spring1860
Member level 5
hi
i'm confused about this active lowpass filter(see the attachment) , this filter is used in the front of a CLASS D audio amplifier
R3=R4=2R1=2R2=300K
C1=C2=14pF
Cs=28pF
The AMP has a 75dB DC gain, 26.7MHz UGB , 72.6(deg) PM 。
The AC response of the filter is shown in the attachment too. the red curves is the response with Cs=28pF, the yellow curves is the response without Cs (Cs=0).
The difference occurs on high frequency (relative to w-3dB), i think it dosn't affect the performance of the CKT ( PLZ correct me if I am wrong).
And i problem is why we need the cap. Cs ,
i'm confused about this active lowpass filter(see the attachment) , this filter is used in the front of a CLASS D audio amplifier
R3=R4=2R1=2R2=300K
C1=C2=14pF
Cs=28pF
The AMP has a 75dB DC gain, 26.7MHz UGB , 72.6(deg) PM 。
The AC response of the filter is shown in the attachment too. the red curves is the response with Cs=28pF, the yellow curves is the response without Cs (Cs=0).
The difference occurs on high frequency (relative to w-3dB), i think it dosn't affect the performance of the CKT ( PLZ correct me if I am wrong).
And i problem is why we need the cap. Cs ,
