I was thinking of buying a few dual shottkys (series configuration) in SOT-23 package and I thought it would be a piece of cake finding those, but interestingly, my usual part vendors (Digikey, Mouser, Newark, Allied) don't carry any that I could use, at least if they do, I did not find them.
Anyone has recommendations for such an animal? Didier KO4BB > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bruce Griffiths > Sent: Monday, March 31, 2008 8:37 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Adding prescaler to HP 5334B > > Bruce Griffiths wrote: > > Robert Berg wrote: > > > >> Having seen it discussed, I was wondering whether anyone > has actually > >> added the Schottky diodes and prescaler chip to a 5334B to > provide a > >> C-channel input. The matched Schottky quads (5082-2831) > are no longer > >> available, and even the recommended replacements (5082-2303) seem > >> scarce. Was thinking of trying 1N5711s, which can be obtained as > >> matched sets, although probably not on my budget. How > critical is the > >> need to use matched sets? The NEC UPB1507GV-ACT-ND looks promising > >> for the prescaler, if the small form factor isn't too > minute to handle. > >> > >> Bob > >> WA7ZRX > >> > >> > > Not particularly critical as they are only used as clamps > to limit the > > input signal to the 30dB gain preamplifier. > > You may be able to use a single pair instead, albeit with a lower > > input damage level. > > Using a quad allows the clamp current to be shared between > a pair of > > diodes, however some matching is required to ensure > effective current > > sharing. > > Too much diode shunt capacitance will limit the bandwidth. > > > > Bruce > > > Quad CR303 acts as a clamp, Quad CR302 acts as a detector > with temperature compensation. > Only 2 diodes in CR302 are used so CR302 can be replaced by a > matched pair. > > Try using low barrier microwave specified schottky diodes > with lower capacitance than a 1N5711. > > Bruce > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, > go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > Internal Virus Database is out-of-date. > Checked by AVG. > Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release > Date: 3/22/2008 4:43 PM > > Internal Virus Database is out-of-date. Checked by AVG. Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release Date: 3/22/2008 4:43 PM _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.