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7482Re: [softrock40] PIN Diodes

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  • Dan Andersson
    Dec 3, 2006
    • 0 Attachment
      Tilman,

      Jo - Handboken har varit till stor hjälp när jag först ville börja pula med
      pin dioder.

      Kul att den finns allmänt tillgänglig på nätet.


      //Dan


      On Sunday 03 December 2006 12:57, Tilman D. Thulesius wrote:
      > Dan
      >
      > I found the "pinhandbook.pdf" on teh net here:
      >
      > www.microsemi.com/literature/pinhandbook.pdf
      >
      > Looks interesting I must say.
      >
      > / Tilman SM0JZT
      >
      > > Pin diode switches are as reliable ( more reliable! ) as manual
      > > switches if
      > > designed properly!
      > >
      > > You can use power pin diodes for bandpass switching in the PA but the pin
      > > diodes are more often used in low power applications.
      > >
      > > I tested some pin diodes in a SoftRock receiver and replaced the FST
      > > switch
      > > chip with pin diodes instead. It works all right but I was not able to
      > > achieve the switch times I wanted so I use USB High speed switches
      > > instead.
      > >
      > > If you want a fast switching time and to ensure that no RF feedback
      > > triggers
      > > the diodes, you have to drive them hard. Doing so, may create problems on
      > > very high frequencies due to inductance but hey! on HF bands? Naaah!
      > >
      > > Using pin diodes for switching of the input bandpass filter and for a
      > > QRP PA?
      > > Good idea and it works absolutely fine.
      > >
      > > HOWEVER! Please refrain from taking a dive in your junk box!
      > >
      > > Buy new types and with the voltage spec you requires. For clamping, I
      > > normally
      > > use the BAT60A as it's a very low voltage drop diode ( 0.1 to 0.3V -
      > > BUT! a
      > > Ct of 20pF ) as well as suitable for QRP PA's.
      > >
      > > For serial switching, I use almost any other pin diode like the
      > > HSMP-3894-BLKG
      > > ( a Ct of 0.21pF ).
      > >
      > > On lower frequencies, the "leakage" from a 0.21pF Ct, is not a problem
      > > normally. You will probably have more stray capacitance from a sloppy PCB
      > > design anyway...
      > >
      > > There are a good document to be found on the internet -
      > > pinhandbook.pdf, but I
      > > don't remember where I found it or if it's allowed to be copied to the
      > > public
      > > domain. Mail me directly for a private copy.
      > >
      > > //Dan
      > >
      > > On Sunday 03 December 2006 05:13, Graham Haddock wrote:
      > > > Kees:
      > > >
      > > > 1.) A breakdown voltage appropriate for the voltage/power levels you
      > > > will be switching.
      > > > 2.) A low series on resistance appropriate to minimize losses at the
      > > > impedance/power you are handling.
      > > > 3.) A low series off capacitance to minimize signal leakage when
      > > > biased off.
      > > >
      > > > You didn't say whether you were doing high power transmitter output
      > > > switching or low level receiver or transmitter switching.
      > > >
      > > > --- Graham / KE9H
      > > >
      > > > ==
      > > >
      > > > Kees wrote:
      > > > > Can someone provide information on the best PIN diodes for HF
      > >
      > > operation
      > >
      > > > > if we want to use them for electrical bandswitching. What
      > > > > characteristics do you look for ? Low capacitance, low inductance,
      > >
      > > etc ?
      > >
      > > > > 73 Kees K5BCQ
      > >
      > > --
      > > Dan Andersson, M0DFI
      > > dan@... <mailto:dan%40andersson.co.uk>
      > > dan.andersson@... <mailto:dan.andersson%40ieee.org>

      --
      Dan Andersson, M0DFI
      dan@... dan.andersson@...
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