Hi Guys,

Every foundry I asked about the timing model of a saturated bjt transistor,  none has a good answer. Some model parameters they gave such as Tr, Qd, Xtr.. are not really working. It is hard to model sat of a bjt. People design with estimation and tweak circuits to get it right. Two parameters for characterizations I think are important:

1. Onset of sat, at what Vcb, the bjt starts to see charge storage?

2. What is the temp coef of the minority discharge time?

Anyone has experience with this and has more efficient method to model sat? Thanks

BJT_Sat