Fast transistors?

[janneman]

Hi,

I'm looking for complementary transistors, small signal (say ~1W Pc), Vce min 120V. They MUST have very low capacitance / very wide bandwidth. I'm trying to push a Vas stage to 20MHz open loop. I'm looking at less than 10pF Ccb...

Any ideas?

Jan Didden

[Jan Dupont]

2SA1540/2SC3955 would have been suitable if it was not for the 1W Pc and the fact that they are very hard to get as Sanyo brand

But look towards video applications......

[roender]

2sa1360/2sc3423
ft 200Mhz at 5mA Ic !!!
2.5pF Cob

[jacco vermeulen]

Originally posted by roender
2sa1360/2sc3423

aka 2SA1145/2SC2705 with a heatsink.

[lineup]

Originally posted by janneman
Hi, I'm looking for

- complementary transistors,
- small signal (say ~1W Pc),
- Vce min 120V. They MUST have very
- low capacitance / very wide bandwidth.

I'm trying to push a Vas stage to 20MHz open loop. I'm looking at less than 10pF Ccb...

This is not easy, I would say.
You could find higher voltage fast transistors. Suitable.
But the hook may be Complementary NPN-PNP.
This would reduce your options the most.

Of course there are not so many fast at 1 Watt (as it is at 0.5 Watt).
I would look for VIDEO Transistors.
They usually can take higher volts and they are fast.
But video not often come in complementary pairs.

The best VAS transistors I have seen mentioned in forum
are some complementary Panasonic devices.

[lineup]

We have had some good topics on VAS transistors.
With good suggestions

Try this www.google.com search:

site:www.diyaudio.com vas transistors

Direct link:
Google search VAS transistors

[janneman]

Originally posted by lineup
We have had some good topics on VAS transistors.
With good suggestions

Try this www.google.com search:

site:www.diyaudio.com vas transistors

Direct link:
Google search VAS transistors

Thank you lineup, I wasn't aware that you can search this way with Google in diyaudio! I always used the internal forum search which is less than perfect...

Jan Didden

[syn08]

2SC3601/2SA1407 from Sanyo.

The best money can buy, not cheap or easy to find though. Used in the PGP amp, they have Ft=400MHz.

[janneman]

Originally posted by syn08
2SC3601/2SA1407 from Sanyo.

The best money can buy, not cheap or easy to find though. Used in the PGP amp, they have Ft=400MHz.

Yes, very good! There are others that are similar, so I guess the final selection should be price & availability.

Thanks,

Jan Didden

[jacco vermeulen]

If you like the A1407/C3601 and 120V will suffice, you are going to love the 2SA1538/C3953.
50-60 €ct, for example : Cricklewood in the UK should have them.