ADS8688A: charge bucket fitler is required for this ADC?

Noriyuki Takahashi

Part Number: ADS8688A

Hi team,

In general, is the charge bucket fitler required for this ADC?

I think SAR ADCs usually require the filter for better ADC performance, but not sure the fitler is required for this kinds of ADCs integrating buffers.

And I also want to confirm the aquisition time that the we need to wait by the input signal setlte within 1/2LSB.

Regards,

Noriyuki Takahashi

over 1 year ago

0 Noriyuki Takahashi over 1 year ago

TI__Genius 9830 points

Hi team,

This is just a reminder.

Could you help this?

Regards,

Noriyuki T

0 Ryan Andrews over 1 year ago in reply to Noriyuki Takahashi

TI__Guru 60476 points

Hello Takahashi-san,

The ADS8688A integrates the required circuitry to drive the sample-and-hold circuit, so the input pins are high-impedance. No external charge-bucket is required. Only a low-pass filter would be needed to limit out-of-band noise, depending on the application requirements.

Regards,

Ryan

0 Noriyuki Takahashi over 1 year ago in reply to Ryan Andrews

TI__Genius 9830 points

Ryan,

Thanks. So does this mean that the input singal should settle within 0.5LSB by the minimum acquisition time during the acquisition phase?

Regards,

Noriyuki Takahashi

+1 Ryan Andrews over 1 year ago in reply to Noriyuki Takahashi

TI__Guru 60476 points

Hello Takahashi-san - yes, that is correct. The integrated driver ensures complete settling during the acquisition phase. The ADS8688A also ensures complete settling whenever the multiplexer transitions from one channel to another.

Regards,

Ryan

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ADS8688A: charge bucket fitler is required for this ADC?