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Change implicit power supply definitions on schematic level

Question asked by evan.w on Jul 9, 2015
Latest reply on Jul 10, 2015 by robert_davies

I downloaded the ODA starter library to begin playing around with xDX Designer in PADS VX.0 and noticed that most ICs consisting of multiple gates define the power supply and ground pins implicitly (e.g., a dual op-amp package like the LM393AN has the supply voltages defined as "V+" on pin 8 and "V-" on pin 4, or on a 74xx quad logic gate, Vcc and GND on their respective pins.) See below, for example:

PropertiesDialog.PNG

The bottom two properties designate pin 4 and 8 as the negative and positive supply voltages, respectively. However, if I change the property value to match the name of my net for one of the nets (e.g., if I change "V-;4" to "-10V,4") then the property field for the other signal pin disappears. I am then unable to add another "Signal" property field as that is not one of the options that pops up when adding a new field. See below:

This leads me to believe that this is either a bug with the part library and/or DXDesigner, or that this is not the proper way to change the signal pin definition (and I am leaning towards the latter.) It may be that it is simply not best-practice in circuit design to have circuits that have different supply voltages for op-amps or other ICs, however this is the case for several of our legacy designs where we have some op-amps getting +/-15V and others getting +/-10V for example, and the particular design and components necessitate it.

 

Without editing the library part, is there a way to manually select the net that the signal pins connect to for individual symbols in a schematic/block? (See above for example, where one instance of an op-amp must have V+ and V- mapped to +/- 10V respectively, and the other to +/- 15V)

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