EMRFD Message Archive 11118

Message Date From Subject
11118 2015-06-04 14:01:02 Christer Renströ... SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
TI and OnSemi has monolithic schottky diode quads but have never used them. Skyworks Inc. has them as well, of which I have some experience using the SMS3931-021, although not in a pure mixer application.

73 de SM2UJW/ Chris 



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-------- Originalmeddelande --------
Från: "David Snowd
11119 2015-06-04 15:49:00 kb1gmx Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
There are transistor quads out there too making gilbert cells with matched devices practical.

Try the MPQ2222, that a quad 2n2222, that would make a fine high current cell.

Allison
11122 2015-06-05 04:44:09 Will Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
From the data sheet it appears the MPQ2222 is four individual die
mounted together on one substrate rather than one die with 4 transistors
on it.

The 4 individual transistors would probably be well matched but not as
well as if made on the same die. Also the lead lengths are probably
shorter with 4 separate die.

Cheers,
Will

11129 2015-06-06 08:44:53 kb1gmx Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
the older parts I have (pre on semi) are one die.


Allison
11133 2015-06-06 13:21:20 iq_rx Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
I seldom speak with absolute authority, but on this minor topic I must admit I can.  Two parts may have the same part number, data sheet and application notes, but look very different on the X-ray view.

Even so, I was still surprised when a new batch of 2N3904s turned out to be modestly good UHF amplifiers and oscillators.

Circuitry and construction practices from ancient times when transistors were slow and you had to pay extra for RF devices may no longer work with quick new devices with familiar old part numbers.

Rick
11134 2015-06-06 13:44:50 Dana Myers Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
11135 2015-06-06 14:24:37 iq_rx Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
There would be no point in that.  There is an enduring point in performing experiments with any new batch of parts you encounter, which is a theme of this site and EMRFD.  I encourage my design students to explore the capabilities of components and ICs at the bench, and then design using what they've discovered, rather than limiting themselves to existing data sheets, functional schematics, application notes, and legacy circuits.

Rick
11136 2015-06-06 14:45:28 Dana Myers Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer
11137 2015-06-06 15:42:21 Dana Myers Re: SV: Re: [emrfd] Discrete component version of Gilbert Cell Mixer