Path: ...!local-4.nntp.ord.giganews.com!Xl.tags.giganews.com!local-2.nntp.ord.giganews.com!nntp.supernews.com!news.supernews.com.POSTED!not-for-mail NNTP-Posting-Date: Fri, 14 Jun 2024 16:33:43 +0000 From: john larkin Newsgroups: sci.electronics.design Subject: Re: Fast monostable with a transistpor array Date: Fri, 14 Jun 2024 09:33:43 -0700 Message-ID: References: <8epo6jhf5k5nbkkqp5ot9b6nq1lhoia870@4ax.com> User-Agent: ForteAgent/8.00.32.1272 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 73 X-Trace: sv3-vvhf1hEUXYwYRk/dSKwRKpTA1tBOMWovVnV6Un7FXr0TBbv7hcXfb5Pp29H8WIbNDszHK4Ge2gmV9y/!dAXj/yPNBNi4iSmRV7y83ic6rMssB6n6D9DObnavswJsIKCfMN0gmHp5XVNA6Ta3NMF1k7L+VQGd!YUcd9w== 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: 4223 On Fri, 14 Jun 2024 12:18:23 -0400, "Edward Rawde" wrote: >"john larkin" wrote in message news:8epo6jhf5k5nbkkqp5ot9b6nq1lhoia870@4ax.com... >> On Fri, 14 Jun 2024 11:08:56 -0400, "Edward Rawde" >> wrote: >> >>> >>>"john larkin" wrote in message news:hilo6j9dgctalpiu4v09rpdavf6fetm1cv@4ax.com... >>>> On Thu, 13 Jun 2024 23:25:37 -0400, "Edward Rawde" >>>> wrote: >>>> >>>>>"Bill Sloman" wrote in message news:v4f2nm$2augj$1@dont-email.me... >>>>>> One option John Larjkin doesn't seem to have explored is using Renesas HFA3096 five transistor array as basis for his >>>>>> mononstable >>>>>> and level shifter. >>>>>> >>>>>> It offers three 8GHz NPN parts and two 5.5GHz PNP parts in a single array. >>>>>> >>>>>> https://www.renesas.com/us/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet?r=494216 >>>>>> >>>>> >>>>>I put the NPN model parameters into a circuit designed by yourself. >>>>>It's late now but I got as far as Time step too small. >>>>> >>>> >>>> That is neither fast nor a monostable. >>> >>>Yes ok it's an astable and certainly not intended to be fast. >>>It was intended only to see if the model worked. Nothing more. >> >> It doesn't work! >> >>> >>>> >>>> There's no reason to use many-GHz parts in micropower circuits. One >>>> reason is that the sim breaks. >> >> Most versions of the HFA3046 are obsolete. The only one left at >> Digikey costs $12. It would be risky to design around that part. > >If it's obsolete or going obsolete then yes it would make no sense to use it. >I would guess that you get to do plenty of work because a manufacturer has suddenly decided to discontinue a part. > >> Wasn't HFA originally a Harris part? >> >> There are lots of dual (non-monolithic) diodes and bipolars and fets >> around, but the monolithic arrays are mostly gone. > >What part would you recommend (single or dual) and does it have a working LTSpice model? Just pull up some parts from the standard library, some low current NPNs like BC547 maybe. Look for low capacitances if you care about that; the HFAs are good in that respect. Why do people avoid making clean 4-wire connections on schematics? > >> >> The duals save space, but aren't well matched so are electrically and >> thermally equivalent to buying two separate parts. >> >> I wonder if one could design really fast stuff with the HFA3046. >> Package parasitics look nasty. And the big package will force ugly PCB >> routing. You can plop a single tiny transistor wherever you want. > >Yes that is certainly an advantage of single transistors. >Is a suitable single transistor still available for use in new designs? There are zillions of single transistors around. I like BCX70 as an npn gumdrop, although I use mosfets more often for simple things.