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TCA9803: Application questions about TCA9803

Zach Zhu
Intellectual 2110 points
Part Number: TCA9803
Other Parts Discussed in Thread: P82B96

Tool/software:

Hi,

Custiomer now have a cable product application, and the transmission distance on the I2C bus needs to be larger than 7m. They want to use TCA9803 on the host pcb and the device pcb and want to know if application is feasible?

1. Is this cascade method feasible? What is the longest transmission distance?

2. If it is feasible, how to connect it? If not, recommend a new connection method or recommend a new device and application

BR,

Zach Zhu

  • 0
    TI__Guru 53278 points

    Hi Zach,

    TCA9803 B-side cannot connect to a B-side of another TCA9803 due to the internal current source present in the device. 

    It is also not recommended to have the ICS face the long cable side due to the inductive parasitic that the ICS would face. 

    An improved approach to this is to use a pair of P82B96 for long distance communication. See the device I linked. 

    If estimating 1 cm = 1 pf , then 7 m = 700 cm = 700 pF. The P82B96 would be more suitable for this type of application. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    TI__Intellectual 2110 points

    Hi Tyler,

    Thanks for your advice!

    Vcc can be chosen between 2V and 15V. If use 3.3V as Vcc, will it have any impact on current applications like communication distance, noise margin, etc?

    BR,

    Zach

  • 0 in reply to Zach Zhu
    TI__Guru 53278 points

    Hi Zach,

    The electrical characteristics across the VCC range of 2V to 15V are relatively consistent. VCC = 3.3V shouldn't affect the drive distance between the pair of P82B96's. 

    Regards,

    Tyler