Path: ...!Xl.tags.giganews.com!local-1.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Thu, 13 Jun 2024 15:31:05 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: Re: another fast one-shot Date: Thu, 13 Jun 2024 08:31:06 -0700 Message-ID: References: User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 182 X-Trace: sv3-mLQILDPWvUgGnC74w541BLERaYfTRRr/TbODlricF0K5k0jxodnrvFB4QPfg8ai6eu7xnxCBLFWuJFY!tUu6dL4zfiiDSvFeJVyu2yuLBrPjR/aRoO2AtaZhOUcdHUODJSY6EXSV7Hx7TE3dZtemesE6ZmWB!cu0WlA== 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: 6464 On Thu, 13 Jun 2024 16:03:04 +1000, 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. > >-- >Bill Sloman, Sydney What a mess. The output pulse width just follows the input pulse width. Unless you change C1, in which case it oscillates. ========== REMAINDER OF ARTICLE TRUNCATED ==========