Path: ...!local-4.nntp.ord.giganews.com!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Sat, 22 Jun 2024 05:23:29 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: Re: another fast one-shot Date: Fri, 21 Jun 2024 22:23:30 -0700 Message-ID: References: User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 186 X-Trace: sv3-JVVKMnOv2jTxsTB6h2F+ObTORgNajflfT6JzkN5GLcUDwVC1pA9W1yoTotRhOOMYpSZgo7Jdw90jUHC!UXgQV7nD5X/6WMd7NWXcoOwLwNNVFljTXS4HzGmz9wgNttvnr/ews1Ppp8S0RF5WDA0k4VGUtXA/!rQyoXA== X-Complaints-To: www.supernews.com/docs/abuse.html X-DMCA-Complaints-To: www.supernews.com/docs/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Bytes: 6907 On Fri, 14 Jun 2024 19:02:11 +0100, piglet wrote: >On 13/06/2024 07:03, Bill Sloman wrote: >> 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. >> > >It is a pity it relies on an input pulse shorter than the output - at >those speeds it would nicer to have a step input somehow? > ========== REMAINDER OF ARTICLE TRUNCATED ==========