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ADS8860: High bandwidth input Amplifier

Part Number: ADS8860

Hi team,

I have learned that driving a switched capacitor input SAR ADC need high bandwidth amplifier, which the INA device can't usually support.

Could you please explain generally why the high bandwidth amplifier? what's the consequence if we use the low bandwidth amplifier to drive the SAR ADC?

Best Regards,

Wesley Huang


  • Hello Wesley,

    Thank you for your post. 

    The high-bandwidth amplifier and the R-C "charge bucket" filter at the SAR ADC input work together to deliver charge to the internal sampling capacitors. The goal is for the applied input voltage to fully settle within the design's accuracy targets. Between ADC acquisitions, the high-bandwidth amplifier replenishes the charge across the input capacitor before the next acquisition begins. This is imperative to achieve the full performance of the SAR ADC.

    We have an entire training series available on this topic in TI Precision Labs - ADCs. You can learn more about how to choose the amplifier and R-C filter components by reviewing this material:

    Best regards,