Part Number: ADS1274 Hi, In my application I'm using the ADS1274 , 24- BIT Analog to Digital Converter. Due to limited PCB space, I'm thinking of giving up the pre amplifiers that drives the input switched capacitor to all four inputs and the reference too. In addition, I want to work with low clk frequency (100kHz), all 4 channels will be active, CLKDIV will set to '1' and with RC input filter (the output rate will be ~39SPS). In order to do that, I need to have a better understanding about the effective input impedance of etch input and the reference. According to the formula in Figure 69 and with the given parameters, Is it true to say that the effective impedance in my case will be: 14kohm*6.75MHz/Fmod while Fmod=Fclk/40=100kHz/40=2500Hz-> Zeff=14kohm*6.75MHz/2500=37.8Mohm? – Almost no effect as combined with the external input RC filter. I think I'm wrong about the 6.75MHz in the formula… What is the source of this number? Does this number is somehow related to the 27MHz/ 5.4MHz clock in the datasheet reference? (That not relevant in my case because I'm using a 100kHz clock) Thanks, Idan
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