• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 2 answers
  • Subscribers 34 subscribers
  • Views 289 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TCA9803: Connecting VCCB to EN Pin

TCA9803: VCCB Pull up

Taku Murayama
Intellectual 1830 points
Part Number: TCA9803

If the voltage of VCCB and the supply voltage of the slave side IC are the same, is it correct to use without pull-up from the figure shown in the data sheet?

  • 0
    Guru 316690 points

    The TCA980x does not work with pull-up resistors on the B side. Therefore, the supplies of the B-side slaves must always be at least as high as VCCB.

  • 0
    TI__Mastermind 47328 points

    Hi Taku,

    TCA980x uses an internal current source (ICS) on the B-side. This current source provides a pull-up current as well as direction control for the TCA9803 when driving from A-side to B-side, and B-side to A-side. Pull-up resistors are not allowed on B-side, as this device is sensitive to external sources of current on the B-side. Adding pull-up resistors on the B-side could affect the way this device behaves with its direction control circuit, therefore it is strongly recommended to not have pull-up resistors on b-side. 

    Regards,

    Tyler