mordak
Member level 5
Hey guys
I have a problem with current steering DAC. I'm designing a continuous time delta sigma ADC and using this type of DAC in my ADC. After designing the whole ADC with ideal components tried to replace ideal parts with real ones. But after replacing the ideal DAC with the real one, the SNR of the ADC was screwed. I had an idea that it could be because of the switches. So to I replaced all real unit current DACs with ideal current sources and then just used real switches (M3P and M3M in the below pic). Still I could see some distortion, then I added dummy switches, but it also couldn't help. I attached fft of the entire ADC output. I appreciate if someone helps me to find a solution!
Thanks
The current DAC I used is like this one, but without M4.
and this is the SNR of the ADC, after and before using the DAC. Besides, size of the switches (M3P and M3M) is almost minimun possible size.
I have a problem with current steering DAC. I'm designing a continuous time delta sigma ADC and using this type of DAC in my ADC. After designing the whole ADC with ideal components tried to replace ideal parts with real ones. But after replacing the ideal DAC with the real one, the SNR of the ADC was screwed. I had an idea that it could be because of the switches. So to I replaced all real unit current DACs with ideal current sources and then just used real switches (M3P and M3M in the below pic). Still I could see some distortion, then I added dummy switches, but it also couldn't help. I attached fft of the entire ADC output. I appreciate if someone helps me to find a solution!
Thanks
The current DAC I used is like this one, but without M4.
and this is the SNR of the ADC, after and before using the DAC. Besides, size of the switches (M3P and M3M) is almost minimun possible size.
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