AD7134 phase matching

Question

Hi, 
 I'm reading the AD7134 datasheet and the channel to channel phase matching is listed as 1.5-3.3 ns and device-to-device phase matching is 10 ns. These values seem quite poor compared to e.g. AD7380 that lists its "Aperture delay match [between channels]" as 26-100 ps or ADAR7251 that lists its "Interchannel phase mismatch" as 0.04 degrees. 
 I understand AD7134 phase matching might not be great if each device has its own independent XTAL (like in Figure 100 in the datasheet), but would running multiple devices in slave mode with a common low-jitter 48 MHz XO improve things? Although to be honest I don't really see how it'd improve channel-to-channel performance within the same device... 
 Is AD7134 not suitable for (in my case) coherent sampling in radar applications? 
 Thanks! 
 Christer

Wa$iM · Accepted Answer

Hi Christer 
 your observations are correct, if we consider just the ADC's then for AD7134 the numbers arent great. But when we look at the whole signal chain these numbers are better as the mismatches induced due to the Anti-alias filter are no longer needed for AD7134(Inherent Anti-aliasing). but for the SAR architectures these numbers could be significant. 
 Please go thru these articles to understand better 
 https://www.analog.com/media/en/analog-dialogue/volume-54/number-2/ac-and-dc-data-acquisition-signal-chains-made-easy.pdf 
 https://www.analog.com/en/analog-dialogue/articles/ctsd-precision-adcs-part-3.html 
 Hope it helps, thanks)

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AD7134 phase matching