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Old 27th February 2009, 09:57 AM   #1
qsa is offline qsa  Germany
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Default Need Assistance: To220 replacement for MJE720 or 2N2219a

Hello


Did somebody know replacement in TO220 case for MJE720 and 2n2219a devices.

MJE 720 is from Central Semiconductor buts its impossibile to get


2SD669a could be a good replacement but its not pin compatible,

This are High Speed devices and used in PA Power Amplifier as VBE


regards

Peter
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Old 27th February 2009, 10:38 AM   #2
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Quote:
MJE 720 is from Central Semiconductor buts its impossibile to get
Original-
http://parts.usbid.com/MJE720.html
modern-
same as BD135/137/139G (Hfe 40 1.5A 40-80V)


2n2219 (in a can)

https://www.littlediode.com/componen...ransistor.html
(10pf cob /50v/gain of 50)
This one isn't too fast either , even a 2n2222 (common) is
faster.. are these for a old amp?
OS
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Old 27th February 2009, 08:19 PM   #3
mjf is offline mjf  Austria
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hallo.
2n2219a available at reichelt.de
ca. 0,3 euro per unit
grüsse.............
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Old 27th February 2009, 09:27 PM   #4
anatech is offline anatech  Canada
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Hi Peter,
Quote:
2SD669a could be a good replacement but its not pin compatible,
Okay, so rotate the part so the leads line up.

The 2N2219 was a fast little thing, so if you can get by with a 50 mA device, a 2SC3423 would work well (200 MHz). The 2SC3421 has a transition frequency of 120 MHz, compared to the 2N2219A's 300 MHz rating and the 2SD669A's rating of 140 MHz.

The 2N2219A was a very common transistor, so you should still be able to scare one up somewhere. Many students taking electronics had these in there kits for their course. I imagine there must be thousands of these in closets around the world!

-Chris
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