U310 JFET???
0000-Admin(0000)
U310 n-channel jfet. I've looked through my DigiKey and Mouser catalogs,
along with catalogs from smaller suppliers, without finding it. Can anyone
point me to a source for this device? Is this really a valid part number?
--
Michael Bendio WT7J m...@titan.wordperfect.com 801 222-5367
Opinions are my own and aren't necessarily shared by Wordperfect Corporation
Ian D. Gay
>I'm gathering the parts for a 2-meter vfo. One of the transistors is a
>U310 n-channel jfet. I've looked through my DigiKey and Mouser catalogs,
>along with catalogs from smaller suppliers, without finding it. Can anyone
>point me to a source for this device? Is this really a valid part number?
It's a Siliconix part. I think J310 is the same thing in a plastic
package, if you don't need the metal can.
Alan Bloom
: In article <gay.75...@sfu.ca> g...@selkirk.sfu.ca (Ian D. Gay) writes:
: >mb@xmb (0000-Admin(0000)) writes:
: >
: >>I'm gathering the parts for a 2-meter vfo. One of the transistors is a
: >>U310 n-channel jfet.
: >It's a Siliconix part. I think J310 is the same thing in a plastic
Correct
: Is it my imagination, or is the noise on the plastic packages much higher
: than the metal can equivalents?
I think it's your imagination. I can imagine that the plastic case could
possibly cause increased 1/f noise (low-frequency) due to surface
contamination, but at VHF frequencies, the performance should be the same.
AL N1AL
David Josephson
>In article <CJ2MA...@srgenprp.sr.hp.com> al...@sr.hp.com (Alan Bloom) writes:
>I wrote:
>>:
>>: Is it my imagination, or is the noise on the plastic packages much higher
>>: than the metal can equivalents?
>>
>>I think it's your imagination. I can imagine that the plastic case could
>>possibly cause increased 1/f noise (low-frequency) due to surface
>>contamination, but at VHF frequencies, the performance should be the same.
>Sorry, I'm an audio fellow and used to a regime where the 1/f noise is
>dominant. Anything over 30 MHz is complete voodoo.
>I did get a reply in mail, however, from a fellow who was unable to
>post, and I include it here for general edification:
[stuff deleted, said it was mostly the same]
It's not your imagination, *if* you're running at high input impedances
(like I do, making condenser mic innards, input Z > 1.5 G ohms). In most
cases, the American black plastic used for injection molding these cases
is rather leaky. A few tens or hundreds of megohms, but of course that's
way too much leakage current (ideal = 0, or less). Some of the Japanese
makers have it right and have a black plastic that's opaque enough to
prevent photons from reaching the junction but with enough insulation
between the particles of pigment that no current flows. Some nuclear
instrumentation types use metal can fets and saw off the can so they can
clean the surface of the die, reporting significant improvement from this
process.
--
David Josephson <da...@josephson.com>
The Half Elf
: mb@xmb (0000-Admin(0000)) writes:
: >I'm gathering the parts for a 2-meter vfo. One of the transistors is a
: >U310 n-channel jfet. I've looked through my DigiKey and Mouser catalogs,
: It's a Siliconix part. I think J310 is the same thing in a plastic
: package, if you don't need the metal can.
You can find also this part in the "Motorola small-signal transistor handbook"
I can post the principal parameters if you like.
Vince.
Masahiro KITAGAWA
WT7J> U310 n-channel jfet.
WT7J> source for this device?
I am not sure about current availability of Siliconix U310 (canned).
But you can probably use J310 (plastic-molded) as well, which you can
find easily. See ads of RF PARTS in QST for example. Also Sony's
2SK125 can be used in place of J310.
masa
*--- **** ***-- *--* *-* *-* QRZ? de JH3PRR
Masahiro Kitagawa <kita...@ee.es.osaka-u.ac.jp>
--
Masahiro Kitagawa <kita...@ee.es.osaka-u.ac.jp> 北川 勝浩
Electric Eng., Engineering Science, Osaka Univ. 阪大・基礎工・電気
Rick Spanbauer
: I'm gathering the parts for a 2-meter vfo. One of the transistors is a
: U310 n-channel jfet. I've looked through my DigiKey and Mouser catalogs,
: along with catalogs from smaller suppliers, without finding it. Can anyone
: point me to a source for this device? Is this really a valid part number?
Active Electronics (800)-363-7601 carries the U310. I bought a few
of these recently at the local Active branch.
Rick Spanbauer, WB2CFV
SUNY/Stony Brook
Masahiro KITAGAWA
Scott> Is it my imagination, or is the noise on the plastic packages
Scott> much higher than the metal can equivalents?
The same chips are used for U310 and J310.
Input capacitances which may change NF matching condition are same
(according to the data sheets).
If someone had experienced much worse NF for J310 than for U310, the
pin connections might have been the problem:-) Their pin connections
are a little confusing.
U310 J310 2SK125
3 ----- -----
2 1 2 3 1 2 3
1 \
\/
(BOTTOM VIEWS)
1 S 1 D 1 S
2 D 2 S 2 G
3 G & case 3 G 3 D
Be careful!
Bob Hale
The same die in the can will probably have a lower noise figure than
the plastic version of that device becuase the metal can provides
a better thermal path and therefore a lower die temperature.
Bob Hale ...!ucsd!btree!hale
...!ha...@brooktree.com (preferred)
Masahiro KITAGAWA
DJ> It's not your imagination, *if* you're running at high input
DJ> impedances (like I do, making condenser mic innards, input Z >
DJ> 1.5 G ohms).
This is far from the situation in which U310/J310s are used for low
noise *RF* frontend. Optimum NF matching to 50 ohm input line is much
easier for grounded gate configuration because it offers nearly
optimum input impedance (~100 ohm) without matching circuit.
Broadband NF matching can be achieved by just paralleling a pair of
JFETs.
Sehne
I recently completed building a QST 20m QRP receiver project which involved
winding my own toroids, from pre-written instructions. (3 turns on form # XX-T-)
I've become fascinated with them & would like to learn how to "roll my own"
Where can I buy a small sample of toroids & where can I learn how to design with
them? (Application info)I've had trouble locating them in catalogs like DigiKey.
Can someone post some info or e-mail directly? Thanks
Gary (N2KTY/QRP)
Drew Diamond
>From: seh...@austin.ibm.com (Sehne)
>Subject: Toroid info
>Date: Thu, 6 Jan 1994 23:28:55 GMT
Gary,
Write to Amidon Associates, 12033 Otsego Street, N. Hollywood Ca. 91607;
they can supply a comprehensive data sheet/application notes/design
formulae for their toroidal, E and pot-cored products. My copy was free
with my last order.
73 Drew, VK3XU. Telecom Australia Research Laboratories.
Galen Watts
>In article <CJ8EK...@hawnews.watson.ibm.com> seh...@austin.ibm.com (Sehne) writes:
>>I've become fascinated with them & would like to learn how to "roll my own"
>>Where can I buy a small sample of toroids & where can I learn how to design with
>Write to Amidon Associates, 12033 Otsego Street, N. Hollywood Ca. 91607;
>they can supply a comprehensive data sheet/application notes/design
>formulae for their toroidal, E and pot-cored products. My copy was free
>with my last order.
>73 Drew, VK3XU. Telecom Australia Research Laboratories.
Also try Fair-Rite Products, Box J, Wallkill, NY 12589, 914-895-2055
and Palomar Engineers, Box 462222, Escondido,CA 92046, 619-747-3343.
I use Amidons, but they're available at my local electronics shop.
Also get/checkout a copy of the ARRL handbook. Chapter 2 has much info on
ferrites.
Galen, KF0YJ
Randy
:
: Where can I buy a small sample of toroids & where can I learn how to design with
: them? (Application info)I've had trouble locating them in catalogs like DigiKey.
:
: Can someone post some info or e-mail directly? Thanks
:
: Gary (N2KTY/QRP)
Also try Polomar Engineers phone 619-747-3343 (Calif)
get their free cat...ALL the info is IN the cat!
--
Randy KA1UNW If you get a shock while
servicing your equipment, "Works for me!"
ra...@192.153.4.200 DON'T JUMP! -Pete Keyes
You might break an expensive tube!