Topband: Any experience with 2N3553?

[N2TK, Tony]

Hi Lee,
Gee, you think they are using the same 16 x 20 mil die for both parts? :-)
Both parts will be around for a very long time. They just might be expensive. The space folks like them because you can get radiation hardened parts. And following MIL-PRF-19500 specs parts are very close in performance from lot to lot. You can get them in TO-39 cans rated at 1W or UB surface mount packages rated at .5W. Or you can get die and enjoy mounting them. There is no plastic encapsulated transistors for mil and space transistors.

By the way in regards to JFETS it depends on which wafer fab they are made in regards to quality and performance from part to part. One company on the west coast that shut down several years ago had two wafer fabs - one in CA and one in AS.  The CA fab made the mil wafers and the one in AS made the commercial wafers.  The mil wafers were fairly consistent in performance  from wafer to wafer. Not so for the commercial wafers. There still is significant stock of wafers after all of these years to build "new" JFETS, both commercial and mil.

The switch from TO-cans to surface mount continues to grow. For one, the price of the TO-headers is going up at a fast rate. Some packages are no longer available such as the TO-59. And pick and place is easier with the surface mount components.

Oh, and all of these real cheap Fairchild wafers are just about all gone. Folks are scrambling for replacement of the 10 -30 cent die.

73,
N2TK, Tony


-----Original Message-----
From: Lee STRAHAN [mailto:k7tjr at msn.com] 
Sent: Sunday, July 01, 2018 8:40 PM
To: N2TK, Tony <tony.kaz at verizon.net>; martin at ok1rr.com; topband at contesting.com
Subject: RE: Topband: Any experience with 2N3553?

Thanks Tony,
   Agreed the 2N5109 will be around for a long time however as you point out they are or will be very expensive. At present I use 100's of 2N3866 transistors which are very close to the same die if not selected from the 2N5109 process. My cost in 100 quantity has gone from about $1.60 each to currently $4.00 each in about 2 years' time for 2N3866's. The 5109 is currently priced less at $2.22  where the 3866 used to be less. >From all this I conclude that the 2N5109 will follow the huge price increases. I could be wrong but I will not plan on using the 5109 especially where most things are going to surface mount also. Even J-310 FETs have gone from <$.20 to $2.41 at 100 level. Worst thing is 20% of the off brand j-310s don’t meet spec. The only way to solve this is to go to surface mount where you can still get the good J-310 and other great devices. One can often use more than one SMD device in an amplifier having it cost less than one expensive leaded  device. For the hams building a single amplifier the 5109 makes a lot of sense right now. Semiconductor times are changing rapidly. I make lots of top-band antenna systems using lots of already expensive electronics. For this reason I have to do as well as I can to predict the future for my products. My observation is that leaded parts are disappearing rapidly and this will continue.

Lee    K7TJR
Hi-Z Antennas

-----Original Message-----
From: N2TK, Tony <tony.kaz at verizon.net> 
Sent: Sunday, July 1, 2018 2:03 PM

To: 'Lee STRAHAN' <k7tjr at msn.com>; martin at ok1rr.com; topband at contesting.com
Subject: RE: Topband: Any experience with 2N3553?

The 2N5109 will be around for many years. It is widely used in the military and space community.  It is listed as a JAN part. But it ain't cheap.
73,
N2TK, Tony

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Lee STRAHAN
Sent: Sunday, July 01, 2018 2:15 PM
To: martin at ok1rr.com; topband at contesting.com
Subject: Re: Topband: Any experience with 2N3553?

Hello Martin and all,
    The 2N3553 device was plagued with a low Ft (high at its introduction)  making it mostly a low frequency device with questionable high gain high frequency use in typical ham preamps. It is no longer available through the original manufacturers. Also perhaps you are thinking of the BFQ18A and not the BFQ19A device. The BFQ19 is at end of its life cycle and in addition the 18A is widely used now in the MATV industry for wideband amplifiers. I have some experience with the 18A using it in a wideband Norton style amplifier where it is providing 10+dB of gain with a measured noise figure of 2 dB on 160 meters. Its typical IMD is at least listed at UHF on the data sheet. My IMD testing setup is not adequate to test the range of this device but I can say that it exceeds any other amplifiers I have built to date. I typically use the 2N3866 which unfortunately is pricing itself out of the market now. I suspect the 2N5109 will follow as inventories shrink.. A pair of the 18A devices at ~$1.00 USD each single price in a push pull Norton configuration would in my opinion make it worth trying as a killer wideband amp. 
Just my $.02 USD.
Lee   K7TJR  OR

-----Original Message-----
From: Topband <topband-bounces at contesting.com> On Behalf Of Martin Kratoska
Sent: Sunday, July 1, 2018 9:51 AM
To: topband at contesting.com
Subject: Topband: Any experience with 2N3553?

The 2N3553 is a brutal 7 watt device in a TO-39 metal package. Chris Trask, N7ZMY mentioned some unparalleled IM characterics

'... The BFQ19 (made by NXP née Philips) and the NE46134 (made by NEC) are both highly popular within the CATV industry, and are virtually identical in terms of linearity. They compare favorably to the 2N5109 in terms of linearity, though they pale in camparison with the 2N3553 (as do all the others)...'.

See
http://www.home.earthlink.net/~christrask/Bipolar%20Transistor%20Evaluation.pdf

2N3553 is often mentioned in transmitting applications but I was unable to find some other details like IM, noise and gain characteristics in high DR preamps for receiving purposes. Any experience?

73,
Martin, OK1RR
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