who knows what is the FT for TIP122,please

[ljm_ljm]

TIP122 pdf, TIP122 description, TIP122 datasheets, TIP122 view ::: ALLDATASHEET :::

thanks.

[djoffe]

On Semiconductor data sheet shows typical hfe of 60 at 500 kHz, for Ft of 30 MHz. Strangely, the worst case limit is given as 4 MHz (hfe=4 at 1 MHz).

[ljm_ljm]

thanks very much

[wahab]

Originally Posted by djoffe

On Semiconductor data sheet shows typical hfe of 60 at 500 kHz, for Ft of 30 MHz. Strangely, the worst case limit is given as 4 MHz (hfe=4 at 1 MHz).

There s nothing strange..
Since it s a darlington, frequency roll off will be 12db/octave.

Gain of 60 at 500khz, so gain of 15 at 1mhz, about 4 at 2mhz
and logically, we end at 1 at 4mhz....