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May 18th, 2021, 3:15am
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Capacitive DAC Unit Cell Size in ADC (Read 71 times)
niloun
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Capacitive DAC Unit Cell Size in ADC
Apr 27th, 2021, 11:06pm
 
Hi everyone,

When we want to calculate ADCs sampling capacitor size we choose C such that thermal noise level is less (or equal) than quantization noise

KT/C<Δ2/12

Which leads to

C>12KT×22b/VFS2

My question is that if "C" here is the total capacitance of the capacitor array or unit cell capacitor? and why?

For example if in the case of an eight bit ADC we find C>20fF from C>12KT×22b/VFS2
should we divide 20fF by 28 to find the minimum unit cell size or C is the minimum unit cell size itself?
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« Last Edit: Apr 28th, 2021, 2:16pm by niloun »  
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