This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Hi,
the datasheet says that the input clock frequency works with a range of 0.5 to 65 MHz.
How is this correlated to the sampling rate of 65 MSPS?
Is it something like this:
Thanks for help.
Hi Simon,
Yes, for this device a 1 MHz input clock frequency represents a 1MSPS sample rate.
Regards, Chase
Hi Chase,
thanks for the reply! But a further question for my understanding.
If I use the ADC3683 (65MSPS) can I only sample with 65MSPS or could I also slow it down to i.e. 50 MSPS by using a 50MHz clock?
And the other way round, if I'm using the ADC3681 (10MSPS) can i speed it up to 20MSPS with a 20MHz clock?
Hi Simon,
If you are using ADC3683 (rated for 65MSPS) you can sample at lower sampling rates such as 50MSPS without issue. The opposite is untrue, meaning the ADC3681 (rated for 10MSPS) cannot sample at 20MSPS.
Regards, Chase
thanks now I got it completely. I was a bit confused due to the fact that the datasheet is for a all three versions.
So if I exchange one ADC with another I also have to change the clock frequency.
Actually what would happen if switch the ADC from ADC3682 to ADC3681 and forgot to change the clock frequency from 25 to 10 MHz? Would it also work and just sample with 10MSPS?
Sure, no problem!
If clocked at higher speeds, the device won't become damaged, but it will simply not work past some certain limit - which will be a device to device limit so I cannot tell you exactly where the ADC will no longer work. With that being said, if any devices do actually work at this '25MSPS', the performance will not be as shown in the datasheet but would be much, much worse.
Thanks, Chase
Actually what would happen if switch the ADC from ADC3682 to ADC3681 and forgot to change the clock frequency from 25 to 10 MHz? Would it also work and just sample with 10MSPS?
No, there is no internal PLL or synthesizer which creates the max sampling rate if a clock greater than the max is applied. As a result, the device will try to sample at 25MSPS which may or may not work as described in the post above.