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LM556 unused half input termination

Crossposted to sci.electronics.design,sci.electronics.basics ; followups-to set to sci.electronics.basics.

I found a 556 in my junque box, and thought it'd be fun to flash an LED or something, but I only need one half of it. I know unterminated inputs are anathema for digital chips, but what about the spare half of a 556? From the schem. on the data sheet,

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it kinda looks like pulling them to either rail might be not too good for the chip - what do you guys recommend?

Thanks! Rich

Reply to
Rich Grise
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I think anything within the datasheet supply rails is allowable to all input pins.. Don't connect the output pin and the open collector to anything.

In a low current app,look at the datasheet to find out if a L or H to the inputs consume more or less current. It might be possible to leave all pins loose if the internal op amps are not switching to input buzz pick up.. (It's not CMOS.) It might consume a tiny bit more current if stuff is switching without purpose.

D from BC

Reply to
D from BC 

--
It\'s bipolar so no big deal, but if I wanted to nail everything down
I\'d run THRESHOLD and RESET low, TRIGGER high, and let the rest of
it float.
Reply to
John Fields

sheet,

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Tie the inputs together and have the output go through a large resistor, like 100K to ground. That should do the trick nicely.

Reply to
Coleston

Only so far as they affect the output.

Just tie Reset (actually !RESET) low.

Reply to
JeffM

Thanks everyone for your answers. Now all I have to do is get up off my dead butt and breadboard the thing. :-)

Thanks! Rich

Reply to
Rich Grise

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