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TS3A44159: TS3A44159 Surge

Guenther Mader
Prodigy 50 points
Part Number: TS3A44159
Other Parts Discussed in Thread: TS12A12511

Hello,

I'd like to use the TS3A44159 to switch between RS422/RS485 RX and TX (4 wire full duplex communication) for easier cabling. Switching between directions at the transciver is no option for me because of active EMI filtering. Since there may be EMI surges on the transmission line (EN61000-4-5 8/20µs) I'm using the ESD1014 for camping which has a maximum clamping voltage of 11V. That's the maximum input protection I can offer.

So may question:

Has the TS3A44159 any surge rating at the analogue input?

Or can you guarantee that the clamping is sufficient?

Thank's in advance and kind regards,

Guenther

  • 0
    TI__Mastermind 45340 points

    Guenther,

    The maximum recommended input voltage on the I/O pins is 4.3 V.  The abs max rating for the I/O pins is Vcc + 0.5 V.

    Exposing the I/O pins to 11V will be outside the abs max raising and may cause permanent damage according to note 1.  

    You will need a device that can support 11 V  such as the TS12A12511.

    Thank you,

    Adam

  • 0 in reply to Adam Torma
    Prodigy 50 points

    Hello Adam,

    thanks for your reply and the proposal!

    If I would go with the TS12A12511 the maximum rating would be violated anyway because Vcc remains at 3.3V and the IOs are rated only for -Vcc to +Vcc and therefore 11 V exceeds also this rating.

    But since surge ratings (if available) are always above the normal ratings because of the short surge duration, I  asked my initial question.

    It would also be intuitive to have a surge rating since "communication Systems" is listed under typical applications which are normally exposed to surges.

    Kind regards,

    Guenther

  • 0 in reply to Guenther Mader
    TI__Mastermind 45340 points

    Guenther,

    Do you have an example of device you are using today that supports 3.3V supply and can accept 11V signals?  We are always looking to make new parts that will help our customers.

    You can also implement external protection.  More information is found in this application note.

    System-Level Protection for High-Voltage Analog Multiplexers

    http://www.ti.com/lit/an/sbaa227/sbaa227.pdf

    Thank you,

    Adam