What can I expect from exceeding the maximum system clock rate in the data sheet by 1% to 10%?
The maximum system clock rate specification in some ADI DDS’s data sheets can be conservative. You may be able to run some faster however there’s no performance or lifespan guarantees operating above the max limit in the data sheet. So, if you over clock an ADI DDS part, you do so at your own risk.
Typically the two outcomes from over clocking are spectral degradation and/or running the die temperature too hot. Spectral degradation is usually a violation of internal timing requirements (internal setup and hold times). The spectral noise floor can drastically alter as a result.The increase in system clock rate also causes an increase in power dissipation which raises the die temperature. This temperature rise can be calculated by the following formula: Tdie = Tambient + PWR(Theta JA). You should not exceed the maximum junction temperature specification, which is typically 150C.
In addition there any may be hardware DDS internal limitation Fclk, so more then possible it blocked. Noted by my experiments, and AN_s of ADI.
fail-safety loose are you ready - you do so at your own risk.
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