Actions
Forum Thread Details
  • Replies 4 replies
  • Subscribers 178 subscribers
  • Views 314 views
  • Users 0 members are here
Related

When PWR is not the same PWR

autodeskguest

I have two instances of an op-amp that must be connected to different

+15VDC power sources.  But when I place them on my schematic, the

board layout shows airwires connecting the PWR pins.  How do I tell

Eagle that these power pins are not in the same net?

 

 

Robert Scott

Real-Time Specialties

Ypsilanti, Michigan

 

  • Robert Scott schrieb:

     

    I have two instances of an op-amp that must be connected to different

    +15VDC power sources.  But when I place them on my schematic, the

    board layout shows airwires connecting the PWR pins.  How do I tell

    Eagle that these power pins are not in the same net?

     

    Those opamps have implicit power gates connecting to V+ and V- (IIRC).

    They won't connect to your +15V net if that is named +15V, BTW.

     

    Simply use INVOKE to make those power gates visible and then connect the

    power pins to whatever nets you like. Approve the ERC warnings you get.

     

    Tilmann

     

  • On Mon, 02 Mar 2009 18:11:01 +0100, Tilmann Reh <user@domain.invalid>

    wrote:

     

    Robert Scott schrieb:

     

    I have two instances of an op-amp that must be connected to different

    +15VDC power sources.  But when I place them on my schematic, the

    board layout shows airwires connecting the PWR pins.  How do I tell

    Eagle that these power pins are not in the same net?

     

    Those opamps have implicit power gates connecting to V+ and V- (IIRC).

    They won't connect to your +15V net if that is named +15V, BTW.

     

    Simply use INVOKE to make those power gates visible and then connect the

    power pins to whatever nets you like. Approve the ERC warnings you get.

     

     

    This particular op-amp does not have separate power gates.  If I try

    to use INVOKE on it I get a message box saying "Part only has one

    gate."  This op-amp is a single, and the power pins are already

    visible on the schematic, but at present they are not connected to

    anything.  But the airwires are still there in the board.

     

    Robert Scott

    Real-Time Specialties

    Ypsilanti, Michigan

     

  • So, here is what I did.  Since the op-amp was already in a custom

    library of mine, I editing the library and changed the direction of

    the power pins from "PWR" to "PAS".  No more complaints.  Of course it

    is now up to me to ensure that the power pins get connected to

    something, because ERC is not going to warn me about it any more.

     

     

     

     

    Robert Scott

    Real-Time Specialties

    Ypsilanti, Michigan

     

  • Robert Scott wrote:

    So, here is what I did.  Since the op-amp was already in a custom

    library of mine, I editing the library and changed the direction of

    the power pins from "PWR" to "PAS".  No more complaints.  Of course it

    is now up to me to ensure that the power pins get connected to

    something, because ERC is not going to warn me about it any more.

     

     

     

     

    Robert Scott

    Real-Time Specialties

    Ypsilanti, Michigan

    With your original version on the sch just add a net stub to the power

    pin on each instance and name it the correct net name. You could use a

    supply symbol instead but would have to make one for the +15V_a and one

    for the +15V_b supply.

     

    Paul R.