0
\$\begingroup\$

Let's say we have vanilla BC846 (80V), BC847 (50V), BC848 (30V) transistors from the same company, each with 3 bins A, B, C where C supposed to have to highest hfe.

Is that correct, that BC846C should be the fastest, and for example BC847C or BC846B are slower (i.e. have higher capacitances and slower switch-on/off speed)?

Improve this question
\$\endgroup\$
4
\$\begingroup\$

I would think they're equally fast, since the datasheet mentions just one value for \$f_T\$, not different values per \$h_{FE}\$ class.

Improve this answer
\$\endgroup\$
  • \$\begingroup\$ Yes, that's official information. But in reality they should be different - lower max. voltage and higher hfe should mean thinner base => higher speed. \$\endgroup\$ – BarsMonster Jun 24 '11 at 10:08
  • \$\begingroup\$ @BarsMonster, Or they could be adding dopant which has a small change in leakage current and causing the channel to have a higher mobility. There is no way to just look at two transistors and know based off of voltage rating. \$\endgroup\$ – Kortuk Jun 24 '11 at 10:37
  • \$\begingroup\$ I an impression, that pins appears from the fact that parameters have some variation, and transistors are just sorted by the results of actual tests... \$\endgroup\$ – BarsMonster Jun 24 '11 at 12:29
  • \$\begingroup\$ @BarsMonster: for \$H_{FE}\$ very likely, for \$V_{CE}\$ I don't know. How would you test this non-destructively? \$\endgroup\$ – Federico Russo Jun 24 '11 at 12:38
  • \$\begingroup\$ Vce brakedown is not destructive when you do so with controlled current (i.e. 1-10ma max). \$\endgroup\$ – BarsMonster Jun 24 '11 at 12:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.