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ADS8344: Avoid floating signals on unused analog inputs

Part Number: ADS8344

Are simple resistor pull up / pull down / divider circuits suitable fo tie unused analog input pins? 

I understand there is a need to eliminate slew rate limitations, provide drive current and have suitable source impedance otherwise samples of adjacent inputs can be corrupted.  Require mid voltage (nom 1.65 V) on one unused input, and could use Vref or A_Gnd voltage on another. Due to space limitations, a resistor solution is preferred, but could incorporate op amp circuit if necessary. 

Vref is set at 3.3 V.  Vcc is 4.5 V.

  • Hello Andrew,

    If certain channels  are not being used on the ADS8344, then through the digital communicaiotns, they can not be converted. You can use the Control Byte, shown in table 3 of the datasheet, to be sure that the unused channel is not sampled (table 1).

    if you are worried about cross talk between the unused channel and the active channels, then the grounding them would be best. You may use a resistor near the device to ground, or you can also ground the the input directly near the device.

    Regards

    Cynthia