SN74AVC8T245: Unused I/O Pin Connection

hideyuki sakai

Part Number: SN74AVC8T245

Dear, Sir.

My customer will use only 5ch although SN74AVC8T245 has total 8ch.

I would like to make sure the unused I/O pin connection will be better.

The floating will be OK?

Best Regards,

H. Sakai

0 Karan Kotadia over 4 years ago

Hi,

The device has CMOS inputs. Floating CMOS inputs is not okay. You need to either tie the inputs to VCC or GND. Here is a FAQ that talks about this:

You can leave the outputs floating.

Thanks!

-Karan

0 hideyuki sakai over 4 years ago in reply to Karan Kotadia

Dear, Karan-san.

Thank you so much for your valuable advice.

The customer is going to use under bi-directional utilizing DIR pin.

The input & output will be swapped by DIR control.

What is the better unused such I/O pin connection?

Please give your advice one more time.

Best Regards,

H. Sakai

0 Clemens Ladisch over 4 years ago in reply to hideyuki sakai

Guru 243980 points

Just tie all unused pins to GND; this is valid for both inputs and outputs.

Logic forum