SN74AVC4T774: Unused pins if DIR pin is connect to GND

Sagar Kumar

Prodigy 30 points

Part Number: SN74AVC4T774

Hi Ti team

If i connect PIN#5, 6 to GND and pin#9, 10 GND, do we need to connect pin 3 and 4 to GND or can we leave it float?

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 283620 points

Unused outputs can be left open. (But it would not hurt to ground them.)

0 Sagar Kumar over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

IO/P will get logic 0 then without connection them to GND then what is real advantage are getting to connect with GND?

Due you have insights about that? might be some leakage current reduction?

0 Clemens Ladisch over 2 years ago in reply to Sagar Kumar

Guru 283620 points

In this circuit, there is no advantage. It does not matter.

0 Jack Guan over 2 years ago in reply to Sagar Kumar

TI__Mastermind 27451 points

Hey Sagar,

One advantage of connecting unused I/O to GND is to ensure that the I/O is forced to a known voltage. See this app note for more information.

Regards,

Jack

0 Sagar Kumar over 2 years ago in reply to Jack Guan

Prodigy 30 points

Hi Jack,

I agree with you but if i already make DIR pin Grounded then we can leave A side is Open A3 and A4pin. Please check below image and let me know in this scenario we will get any advantage by making A3 and A4 grounded?

0 Jack Guan over 2 years ago in reply to Sagar Kumar

TI__Mastermind 27451 points

Hey Sagar,

The advantage to grounding A3 and A4 to GND while DIR3 and DIR4 are grounded is to set that node to a known voltage. It is just good practice, but as Clemens' stated- outputs can be left open (DIR pin set to L means direction of signals is from B to A)

Thanks,

Jack