Path: ...!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Sat, 22 Jun 2024 05:20:30 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: Re: another fast one-shot Date: Fri, 21 Jun 2024 22:20:31 -0700 Message-ID: <6cmc7j1u7uaaubat2klfqgv3gmibvp6t3j@4ax.com> References: User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 196 X-Trace: sv3-A0xkmGKmXuWbzOBx+zwN9L2WoCD+d6Igkm6Z/xuKl4Zt5FyCYqpeU+Eb5/KQpudHamQwmOch7s3VFE4!xYemUmZVsl3WG3G61t/ZK5fJdIuHkTaka+QVr23Qu21Xzi0MQR33dJVtpm6Gq+5FhjdWHs96rL9f!KlLLNQ== 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: 7682 On Sat, 22 Jun 2024 13:13:44 +1000, Bill Sloman wrote: >On 14/06/2024 1:31 am, john larkin wrote: >> 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. >> >> 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 ==========