Surfce mount J310s and Replacement of U310 with J310
The U310 is becoming hard to get and when available costs close to $15. With its grounded gate to the case and two gate leads, it was easy to shield the output from the input in the manner Rick related, have short leads, and hence it was straight forward to make a stable VHF preamp.
I like Rick’s suggestion for using the J310 and will do it the next time I use it. Does anyone else have experiences using the J310 in place of the U310? I know Rick’s 2M and 6M converters use it successfully. In particular, I wonder if anyone has used the surface mount J310, which is widely available and cheap in grounded gate preamplifiers, and if so, how it worked. In some sense surface mount devices and ugly construction are sisters under the skin as everything is on one side of the board and traces can be located to take the shortest length from part to ground, part to part and input to output.
Another advantage of the J310 grounded gate preamp is that it is pretty robust to accidentally applied power to the input or output. - Duffey KK6MC
-- KK6MC James Duffey Cedar Crest NM
9470
2013-12-02 05:58:14
Chris Trask
Re: Surfce mount J310s and Replacement of U310 with J310
> >The U310 is becoming hard to get and when available costs close to $15. With its grounded gate to the case >and two gate leads, it was easy to shield the output from the input in the manner Rick related, have short >leads, and hence it was straight forward to make a stable VHF preamp. > >I like Rick’s suggestion for using the J310 and will do it the next time I use it. Does anyone else have >experiences using the J310 in place of the U310? >
Re: Surfce mount J310s and Replacement of U310 with J310
I had to laugh at the pricing page of this 2008 document linked in Chris' posting. The U-310 is listed as $0.25 and the J-310 at $0.17. I just checked digi-key. The non-stock U310 is listed as $11.05 with a minimum quantity of 200. Over the roughly 8 years, that's an inflation factor of 60% per year. I’m beginning to understand why some are choosing to collect legacy components as an investment! ($0.25 x 1.6^8=$11.05)
Others have already questioned about the use of the SOT 23-3 version readily available in Q=1 for <$1 and in quantity at <$0.11. If the performance is similar, or even better, I'll stop grieving and just move on to only consider those construction techniques that use SMT.
Ford-N0FP
-----Original Message-----
9472
2013-12-02 07:40:40
Chris Trask
Re: Surfce mount J310s and Replacement of U310 with J310
> >I had to laugh at the pricing page of this 2008 document linked in Chris' posting. The U-310 is listed as >$0.25 and the J-310 at $0.17. I just checked digi-key. The non-stock U310 is listed as $11.05 with a >minimum quantity of 200. Over the roughly 8 years, that's an inflation factor of 60% per year. I’m >beginning to understand why some are choosing to collect legacy components as an investment! >($0.25 x 1.6^8=$11.05) > >Others have already questioned about the use of the SOT 23-3 version readily available in Q=1 for <$1 and >in quantity at <$0.11. If the performance is similar, or even better, I'll stop grieving and just move on >to only consider those construction techniques that use SMT. >
Prices for thru-hole parts have gone up exponentially since that was written. I've amassed a collection of a number of thru-hole semiconductors, including HCMOS and linear ICs, for experimentation bench stock. There's a bit of a market for SOIC to DIP adapters out there.
Re: Surfce mount J310s and Replacement of U310 with J310
Ford,
Nothing prevents anybody from using a hybrid construction method that uses both through-hole and SMT devices ... nor combining that with Manhattan and dead-bug style.
I've even constructed projects in which I soldered SMT components directly on the pins of DIP ICs, and then socket-mounted the ICs.
And occasionally I still build with miniature receiving tubes. This is a hobby, and experimentation is good. Tinkering is better.
73
Jim N6OTQ
9474
2013-12-02 08:48:00
Dana Myers
Re: Surfce mount J310s and Replacement of U310 with J310
9475
2013-12-02 09:17:11
Dana Myers
Re: Surfce mount J310s and Replacement of U310 with J310
9476
2013-12-02 10:07:34
Dana Myers
Re: Surfce mount J310s and Replacement of U310 with J310
9478
2013-12-02 11:33:06
Chris Trask
Re: Surfce mount J310s and Replacement of U310 with J310
>
9479
2013-12-02 12:16:29
Graham / KE9H
Re: Surfce mount J310s and Replacement of U310 with J310
What are some of the manufacturers/part-numbers for the SMT version of the dual gate MOSFETS/ --- Graham / KE9H
==
9480
2013-12-02 12:40:10
Ed Manuel
Re: Surfce mount J310s and Replacement of U310 with J310
Wes, W7ZOI was using BF998 DG Fets in a suface mount preamp for 50 mhz - breadboard construction.
See Mouser Part #: 771-BF998-T/R. Made by NXP and Infineon. Current price 38 cents in single's.
Ed, N5EM
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9481
2013-12-02 12:53:51
Lasse Moell
Re: Surfce mount J310s and Replacement of U310 with J310
NXP has a good range, and inexpensive too http://www.nxp.com/products/rf/transistors/mosfet/mosfets/n_channel_dual_gate_mosfets/#products
AFAIK all are SMT
/Lasse SM5GLC
2 december 2013, Graham / KE9H skrev:
What are some of the manufacturers/part-numbers for the SMT version of the dual gate MOSFETS/ --- Graham / KE9H