ADS127L18: Input circuit for pseudo-differential

Shinichi Inoue

Guru 21841 points

Part Number: ADS127L18
Other Parts Discussed in Thread: REF6225, OPA320, OPA392, OPA863A, OPA210

Tool/software:

Dear Specialists,

My customer is considering ADS12７L18 for pseudo-differential input.

I would be grateful if you could advise.

ｰｰｰ

Regarding the analog input section of the ADS127L18, I plan to use all 8 channels as pseudo-differential.

I am wondering what the AINN/AINP peripheral circuit should be.

Could you please provide a recommended circuit.

(1) I am considering a method to distribute the VCM output, so could you please let me know how can I use it for 8 circuits?

(2) Is there any other circuit you can recommend?

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I appreciate your great help in advance.

Best regards,

Shinichi

2 months ago

0 Keith Nicholas 2 months ago

TI__Mastermind 47670 points

Hello Shinichi,

You can connect the AINNx inputs together and drive from a single 2.5V reference, such as the REF6225 or REF54250. For the AINPx inputs, a low noise and distortion precision op amp can be used, such as the OPA863A, OPA320 or OPA392.

If you already have a system reference and you simply need a buffer to drive the AINNx inputs, you can use the OPA210 and the circuit for the VCOM buffer used on the evaluation board.

https://www.ti.com/lit/ug/sbau435/sbau435.pdf

Regards,
Keith Nicholas
Precision ADC Applications

0 Shinichi Inoue 1 month ago in reply to Keith Nicholas

Guru 21841 points

Hi Keith,

Thank you for your reply.

I shared your answer with the customer.

Just in case, could you please provide the circuit example of pseudo-differential input.

The actual circuit is helpful.

I appreciate your great help and cooperation.

Best regards,

Shinichi

0 Keith Nicholas 1 month ago in reply to Shinichi Inoue

TI__Mastermind 47670 points

Hello Shinichi,

Example of pseudo-differential input. I hope this is helpful. Please let me know if you have any additional questions.

Regards,
Keith

0 Shinichi Inoue 1 month ago in reply to Keith Nicholas

Guru 21841 points

Hi Keith,

Thank you for your reply.

I'll share this with the customer.

I appreciate your great help and cooperation.

Best regards,

Shinichi

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ADS127L18: Input circuit for pseudo-differential