How to connect a component with multiple of the same pin

Thread Starter

jlawley1969

Joined Feb 22, 2021
18
So say I have a IC where it has 3 of the same pin. For example a surface mount MOSFET with 3 pins for the source and they are all going to a single pin on something else. Would I run 3 seperate traces to the 1 pin or combine 3 to one large trace to the 1 pin. Does it matter? Do I need to use all the 3 pins?
 

dl324

Joined Mar 30, 2015
12,873
It depends on how the device is being used. Is it a high power device operating at low current? High current? Near the maximum current supported by the device?
 

Thread Starter

jlawley1969

Joined Feb 22, 2021
18
It depends on how the device is being used. Is it a high power device operating at low current? High current? Near the maximum current supported by the device?
Well I want to know what to do for either case. I have many components on my board all at different power levels
 

BobaMosfet

Joined Jul 1, 2009
1,780
@jlawley1969
Well, instead of being vague- let's get a pic or a part number, so we can pull the datasheet.

Yes...yes... I'm a datasheet nazi. Facts! Figures! Perils and naughty things done to electrons to make the suffer under the bondage of voltage restraints!!!

"HA! HA! HA! - HO! HO! HO! - HEE! HEE! HEE!" --The Evil Time-Lord, Chronos*


---
*Hopefully somebody can remember the name of that game- one of the very first attempts at outputting voice over audio on a PC... and it was just garbled noise until you trained your ear to understand what was being stated.
 

Thread Starter

jlawley1969

Joined Feb 22, 2021
18

crutschow

Joined Mar 14, 2008
27,243
i honestly thought there would be at least SOME general guide lines
Here's one:
In general you just tie them all together with one fat trace (which can then feed to a narrower trace, if desired).
Typically there is more than one pin for the same connection to reduce pin impedance (and perhaps maximum current capability per pin if it's a high current device).
 

Ian0

Joined Aug 7, 2020
2,289
If it's a power transistor, then there are two, three or four pins, because one on its own can't take the current.
Also, it may be to help get the heat away from the device to the circuit board- have a look at the datasheet and it may tell you how large and area of copper it should be soldered to.
If it's a small-signal device, then there may be extra 0V pins to prevent interference between signals.
 
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