What to do with unused pins - Electronic Circuits Projects Diagrams Free

bryan · 28th December 2003, 07:57 PM

I am using a LM339 comparator in a PWM circuit. I am only using 2 of the available 4 comparators on the chip. Should I tie tjhe other pins to ground or just leave as is.

spuffock · 28th December 2003, 09:45 PM

tie the +pins to +rail and the - pins to- rail . This forces the output pins open circuit and ensures that unused outputs dont flap about and generate nasty spikes.

bryan · 28th December 2003, 10:08 PM

Thank you

Styx · 29th December 2003, 05:36 PM

Also if this is a surface mount chip on a PCB tie the inputs via resitors (if it is a devel board and space isn't as important). You never know when a spare comparator might come in handy and it is a pain lifting legs and soldering onto them

just my 2 cents.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

28th December 2003, 07:57 PM	(permalink)
bryan	What to do with unused pins I am using a LM339 comparator in a PWM circuit. I am only using 2 of the available 4 comparators on the chip. Should I tie tjhe other pins to ground or just leave as is.

28th December 2003, 09:45 PM	(permalink)
spuffock	tie the +pins to +rail and the - pins to- rail . This forces the output pins open circuit and ensures that unused outputs dont flap about and generate nasty spikes.

29th December 2003, 05:36 PM	(permalink)
Styx	Also if this is a surface mount chip on a PCB tie the inputs via resitors (if it is a devel board and space isn't as important). You never know when a spare comparator might come in handy and it is a pain lifting legs and soldering onto them just my 2 cents.