SN74LVC8T245: SN74LVC8T245 - Output state verification

Gopi Narayanan

Part Number: SN74LVC8T245

Tool/software:

Hi Team,

Good to initiate the communication here.

I am using SN74LVC8T245RHLR this part one of my design and as per the design my input as no defined state (DIP switch open condition) and output as PU resistor.

According to the design, is my output will affect when there is no defined input in the IC? Refer to below images

Thanks in advance!

Best Regards,

Gopi.

10 months ago

0 Clemens Ladisch 10 months ago

Guru 317360 points

The input is floating, so it will be either high or low or oscillating. When the input is read as low, the output drives low, overriding the pull-up resistor.

And there are other reasons to avoid floating inputs: [FAQ] How does a slow or floating input affect a CMOS device?

You should use a pull-up resistor on the input (and let the DIP switch pull down without a resistor).

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SN74LVC8T245: SN74LVC8T245 - Output state verification