TCA9800: pull-up resistors

Yang Wu

Part Number: TCA9800

Tool/software:

Hi team,

the datasheet says "For proper device operation, no external current sources (pull-up resistors) must be used on the SDAB and SCLB ports", could you help me understand why can't add external pull-up resistors? thanks.

Best regards,

Yang

5 months ago

0 Tyler Townsend 5 months ago

TI__Guru 53978 points

Hi Yang,

Adding external PU resistors affects the current detection on B-side which may make the buffer unable to realize if current is being sourced vs. sinked which affects the direction control of the buffer.

In short, TCA9800 with PU resistors on B-side may cause a logic LOW to not propagate across the buffer therefore we recommend to remove them.

Regards,

Tyler

0 Yang Wu 5 months ago in reply to Tyler Townsend

TI__Expert 3470 points

Hi Tyler,

I see. thanks for your help.

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TCA9800: pull-up resistors