multisim

[NavidG]

Now it works, thanks, but one more thing: in my schematic model for PA96, I don't see other pin numbers for upper two pins. How I can see them on the schematic ( pin 2 and 7 are not labled)?

Thanks

Navid

[jcham]

The footprint numbers you see are for the footprint that will be used by the component when transferring to board layout (Ultiboard). The reason you don't see numbers for the upper two pins is that no symbol-to-footprint mappings have been made for those two pins (BAL1 and BAL2). 

If you double-click the component and click Edit footprint, you can see that no footprint pins have been assigned to symbol pins BAL1 and BAL2. From this dialog you can assign pins 2 and 7 if you wish. 

Hope that helps.

Jeff

National Instruments

[NavidG]

It seems I can't make proper pin mapping as the op amp sim results are garbage. I attached the design file here. My issue is with pins 2, 7, and 8. 

Also, when I change u1, u2 doesn't change, but my assumption was u2 is just a copy of u1.

Thanks

Navid

[NavidG]

just to add: I am simulating u1 in unity gain buffer configuration and using Cc and RL as PA96 data sheet.

[jcham]

Hi Navid,

When you edit the footprint or model of a component placed on the schematic, your changes will only affect that instance of the component, even if there are other instances of the same component on the schematic and even if they were copied from one another. 

If you want to make "permanent" changes to the component stored in your database, you can open the component properties and click "Edit component in DB". Any changes you make there will be saved in your database and will be reflected in any instances of the component you place in the future. To update instances of the component already placed on the schematic after making changes in the database, you can use the Update Components tool, founder under Tools>Update components...

Regarding the pin mapping: the numbers you see next to the pins on U1 and U2 are used for footprint pin mappings only - they are unrelated to simulation. If you plan on transferring your design to Ultiboard for PCB layout, they should be properly mapped, but otherwise they do not affect simulation results. 

Jeff

National Instruments

[NavidG]

Hi Jeff,

Thanks for your all useful reposnses so far. I don't know how I can connect pins for my simulation for this Apex op amp. In other words, I can't find out where each pin on the schematic map to netlist. My simulation results are garbage and I tried editing the DB in multisim using spice pin numbers, but not succesfull.

I have attached a unity feedback config for u1 here with Cc between pin 7 and 8 and RL beween 1 and 2. Please help.

Thanks
Navid

[jcham]

The circuit topology is completely up to you and what you are trying to implement. You look to be on the right track witht Cc and RL on U1, but if you are trying to follow the typical application circuit (the one from the PA96 datasheet), you probably want to wire V2 to the negative opamp terminal and add a feedback resistor, while connecting the positive input to ground. 

If you are confused about which symbol pins map to which nodes in the SPICE model, you can view the symbol-to-model pin mapping table when editing the component in the database. Click the Edit in database... button and go to the model tab, from there you can see (and change) the mappings. 

For example, in the SPICE model pins 1 and 2 map to the OUT and CL pins, respectively. In the mapping table you can see that pin 1 maps to symbol pin "OUT" and pin 2 maps to symbol pin "COMP". If you wanted your symbol to match the datasheet more closely you could rename symbol pin "COMP" to "CL" on the Symbol tab. 

[NavidG]

I had done all of DB editing you said before but the sim results are gabag. I used same topology for 741 op-amp, and it was fine for 741. I also tried same circuit as PA96 data sheet and similar garbage results I get ( output saturates for small signal input I give). Most probably I am connecting the pins incorreclty. I need help.

[NavidG]

Maybe if you can provide me with the PA96 library file for Multisim my issue will be gone.

[jcham]

Unfortuntely the PA96 is not part of our master database; there is no library file for Multisim we can distrubute. However I've created a custom component from the public model and attached it here. 

To open it, simply drag the file onto your schematic. From there you can save the placed part to your corporate or user database if you wish. 

Please not although the symbol and model mapping are correct, the component has no footprint information. It can be used for simulation, but if you want to transfer it to Ultiboard you will have to add a footprint.

Jeff

National Instruments