SN751178　Fail　Safe

Masa_0000

Intellectual 885 points

Other Parts Discussed in Thread: SN751178, SN75117

Hi Everybody!

I have a question about Internal "Fail Safe function" of SN751178 (RS485 Driver & Receiver).

I found Data Sheet (Page 1 ) that described "internal Fail Safe function" .

"Fail-safe design ensures that if the receiver inputs are open, the receiver outputs always will be high."

Is this mean it has "internal Fail Safe function" ?

Please reply for me if you have any information.

Best Regards

Shing

over 9 years ago

0 Andrew Leverette over 9 years ago

TI__Intellectual 1190 points

Failsafe can be implemented from the transmitter or the receiver. transmitter failsafe is when pullup and pulldown resistors are applied on the bus to set the bus polarity.

receiver failsafe is when the receiver outputs a defined high state when the input pins are left floating.

0 Masa_0000 over 9 years ago in reply to Andrew Leverette

Intellectual 885 points

Hello Andrew Levertte.

Thank you for your quickly reply.

May I have confirm your information?

SN75117 case:

It has internal Fale Safe function.

If Open fail case then output is High.

SN75118 case:

It has not "internal Fale Safe function"?

If Open fail case then output is "indeterminate"?

Is my understandings true or fault ?

Best Regards

Shing

SN751178_FailSafe.pdf

0 Andrew Leverette over 9 years ago in reply to Masa_0000

TI__Intellectual 1190 points

Yes, you are correct. Indeterminate is the same as high impedance. Just an unknown output.

0 Masa_0000 over 9 years ago in reply to Andrew Leverette

Intellectual 885 points

Thank you very much for your kindly cooperation.
I under stood it.

Best Regard
Shing

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SN751178　Fail　Safe

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SN751178 Fail Safe

SN751178　Fail　Safe