Data converters

Data converters forum

ADS1299: ADS1299: Daisy chain termination - Ground required or optional?

Stephen Hastie1

Prodigy 70 points

Part Number: ADS1299

Hi,

When using ADS1299s in a daisy chain configuration, does the final ADS1299 in the chain require DAISY_IN to be connected to ground? Would I have any issues if this pin was left floating?

Cheers,

Stephen

over 5 years ago

0 Praveen Aroul over 5 years ago

TI__Mastermind 49956 points

Hello Stephen,

Thanks for reaching out regarding the ADS1299.

Due to US Thanksgiving holidays, our responses are delayed.

We will provide a response to your queries next week in the order in which it was received.

Thanks for your patience and understanding.

0 TCT over 5 years ago in reply to Praveen Aroul

TI__Genius 11550 points

Hi Stephen,

It is recommended to tie the DAISY_IN pin to digital ground for the last device or if it is not used to avoid any noise coupling that might cause erroneous data in the daisy-chain.

Thanks.

-TC

0 Stephen Hastie1 over 5 years ago in reply to TCT

Prodigy 70 points

Hi,

I'm planning on have multiple cards with ADS1299s and any card could have the last ADS1299 in the chain. Could I use a weak pull down resistor on DAISY_IN for the last ADS1299 on each card?

Cheers,

Stephen

0 TCT over 5 years ago in reply to Stephen Hastie1

TI__Genius 11550 points

Hi Stephen,

I understand the hardware requirements for such a system design. It should be fine with the weak pull-down resistor. Please refer to the thread below for more information on the pull-down resistor.

https://e2e.ti.com/support/data-converters/f/73/t/907557

Thanks.

-TC