delay is the difference in the delay associated with the analog path (i.e. buffer and SHA) vs the delay of the sampling clock that controls the switch in the SHA.  The analog bandwidth of the AD9626 buffer/SHA is 700 MHz so it is quite possible that this is close to that of the sampling clock delay.   I would assume that the datasheet specs are correct.