input impedance when routing through SARMUX to internal CTBm op-amp then to SARADC? | Cypress Semiconductor
input impedance when routing through SARMUX to internal CTBm op-amp then to SARADC?
I see in the TRM (Figure 19-6 on page 203) that it's possible to route an analog input into a CTMb opamp configured as a follower and then into the SAR ADC. I also see that the additional switches slow things down such that 1Msps isn't possible, but there isn't any mention of how this affects the impedance that the driver of the analog signal sees.
The SAR ADC input impedance is pretty "sloppy"; I am hoping to use the CTMb op amp to present a very high input impedance to the analog source. What would the input impedance of one of the CTMb pins be in this kind of configuration? Is there a better way to configure the PSoC4 to have a number of high-impedance analog inputs which are then sampled by the SAR ADC?