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Re: AKO: Fails When Placed in Sub-Schematic

 

Hello All:
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Answering eT's question:
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On the top level, writing ".model LoBT5551 ako:MMBT5551 NPN (Bf=80)" with the NPN,
as well as, writing ".model LoBT5551 ako:MMBT5551 (Bf=80)" without the NPN, produces in both cases;
".model lobt5551 npn (... bf=110 ...) (bf=80)" in the expanded netlist.
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In a .subckt, writing ".model LoBT5551 ako:MMBT5551 NPN (Bf=80)" with the NPN produces;
".model x10:lobt5551 npn (... bf=110 ...) (bf=80)" in the expanded netlist.
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In a .subckt, writing ".model LoBT5551 ako:MMBT5551 (Bf=80)" without the NPN produces;
"Can't find definition of model LOBT5551".
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All for now
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Sent:?Sunday, February 09, 2025 at 12:29 AM
From:?"eetech00 via groups.io" <eetech00@...>
To:[email protected]
Subject:?Re: [LTspice] AKO: Fails When Placed in Sub-Schematic
On Sat, Feb 8, 2025 at 05:43 PM, David Schultz wrote:
On 2/8/25 7:37 PM, Andy I via groups.io wrote:
It is most curious that adding "NPN" to the statement seems to fix it,
and that "NPN" is not needed outside of subcircuits.? I'd say it is a
bit buggy.
I would be worried about what parameters you actually get when adding
NPN. Do you modify the Bf parameter of a a generic NPN model or of the
one in the alias?
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A model statement like this:

.model LoBT5551 ako:MMBT5551 NPN (Bf=80)
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expects a ".model MMBT5551 NPN (Bf=blah blah blah....)" to already be defined.
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It will replace the original BF value with the aliased value when LoBT5551 is used in the schematic. This can be verified by running a simulation with the expanded net list set, then viewing the error logfile. If BF is already defined, it will be listed twice in the models parameter list, with the new one at the very end of the models' original parameter list, overriding the first BF parameter setting.
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eT
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