ADS7138-Q1: DESIGN REVIEW

Hello,

We are working on a project with ADS7138QRTERQ1 in it.
Kindly review the attached schematics and let me know the review comments.

ADS7138QRTERQ1_SCH_28DEC2020.pdf

Hi Melbin,

I did not see any obvious error in the schematic, however following suggestions can make your circuity better:

1. Add a capacitor between the ADC's input and ground to have a RC filter for filtering noise.

2. For channels without a resistor divider, use a certain value resistor instead of 0ohm(R2673/2674/26742676/2678/2679) with a capacitor to the ground as a filter. The series resistor can also limit input current to protect ADC.

3. Connect unused analog input pins to the ground.

4. If the actual sampling of the ADC is not high, you can drive the ADC without amplifiers, however it's important to select proper value RC for signal settling, check TI's Precision Labs ADC - Driving ADC without amplifiers for the details. If you are using an ADC to monitor a fast-moving signal with a higher sampling rate, you will need an amplifier to drive the ADC, check TI's Precision Labs ADC - SAR ADC Input Driver Design for more information.

Best regards,

Dale

Melbin,

I noticed that you have already posted this. In an effort to consolidate posts on E2E, I have merged the threads.

Best,

Danny

Thanks Dale,

Could you please suggest to me the value of the RC that need to provide in our case?

Hi Melbin,

The value of RC depends on the sampling rate, your signal voltage and so on. Check the details in the links I shared to you above.

Regards,

Dale