I agree with all the previous posts, it is best to show the power pins.  I
mostly use the Protel supplied library symbols only for caps, resistors,
etc.  For most ICs, I make my own symbols.  For discrete logic, I create a
separate part for the component that is a power block (a square with the
power and ground pins shown).  So, a quad NAND gate would have 5 parts, the
4 gates and a power block.

This way it does not clutter the logic schematic as much.  I can put the
power blocks off to the side or even on a separate page.  I show any bypass
caps associated with the parts at their power block.  This allows the
schematic to indicate where we want the caps physically located on the PCB
(ala C46 connects to U12-14).  We started doing this when making symbols for
large scale digital chips that have a multitude of supply pins.

I also show everything that has a connection on my board on the schematic:
mounting holes, shields, test points (except one customer who puts a TP on
every net for In Circuit Test).

When I get a clean DRC, I can be confident that nothing was overlooked.  I
have worked the other way, ending up with DRC errors and checking them off
to make sure they are all were there for a reason.  Inevitably, one will
slip thru and bite you (usually at the worse possible time).

My 2 cents....


Cliff Gerhard, P.E.
Director - EE Group
E-M Designs, Inc.
32122 Camino Capistrano
Suite 200
San Juan Capistrano, CA 92675
PH 949.661.3016 x 501
FX 949.661.3017

-----Original Message-----
From: Dave Babcock [mailto:[EMAIL PROTECTED]]
Sent: Friday, November 30, 2001 7:15 AM
To: Protel EDA Forum
Subject: [PEDA] Using Multiple Vcc for same part


I am using some logic gates that require a different Vcc value in different
areas of my circuit.  For example, a fairchild 74VHC00 that I need 5V at one
location and 3.3V elsewhere.
Since Vcc is a hidden pin it is showing up on the same net.   Any way to get
around this in schematic or do I need different library parts with different
names for the Vcc pin.
Dave Babcock
Chief Engineer
Cardinal Components, Inc.
Phone: 973-785-1333x565
Fax: 973-785-0053

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