If you want to get data about a certain transistor you should always have a look also at the datasheets of other manufacturers:

http://www.datasheetcatalog.com/datasheet...C807.shtml

The label "PNP silicon AF transistor" is shit. It's an example for what happens when idiots (yes, there are also engineers being terrible idiots!) try to simplify an original datasheet!

The BC807 is the SMD-version of BC327. This transistor is a general purpose, small signal transistor, which differs refering to BC556 in that it allows remarkably high collector currents and shows very low collector emitter saturation voltage. But, like the BC556 it's not a part being suited for plain HF applications, like radio and TV tuners and such stuff, because junction capacitances (especially the feedback capacitance!) are rather high and gain bandwidth product is rather low.

So, for what applications such a BC807 can be used?
The very low collector emitter saturation voltage makes the BC807 idealy suited for switching applications, where very low saturation voltages are a must.
Also, due to the high collector current the BC807 is not only suited for front end signal amplification stages, but also in the following driver, buffer and even output stages, where considerably higher collector currents are flowing. But as the BC807 is not a special HF-transistor, it's only suited for rather low frequency driver stages, where the limited gain bandwidth product and by this the gain headroom still allows the design of low distortion stages.

So, the BC807 is primarily intended for use in switching stages and in driver and output stages of audio amplifiers.


Because the specified frequency (f=100MHz)is used in a testing circuit to determine the gain bandwidth product as a function of collector current. From this gain bandwidth product the transition frequency fT is derived (gain=1!). Sometimes fT is also called "gain bandwitdh product".


This figure is shit! Today, manufacturers no longer design the figures for each datasheet individually, but take a "suited" one from a pool of figures. So, the title of this figure has nothing to do with the actual curve! There's no set of curves with Vce as parameter. Only one, which seems to refer to Vce=5V. And the measuring frequency of f=2GHz is also false. f=100MHz seems to be the correct one.

Interesting to note, the original infineon datasheet from 1999, which is in the list above, is nice and correct.

Kai