Will the THD of DAC be reduced by the clock frequency?

[edisonliu]

some question about dac

Will the THD be reduced according to the clock frequency if use sc resistor in the feed back loop of op for charge driven dac?
Some person said the THD is increased with the low pass filter frequency fLPF.It seams that the THD Will the be reduced according to the clock frequency.Is it true?
Have you some material about how to analyse the THD for charge driven dac? Especially for the clock frequency and GBW of OP.

 

[edisonliu]

Re: some question about dac

What will affect the THD of DAC?

 

[hubert008]

some question about dac

nonlinear affect the THD of DAC

 

[yibinhsieh]

Re: some question about dac

Some person said the THD is increased with the low pass filter frequency fLPF

This is because the output of DAC is a step voltage not linear voltage.

In other words, the output of DAC contains the high frequnecy components of the desired signals. Therefore we need a LPF filter to filter out these unwanted signals.

Thus, the higher LPF frequency the worse the THD of the DAC.

Yibin.

 

[edisonliu]

Re: some question about dac

But I think the second harmonic distortion will not be reduced by increasing the Flpf.In fact the second harmonic distortion is the main one.
How about the GBW affect the THD?
Thanks!

 

[laglead]

Re: some question about dac

I think GBW has the same effect as LPF bandwidth.

 

[edisonliu]

Re: some question about dac

Can you give the reason?