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Enno

02/11/2023, 6:28 PM
it might be a beginner question, but on the 1V8 nfet and pfet, what do these paramters actually mean in the design? L and W are self explaining, but what are mult and nf?
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Roberto Di Lorenzo

02/11/2023, 8:13 PM
Mult is the multiplicity factor, if you put m=2 it means that you have two transistor in parallel. Nf is the number of finger for the transistor. Let's wait more technical details from the expert of the forum 😀
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Stefan Schippers

02/11/2023, 11:23 PM
@Roberto Di Lorenzo is right,
``mult``
is the number of parallel devices. If you use
``m=10000``
you are simulating 10000 parallel devices but the simulation cost is just 1 mos device. The simulator multiplies all needed parameters (current, capacitances, etc) by 10000.
``nf``
defines the number of gate fingers. Given W=10 and L=1 you can draw this transistor on the layout in different ways. below the same transistor drawn with nf=1 and nf=2 fingers. The first one has xschem parameters
``W=10 L=1 nf=1``
, the second has parameters
``W=10 L=1 nf=2``
. In xschem W is always the total width. In the second case the actual layout has 2 gate fingers each one has width 5 so 5*2=10 is the total W.
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