AFE5832LP: Swaroop AFE Input Termination

Craig Lindholm

Part Number: AFE5832LP
Other Parts Discussed in Thread: AFE5832, TX7332

Hello.

We are using the AFE5832 with the TX7332 on our new design which is based loosely on your Swaroop reference design.

In your reference schematic page 4 ( MED1426_REV1P0-SCH.pdf ) you have 200ohm termination on the AFE inputs, yet the TX7332 has a 24ohm on resistance ( page 12, SBOS851_TX7332 - Full Datasheet )

Our transducers are usually in the 1k - 5k ohm impedance range. How is the termination impedance determined on the AFE I/P? Is it based on the TX7332, or the combined impedance of the transducer AND the TX7332?

Craig

over 2 years ago

0 Abhishek Vishwa1 over 2 years ago

TI__Expert 6790 points

Hi Craig,

Thanks for your query.

I have assigned this thread to Shabbir and you will hear from him on this soon.

Thanks & regards,

Abhishek

0 Shabbir Amjhera Wala over 2 years ago in reply to Abhishek Vishwa1

TI__Expert 4481 points

Hi Craig,

200 ohms resistor in Swaroop board is just a place holder. This termination option is coming from signal integrity point of view. From AFE side, there is no constraint. Ideally no termination is best for SNR performance however not having termination can lead to signal integrity issues. So customer can choose the termination value based on cable/transducer characteristics impedance. For you case I see transducer impedance is high in range of 1k-5k ohms. In that case i recommend to try system performance without termination. If you dont have very long cables connecting TX7332 to transducer, then signal integrity will be ok.

Regards,

Shabbir

0 Craig Lindholm over 2 years ago in reply to Shabbir Amjhera Wala

Prodigy 100 points

Awesome, Thanks Shabbir!

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AFE5832LP: Swaroop AFE Input Termination