MJE340 MJE350 detalied data, more than the datasheet

peranders · 15th November 2002, 09:03 AM

MJE340/350, does anybody have more data about these? I have looked at Thomson and ON. They say nothing about fT, caps or other frequency properties.

The current gain is >30, typ 240. Does anybody know what the real life value is (in average)?

I'm thinking of testing these transistors in my QRV-02 headphone amp. Now I use BD139, 140, good old work horses.

Christer · 15th November 2002, 09:58 AM

You haven't considered the newer Toshiba drivers 2SA1837 and 2SC4793? They have a typ. fT of 100MHz and are available from Elfa, although a bit more expensive than the MJEs. See http://www.elfa.se/elfa/produkter/se/20/2022252.htm

I have considered using these instead of 2SB649/2SD669 which
are now discontinued from Elfa (not from the manufacturer, though).

halojoy · 15th November 2002, 10:19 AM

Is SOT186 an insulated case?

Christer · 15th November 2002, 10:27 AM

Quote:

Originally posted by halojoy
Is SOT186 an insulated case?

The datasheets don't say anythinhg about that. However, I
found this on the net http://www-us9.semiconductors.com/cg...package/SOT186 so assuming that Toshiba and Philips
agree on what SOT186 is, then it is insulated.

peranders · 15th November 2002, 10:44 AM

Quote:

Originally posted by Christer
You haven't considered the newer Toshiba drivers 2SA1837 and 2SC4793? They have a typ. fT of 100MHz and are available from Elfa, although a bit more expensive than the MJEs. See http://www.elfa.se/elfa/produkter/se/20/2022252.htm

I have considered using these instead of 2SB649/2SD669 which
are now discontinued from Elfa (not from the manufacturer, though).

My interest was only "do they work". I have those and they are like replacements for BF471/472, high power amp drivers.

The last question: No, my goal is to use easy-to-get-parts, in Sweden Elfa. But since the output stage aren't very special, there are lots of room for experiment.

Elso Kwak · 15th November 2002, 10:46 AM

Quote:

Originally posted by peranders
MJE340/350, does anybody have more data about these? I have looked at Thomson and ON. They say nothing about fT, caps or other frequency properties.

The current gain is >30, typ 240. Does anybody know what the real life value is (in average)?

I'm thinking of testing these transistors in my QRV-02 headphone amp. Now I use BD139, 140, good old work horses.

peranders,
As they don't give Ft it is probably < 3MHz i.e. slow or general purpose transistor.

peranders · 15th November 2002, 11:06 AM

Quote:

Originally posted by Elso Kwak

peranders,
As they don't give Ft it is probably < 3MHz i.e. slow or general purpose transistor.

Yes (but I'm not sure, haven't tested), but it's rather unusual not to give the fT at least.

PH104 · 16th November 2002, 12:19 PM

Peranders

I replied to you in more detail in AudioAsylum. Yes, they will work.

P.Lacombe · 16th November 2002, 04:00 PM

Peranders,

I have measured Ft for this transistors some years ago.

Results were 20 to 30 Mhz for MJE340, but 8 to 12 for MJE350.
They work very well as drivers for Mosfets, but only as "up" transistor in cascode configuration. Or as constant-current source or sink.

Regards, Pierre Lacombe.

peranders · 16th November 2002, 05:47 PM

Thank you for the measurements.

15th November 2002, 09:03 AM	#1
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	MJE340 MJE350 detalied data, more than the datasheet MJE340/350, does anybody have more data about these? I have looked at Thomson and ON. They say nothing about fT, caps or other frequency properties. The current gain is >30, typ 240. Does anybody know what the real life value is (in average)? I'm thinking of testing these transistors in my QRV-02 headphone amp. Now I use BD139, 140, good old work horses. __________________ /Per-Anders (my first name) or P-A as my friends call me

15th November 2002, 10:19 AM	#3
halojoy On Hiatus Join Date: Nov 2002	SOT186 Is SOT186 an insulated case?

16th November 2002, 05:47 PM	#10
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Thank you for the measurements. __________________ /Per-Anders (my first name) or P-A as my friends call me

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15th November 2002, 09:58 AM	#2
Christer diyAudio Member Join Date: Sep 2002 Location: Sweden	You haven't considered the newer Toshiba drivers 2SA1837 and 2SC4793? They have a typ. fT of 100MHz and are available from Elfa, although a bit more expensive than the MJEs. See http://www.elfa.se/elfa/produkter/se/20/2022252.htm I have considered using these instead of 2SB649/2SD669 which are now discontinued from Elfa (not from the manufacturer, though).

16th November 2002, 12:19 PM	#8
PH104 diyAudio Member Join Date: Nov 2001 Location: New Mexico	Peranders I replied to you in more detail in AudioAsylum. Yes, they will work.

16th November 2002, 04:00 PM	#9
P.Lacombe diyAudio Member Join Date: Jul 2001 Location: Orleans, France	Peranders, I have measured Ft for this transistors some years ago. Results were 20 to 30 Mhz for MJE340, but 8 to 12 for MJE350. They work very well as drivers for Mosfets, but only as "up" transistor in cascode configuration. Or as constant-current source or sink. Regards, Pierre Lacombe.

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