Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bill Sloman Newsgroups: sci.electronics.design Subject: Re: another fast one-shot Date: Thu, 13 Jun 2024 16:03:04 +1000 Organization: A noiseless patient Spider Lines: 176 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Thu, 13 Jun 2024 08:03:18 +0200 (CEST) Injection-Info: dont-email.me; posting-host="061ca8130ff89dd3f636ba4bb4f8d77d"; logging-data="2245869"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19KTATzzCeSs0H9a2RkDsEB6YcXEsAG3Qs=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:2O5E5uVPytKMT4e8Md9gqfqoJQ4= Content-Language: en-US In-Reply-To: X-Antivirus: Norton (VPS 240612-4, 12/6/2024), Outbound message X-Antivirus-Status: Clean Bytes: 6167 On 13/06/2024 4:11 am, john larkin wrote: > On Wed, 12 Jun 2024 17:22:49 -0000 (UTC), Cursitor Doom > wrote: > >> On Wed, 12 Jun 2024 09:33:17 -0700, john larkin wrote: >> >>> Here's another idea for a fast one-shot. This is the just-apply-money >>> version and should get close to 1 ns pulse width and should easily >>> trigger at 150 MHz. >>> >>> https://www.dropbox.com/scl/fi/1okfo8964bw5m53mjmxs6/ >> Pecl_One_Shot_1.jpg?rlkey=dwus6qjyqsynl2rv6uje2xxtj&raw=1 >>> >>> I can use the other half of the dual comparator elsewhere. This one has >>> programmable hysteresis too. >> >> Exposing my contemptworthy ignorance here no doubt, but what exactly is it >> that is fast about this design, John? And what would its application be? > > It would have a leading-edge prop delay of 350 ps, a minimum pulse > width just over 1 ns, and would easily trigger at 150 MHz. Integrated > one-shots, xxx123 types, are always terrible, even the obsolete ECL > ones. > > It would be a programmable delay in a number of possible products, > including some optical modulators. Just playing right now. > > More dollars could certainly do something faster, but as long as > customers connect boxes with cables, faster isn't worth a lot. Light > just moves too slow. > > Any suggestions for a faster one-shot? Version 4 SHEET 1 2924 1040 WIRE -592 -720 -768 -720 WIRE 128 -720 -592 -720 WIRE 304 -720 128 -720 WIRE 768 -720 304 -720 WIRE 976 -720 768 -720 WIRE 1488 -576 1488 -720 WIRE 128 -560 128 -720 WIRE 304 -560 304 -720 WIRE 768 -560 768 -720 WIRE -592 -384 -592 -720 WIRE 1072 -368 1072 -400 WIRE 768 -320 768 -480 WIRE 960 -320 768 -320 WIRE 1008 -320 960 -320 WIRE 128 -288 128 -480 WIRE 176 -288 128 -288 WIRE 576 -288 240 -288 WIRE 768 -208 768 -320 WIRE 304 -160 304 -480 WIRE 400 -160 304 -160 WIRE 576 -160 576 -288 WIRE 576 -160 480 -160 WIRE 640 -160 576 -160 WIRE 704 -160 640 -160 WIRE -768 -64 -768 -720 WIRE 128 48 128 -288 WIRE -272 96 -432 96 WIRE 64 96 -192 96 WIRE 640 128 640 -160 WIRE 304 160 304 -160 WIRE -432 240 -432 96 WIRE -768 416 -768 16 WIRE -768 416 -880 416 WIRE -736 416 -768 416 WIRE -592 416 -592 -320 WIRE -592 416 -736 416 WIRE -496 416 -592 416 WIRE -432 416 -432 320 WIRE -432 416 -496 416 WIRE 640 416 640 208 WIRE 640 416 -432 416 WIRE 1072 416 640 416 WIRE 128 464 128 144 WIRE 768 464 768 -112 WIRE 768 464 128 464 WIRE -880 496 -880 416 WIRE 768 496 768 464 WIRE -736 640 -736 416 WIRE -496 640 -496 416 WIRE -736 656 -736 640 WIRE -736 944 -736 720 WIRE -496 944 -496 704 WIRE -496 944 -736 944 WIRE 304 944 304 240 WIRE 304 944 -496 944 WIRE 768 944 768 576 WIRE 768 944 304 944 WIRE 1760 944 768 944 FLAG -880 496 0 FLAG 960 -320 out SYMBOL npn 64 48 R0 SYMATTR InstName Q1 SYMATTR Value BFR92A SYMBOL npn 704 -208 R0 SYMATTR InstName Q2 SYMATTR Value BFR92A SYMBOL voltage -768 -80 R0 WINDOW 123 0 0 Left 0 WINDOW 39 24 44 Left 2 SYMATTR SpiceLine Rser=0.1 SYMATTR InstName V1 SYMATTR Value 5.0 SYMBOL voltage -736 624 R0 WINDOW 123 0 0 Left 0 WINDOW 39 24 44 Left 2 SYMATTR SpiceLine Rser=0.1 SYMATTR InstName V2 SYMATTR Value 4.5 SYMBOL voltage -432 224 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value PULSE(0 0.2 1n 300p 300p 100p 200n 2) SYMBOL res -176 80 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 22 SYMBOL res 752 480 R0 SYMATTR InstName R3 SYMATTR Value 360 SYMBOL res 112 -576 R0 SYMATTR InstName R4 SYMATTR Value 180 SYMBOL res 624 112 R0 SYMATTR InstName R5 SYMATTR Value 43 SYMBOL res 752 -576 R0 SYMATTR InstName R6 SYMATTR Value 180 SYMBOL res 288 -576 R0 SYMATTR InstName R2 SYMATTR Value 1k SYMBOL cap 240 -304 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 3.3p SYMBOL res 288 144 R0 SYMATTR InstName R7 SYMATTR Value 1k2 SYMBOL res 496 -176 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R13 SYMATTR Value 43 SYMBOL cap -608 -384 R0 SYMATTR InstName C3 SYMATTR Value 10n SYMBOL cap -512 640 R0 SYMATTR InstName C4 SYMATTR Value 10n TEXT -272 1000 Left 2 !.model BFR92A NPN(IS=0.1213E-15 VAF=30 BF=94.73 IKF=0.46227 XTB=0 BR=10.729 CJC=946.47E-15 CJE=10.416E-15 TR=1.2744E-9 TF=26.796E-12 ITF=0.0044601 VTF=0.32861 XTF=0.3817 RB=14.998 RC=0.13793 RE=0.29088 Vceo=15 Icrating=4m mfg=Infineon) TEXT -904 1024 Left 2 !.tran 0 500n 0 It's just a two transistor emitter-coupled monostable, but with the two transistors as BFR92's run at 10mA, it produces 1nsec pulse without fuss. Finding the broad-band PNPs to let you translate the output pulse to a useful voltage level is tricky. Phil Hobbs has told us that there is a least one still in production and available. -- Bill Sloman, Sydney -- This email has been checked for viruses by Norton antivirus software. www.norton.com