sinusoidal amplifier 1 MHz

[David Hess]

A composite amplifier with good performance at 1 MHz and higher would be an interested design project that I will have to try some day.  Unfortunately most of high performance transistors which would have been used in the past for this sort of design are no longer available.

Rohm has some interesting transistors, like the 2SAR/SCR574/586.

Those look like ring/perforated emitter transistors because of their flat hfe versus frequency.

There are lots of options up to maybe 10 MHz, but 1 GHz NPN/PNP complementary power transistors used to be available.