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Design >> Analog Design >> Ouestion in symbolism...
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Message started by Turin on Mar 4^th, 2010, 6:58am

Title: Ouestion in symbolism...
Post by Turin on Mar 4^th, 2010, 6:58am

Simple question...Do the mosfet symbols in the image have the same meaning regarding where the substrate is connected?

Thanks!

Title: Re: Ouestion in symbolism...
Post by pancho_hideboo on Mar 4^th, 2010, 7:06am

It depends on a definition of MOSFET as three terminal model in model file.
See your model file.

But I think body is assumed to be connected to "source" in three terminal model of PMOS generally.

Title: Re: Ouestion in symbolism...
Post by Turin on Mar 4^th, 2010, 9:53am

There is no model file...This(1rst) is an image from a book which i'm was wondering if is means it is actually connected to the source as it generally the case...

Title: Re: Ouestion in symbolism...
Post by aaron_do on Mar 4^th, 2010, 5:33pm

The one on the left doesn't have the substrate connected yet...

Title: Re: Ouestion in symbolism...
Post by kumar on Mar 5^th, 2010, 12:29am

If substrate connection is not shown, then it implicitly means that it is connected to source. In your case both the ckts are different

Title: Re: Ouestion in symbolism...
Post by Turin on Mar 7^th, 2010, 5:52pm

So having a schematic with the first symbolism(with the body pin unconnected) for the pmos and for the nmos where do you assume that the body pin is connected in both cases.