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ADS7128: Does this device incorporate an buffer for the 4 analog inputs?

Bruce Poe
Prodigy 10 points
Part Number: ADS7128

Is there an input buffer on these two devices, TLA2528I  and  ADS7128, to isolate the A/D convertors from the outside world?  I am unable to find any reference in the data sheet.  I am scaling the input to the devices with a resistive divider and want to make certain that I will not be introducing an error with a 4.7k source impedance.

  • 0
    TI__Mastermind 24940 points

    Hello,

    The block diagram in the datasheet is an accurate representation of the device architecture. There is no integrated input in these devices. 

    Using resistor dividers to step down a high input voltage is a common use for this device. The measurement will be as good as the input signal, but any known error or deviation can be taken into account within the host device. 

    I suggest looking at the following short document: Driving a SAR directly without a buffer ~click here~, this will provide good generation information, though not specific to a resistor divider

     

    Regards

    Cynthia