TRSF3221E: RS232 interface - short protection

Erez Aharonov

Part Number: TRSF3221E

Hi,

I am considering using the TRSF3221E, but I need a short protection on its output.

The TRSF3221E typical short current is +/-35mA.

Is that mean I need to add series resistor of ~150ohm?

Or should I use additional protection IC.

If additional protection IC is needed, could you please advice me on one?

Additional question,

Do you have any mux or analog switch which can be fed by 3.3V or 5V for RS232 interface?

Thanks!

Erez.

0 Clemens Ladisch over 2 years ago

Guru 317370 points

In general, the RIN/DOUT pins do not need additional protection. The absolute maximum ratings do not specify a current limit.

Why do you think that 35 mA would be a problem?

There are no switches that can support RS-232 voltage level without high-voltage, bipolar supplies.

0 Erez Aharonov over 2 years ago in reply to Clemens Ladisch

On the TRSF3221E Electrical Characteristics, Driver section it is written that IOS=+/-35mA.
Do I have to limit this current using external resistor?

Thanks
Erez.

0 Clemens Ladisch over 2 years ago in reply to Erez Aharonov

Guru 317370 points

This entry says that when you short the output (i.e., force it to 0 V), a current of typically 35 mA will flow.

0 Erez Aharonov over 2 years ago in reply to Clemens Ladisch

Thank you for the clarification.

Regards,
Erez

0 Parker Dodson over 2 years ago in reply to Erez Aharonov

Hi Erez,

Clemens is correct on the question - if you have any additional questions please let me know!

Best,

Parker Dodson

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