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ad8397 simulation problem

post #1 of 3
4/9/10 at 1:05pm
Thread Starter 
I have download a spice model of ad8397 from AD website

but neither of my spice software including ltspice and multisim can run simulation with this spice model

but I can run ad633's model on both software

according to the error info,I took a look inside the spice file,i found that ad8397 only define 5pins instead of 8pins model and two of them are defined as pin90 and pin55,I modified my simulation to a 5pin conponent but i still fail at last

both of the simulation soft are warning that,the instance(which stands for the component symbol i used to sim)have more pins than the spice model,but i have check lots of times to make sure i am truely using a 5 pin instance....

who can tell me why and how to solve ?

i want to simulate my design of ad8397
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post #2 of 3
4/9/10 at 7:20pm
the Ltspice Yahoo group is a source of info on Ltspice usage, join and search for explainations and example files

but a basic spice book is a good idea too - LTspice and the users group assume basic spice operation knowledge

in a symbol the pins are numbered 1 to n, matched to the 1st n args of the subcircuit model file
the subcircut declaration args in your netlist are your crcuit's node#, mapped to the symbol pin # by position, you shouldn't need to know the subcircuit internal node names

an example of using the standard Ltspice "opamp2" symbol with a 3rd party op amp subcircuit: (either of post #2,3 )

High loop Gain Composite Op Amp Circuits - diyAudio (attachment is LtSpice .asc file, just download, edit filename to remove .txt extension and it should run in LtSpice)

searching for posts with photobucket, .asc, Ltspice keywords by jcx on diyAudio would be a way to find a few working LtSpice sims of audio related circuits, a few with op amps
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post #3 of 3
4/10/10 at 12:45am
Thread Starter 
finally i solve this problem.
i've made a mistake of the mechanism of spice model
the key is :
"the symbol model must fit the spice netlist model"

in detail,i just modified a asy file.
1.cut the model into a 5 pins model ,as to say,del the no.6-no.8 pin's lines and save it as a new file,let's name it newsym.asy
2.creat a new draft and pick the newsym in your draft
3.right click and fill the "spicemodel" blank with your spice model name,for example here is "ad8397"
4.copy the cir file e.g. ad8397.cir downloaded from ADI to the /lib/sub
5.press s and add a line:.include ad8397.cir

then,with peripheral conponents,you can run the simulation to test your design

this method can deal with any other cir spice model you found in any manufacturers.

i hope this will be a new powerful and trustful tools for you all when designing audio circuit.

p.s.:ADI aslo provides a ADI edition of multisim for free for any designer,it is very useful except that some new chips' model are not included in the library and we can not "hack" it as i do in ltspice,but it is still a very good choice to help you simulate your design and analyse performance
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