BJT Hfe Curves

[chrissoo]

Hi
Does anyone have Spice model for 2SA1186 and 2SA1860? These are great transistors from Sanken, unfortunately Sanken does not provide any model.

I would appreciate it very much if someone can direct me to reasonably accurate models.

Thanks
Chris

 

[hahfran]

hfe is a constant of a set of differential equations used in 4-pole theory. I.e. is an algebraic equation which is the solution of a differential equation under boundary conditions. It is practically useless to depict hfe in a graph as hfe in frequency domain is complex. Thus all those gain graphs refer to time domain. In practice they are taken pulsed
and are algebraically derived or normalized to constant junction temperature.
Most of these values are not sufficient if one is to compute a lead/lag compensation thus to ensure stability of an amp under various complex loads. Then you'll need the complex four pole parameters to meet Bode conditions or restrictions, resp.

 

[keantoken]

Within the low audio range I don't think it can be that bad. Worst case I see is outputs, which begin to act up upwards of 10kHz, though some of the pricier ones do wonders.

We are discussing Hfe vs. Ic, but maybe the datasheet makers are confused, and should be saying Beta vs. Ic instead. Maybe it even means different things in different countries. :/

Thanks for your input.

Crissoo, I think I might have heard of models for those on the LTSpice yahoo group, not sure. You will have to sign up though.

- keantoken