ADS7951-Q1: increase the input filter cap from 150p to 1nF

Wu JW

Part Number: ADS7951-Q1

Hi, Team,

My customer want to increase the input filter cap from 150pF to 1nF to avoid the system noise. Is there any risk for this application? We can't find any suggestion for this cap, pls help check it. Thanks!

over 3 years ago

0 Collin Wells over 3 years ago

TI__Guru 62895 points

Hello JW,

The external components are largely dependent upon the driving circuitry.

You'll need to make sure any amplifiers involved can drive the increased capacitance and that the source can also recharge the capacitor properly before the subsequent acquisition begins.

Here are some helpful videos on the subject of SAR ADC drive:

https://training.ti.com/node/1139106?context=1139747-1140267-1128375-1139106

If they're not using a driver amplifier, this video is particularly helpful.

https://training.ti.com/ti-precision-labs-driving-sar-without-amplifiers

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ADS7951-Q1: increase the input filter cap from 150p to 1nF