Hi Team,
My customer want to design 1st low pass filter as anti-aliasing for differential input of ADS8422.
Do you have any tool or software to design such the filter or do you have any document describing how to design?
I'm not familiar with differential filter so please lecture how to design if possible.
Regards,
Takashi Onawa
Hello Takashi-san,
A first order differential low pass filter is very similar to a single ended filter. For example, if the customer wants to set a corner frequency of 1MHz, the following circuit equation can be used.
F3db=1/[2*pi*(R1+R2)*Cdiff]
Choose Cdiff=1nF
R1=R2=79.6ohm
The above filter frequency assumes high input impedance inputs. The ADS8422 will still need amplifiers to drive the inputs to get datasheet performance. Please refer to Figure 32 in the ADS8422 datasheet.
The TI Filter Design Tool can be used to calculate the component values for different frequency responses.
https://webench.ti.com/filter-design-tool/
Regards,
Keith Nicholas
Precision ADC Applications
