I don't believe these are RF detectors, they look like switching diodes. Even though they are Shottkys, the spec says they have a 5nS reverse recovery time ???
That would be too slow for a 1 GHz counter. I use a lot of BAV99, and while not being Shottkys, they have about the same reverse recovery and 15% of the capacitance. Didier KO4BB > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Keith Payea > Sent: Monday, March 31, 2008 10:05 PM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Adding prescaler to HP 5334B > > My usual choice for dual schottky in an SOT-23 is the BAT54. > It comes in four flavors: > > BAT54 - single diode > BAT54A - Common Anode > BAT54C - Common Cathode > BAT54S - Series > > It's rated at 30V/200mA. > > Keith > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Didier Juges > Sent: Monday, March 31, 2008 7:56 PM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Adding prescaler to HP 5334B > > 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. > > > _______________________________________________ > 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.