• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 32 subscribers
  • Views 255 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

SN65C1168E-SEP: ISOS141-SEP and SN65C1168E-SEP based on App Brief SLLA556, unused pins and general guidelines.

Pedro Arango Ramirez
Prodigy 20 points
Part Number: SN65C1168E-SEP
Other Parts Discussed in Thread: ISOS141-SEP,

Hello, 

I am trying to use the ISOS141-SEP in conjunction with the SN65C1168-SEP to create an RS-422 rated UART transceiver system. The main reason these parts were chosen was due to the existing App Brief and the need to shift the voltage down from 5V to 3v3 so that our Microcontroller could interface with it.

However, I need some assistance to understand what to do with the unused pins, wither to ground them or tie them up with a 10k. 

Our Schematic

The reference circuit:

App brief location: 

Space-Grade, 30-krad, Isolated RS-422 Serial Transceiver Circuit (ti.com)

Please do let me know what yo do with the unterminated connections to make sure that the devices will work as intended together. Specifically:

SN65C1168E-SEP

  • 2Y
  • 2Z
  • 1B
  • 1A
  • 1R

ISOS141-SEP

  • INC

Best,

Pedro Arango Ramirez

  • +1
    TI__Mastermind 45917 points

    Hi Pedro,

    For the Sn65C1168E-SEP:

    2Y - can be left floating

    2Z  - can be left floating

    1B - can be left floating (weak integrated pull-down resistor will pull 1B toward ground when left floating)

    1A - can be left floating (weak integrated pull-up resistor will pull 1A toward VCC when left floating ) 

    1R - can be left floating - it should just be outputting  a DC level that is ~VCC so you don't need to do anything additional here. 

    For the ISOS141-SEP - you should be able to leave INC floating because the default output on "OUTC" should be low - and the '2D' pin on the SN65C1168E-SEP will require a default level on the pin - either high or low - so a default low is okay.

    Please let me know if you have any other questions!

    Best,

    Parker Dodson