basic electronic question

[distropia]

Hi folks. I'm finishing a design in Eagle CAD but in one of the ICs I have 5 unused inputs + 5 unused outputs. I know is a good idea to tie that to gnd instead letting it floating.

My question is, do I have to use one pull-down resistor for each input and output line, or can I use one resistor for all the inputs and another for all the outputs?

thnx

 

[mikey]

What is the IC you're using? If all the spare inputs and outputs are isolated from what you're using, you can probably just leave them floating.

 

[distropia]

What is the IC you're using? If all the spare inputs and outputs are isolated from what you're using, you can probably just leave them floating.

the most unused pins are in a 74ls244 (10 pins!), but also in a LS27. I've read let them floating increase the chip consumption and thus can overheat and eventually die.

 

[distropia]

Just for the record, I just learned all the inputs in this ls244 can be tied to GND and the outputs can be left floating -they will be low-.

The answer to my question depends on every pin on every specific chip, the datasheet will tell if its advisable to (1) left floating (2) tied high (3) tied low (4) pulled high through a resistor or (5) pulled low through a resistor