I am designing a circuit which reads a analog signal(DC - Response from a photo-diode exposed to tungsten lamp) to a 12 bit ADC. The ADC is MCP3202 running at 1Mhz speed and uses 16 input bits to get one sample of the result.
As per my calculations, I have calculated the response time of the low pass filter as shown below:
Chip Speed (Mhz) 1 Period(us : microSecond) 1 No of Process Cycles 16 Response time required (us) 16 Response time required (ns : NanoSeconds) 16000 Response time required (ms : MilliSeconds) 0.016 Response time required (Seconds) 0.000016 or 1.6E-5
I believe that if my RC circuit is slower than the above response time, then I will see a delayed response, which I should avoid. Therefore, I choose the following Resistance and Capacitor values for my RC low pass filter.
R = 1 K C = 5 nF
The cut-off frequency is calculated as :
fc = 31830.9886184[Hz]
The response time is calculated as:
Does all of the above sounds OK or am I off track here?