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Datasheet Jargon Translation Required

Started by Cursitor Doom July 11, 2021
On Wednesday, July 14, 2021 at 6:45:06 PM UTC+10, John Doe wrote:
> Anthony William Sloman <bill....@ieee.org> wrote: > > On Wednesday, July 14, 2021 at 5:29:59 AM UTC+10, John Larkin wrote: > >> On Tue, 13 Jul 2021 08:51:31 +0100, Martin Brown > >> <'''newspam'''@nonad.co.uk> wrote: > >> >On 13/07/2021 01:21, John Larkin wrote: > >> >> On Tue, 13 Jul 2021 10:01:49 +1000, Clifford Heath > >> >> <no....@please.net> wrote: > >> >> > >> >>> On 13/7/21 6:51 am, John Larkin wrote: > >> > > >> >>>> No use trying to help you. > >> >>> > >> >>> Please stop trying to educate it then. This is a creature who still > > > >> >>> thinks resistors must have leads. Fully Neanderthal... > >> >> > >> >> Poles are jargon. > >> > > >> >Poles come from complex analysis representing zeroes in the denominator > > > >> >of a transfer function. Zeroes in the numerator are just called zeros. > > > >> >Electronic engineers have adopted the language of mathematicians here. > >> > >> The LaPlace/pole/zero thing was academic formalism in the pre-computer age. I don't do that stuff any more... just Spice it. > > > > Of course you don't. Getting your head around the academic formalism lets you understand what's going on, and you don't do that. > > > >> That fussy stuff was linear anyhow. The world isn't linear. > > > > Most of us have noticed. The linear bits are easier to understand and manipulate, so they get more attention. > > > >> My profs loved that sort of math. I don't think any of them actually des
igned anything.
> > > > Of course, since John Larkin doesn't actually understand what "design" involves, this isn't a useful observation. > > > >> S-params and Smith charts are arguably similar relics of the graph paper > > and slide-rule days. > > > > S-parameters have been around for a while, as have Smith charts. Visual representation of what's going on do help people develop an understanding of the processes involved, but John Larkin is happy to rely on Darwinian evolution to get him to circuits that work well enough to sell, even if he doesn't understand quite how they work. > > > > A computer is merely an bigger, faster more precise slide-rule and graph paper is a slower form of visual display. Chart recorders were the original data loggers. > > Bozo the Clown...
My thought exactly. John Doe didn't format his post in a way that made this obvious, but it's charitable to make his good intentions clear - the fact that he's an incompetent half-wit shouldn't be allowed to disguise the fact that his heart is in right place, even if his brain went down the toilet years ago. -- Bill Sloman, Sydney
On Wed, 14 Jul 2021 09:09:55 +0100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

>On 13/07/2021 23:18, Cursitor Doom wrote: >> On Tue, 13 Jul 2021 12:23:24 -0700, John Larkin >> <jlarkin@highland_atwork_technology.com> wrote: >> >>> On Tue, 13 Jul 2021 18:46:44 +0100, Cursitor Doom <cd@nowhere.com> >>> wrote: >>> >>>> On Mon, 12 Jul 2021 13:51:36 -0700, John Larkin >>>> <jlarkin@highland_atwork_technology.com> wrote: >>>> >>>>> On Mon, 12 Jul 2021 21:27:09 +0100, Cursitor Doom <cd@nowhere.com> >>>>> wrote: >>>>> >>>>>> On Mon, 12 Jul 2021 21:11:29 +0100, Cursitor Doom <cd@nowhere.com> >>>>>> wrote: >>>>>> >>>>>>> On Sun, 11 Jul 2021 18:18:45 -0700, jlarkin@highlandsniptechnology.com >>>>>>> wrote: >>>>>>> > >>>>>>>> Post a sketch of the circuit. Words don't tell the story. >>>>>>> >>>>>>> It's on page 16 of the datasheet I linked to (diagram 2). Really >>>>>>> couldn't be any simpler; just a case of observing the layout >>>>>>> directions and chosing the right support components for the op-amp >>>>>>> itself. >>>>>>> >>>>>>> https://www.ti.com/lit/ds/symlink/lf356-mil.pdf >>>>>> >>>>>> Or "figure 27" as they also show it as. Bottom of page 16 anyway. >>>>> >>>>> No use trying to help you. >>>> >>>> But you already have! As has Speff and a couple of other worthy >>>> individuals. This is one tiny project I'd rather others didn't design >>>> for me. Spoils all the fun! :-D >>> >>> If you won't post your schematic, then we can't have any fun! >> >> Are you unable to view the diagram at all? Remember those old programs >> we used to use on this group that generated ASCII art representations >> of schematics? Crude but effective and in the days when we had nothing >> else - Invaluable. >> >> So... what's the issue with the diagram I linked to? > >It just shows how to use the chip as a simple inverting amplifier >without having it oscillate like crazy due to stray capacitance at the >input. Which part of make R1*C1=R2*C2 do you not understand? > >The real practical difficulty is matching your dynamic microphone to the >"ideal" amplifier for lowest possible distortion and maximum signal. > >John is asking to see that part - not the gain block after it.
There are all sorts of subtelties about a dynamic mic amp. The inverting opamp is a bad start. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
On Wed, 14 Jul 2021 06:26:16 -0700, jlarkin@highlandsniptechnology.com
wrote:

>On Wed, 14 Jul 2021 09:09:55 +0100, Martin Brown ><'''newspam'''@nonad.co.uk> wrote: > >>On 13/07/2021 23:18, Cursitor Doom wrote: >>> On Tue, 13 Jul 2021 12:23:24 -0700, John Larkin >>> <jlarkin@highland_atwork_technology.com> wrote: >>> >>>> On Tue, 13 Jul 2021 18:46:44 +0100, Cursitor Doom <cd@nowhere.com> >>>> wrote: >>>> >>>>> On Mon, 12 Jul 2021 13:51:36 -0700, John Larkin >>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>> >>>>>> On Mon, 12 Jul 2021 21:27:09 +0100, Cursitor Doom <cd@nowhere.com> >>>>>> wrote: >>>>>> >>>>>>> On Mon, 12 Jul 2021 21:11:29 +0100, Cursitor Doom <cd@nowhere.com> >>>>>>> wrote: >>>>>>> >>>>>>>> On Sun, 11 Jul 2021 18:18:45 -0700, jlarkin@highlandsniptechnology.com >>>>>>>> wrote: >>>>>>>> >> >>>>>>>>> Post a sketch of the circuit. Words don't tell the story. >>>>>>>> >>>>>>>> It's on page 16 of the datasheet I linked to (diagram 2). Really >>>>>>>> couldn't be any simpler; just a case of observing the layout >>>>>>>> directions and chosing the right support components for the op-amp >>>>>>>> itself. >>>>>>>> >>>>>>>> https://www.ti.com/lit/ds/symlink/lf356-mil.pdf >>>>>>> >>>>>>> Or "figure 27" as they also show it as. Bottom of page 16 anyway. >>>>>> >>>>>> No use trying to help you. >>>>> >>>>> But you already have! As has Speff and a couple of other worthy >>>>> individuals. This is one tiny project I'd rather others didn't design >>>>> for me. Spoils all the fun! :-D >>>> >>>> If you won't post your schematic, then we can't have any fun! >>> >>> Are you unable to view the diagram at all? Remember those old programs >>> we used to use on this group that generated ASCII art representations >>> of schematics? Crude but effective and in the days when we had nothing >>> else - Invaluable. >>> >>> So... what's the issue with the diagram I linked to? >> >>It just shows how to use the chip as a simple inverting amplifier >>without having it oscillate like crazy due to stray capacitance at the >>input. Which part of make R1*C1=R2*C2 do you not understand? >> >>The real practical difficulty is matching your dynamic microphone to the >>"ideal" amplifier for lowest possible distortion and maximum signal. >> >>John is asking to see that part - not the gain block after it. > >There are all sorts of subtelties about a dynamic mic amp. The >inverting opamp is a bad start.
Someone on this group suggested that chip as being an ideal, high-impedance, low-distortion, low-noise first stage for a dynamic mic amplifier. If you know of a better one, then by all means feel free to suggest it.
On Wed, 14 Jul 2021 16:39:53 +0100, Cursitor Doom <cd@nowhere.com>
wrote:

>On Wed, 14 Jul 2021 06:26:16 -0700, jlarkin@highlandsniptechnology.com >wrote: > >>On Wed, 14 Jul 2021 09:09:55 +0100, Martin Brown >><'''newspam'''@nonad.co.uk> wrote: >> >>>On 13/07/2021 23:18, Cursitor Doom wrote: >>>> On Tue, 13 Jul 2021 12:23:24 -0700, John Larkin >>>> <jlarkin@highland_atwork_technology.com> wrote: >>>> >>>>> On Tue, 13 Jul 2021 18:46:44 +0100, Cursitor Doom <cd@nowhere.com> >>>>> wrote: >>>>> >>>>>> On Mon, 12 Jul 2021 13:51:36 -0700, John Larkin >>>>>> <jlarkin@highland_atwork_technology.com> wrote: >>>>>> >>>>>>> On Mon, 12 Jul 2021 21:27:09 +0100, Cursitor Doom <cd@nowhere.com> >>>>>>> wrote: >>>>>>> >>>>>>>> On Mon, 12 Jul 2021 21:11:29 +0100, Cursitor Doom <cd@nowhere.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> On Sun, 11 Jul 2021 18:18:45 -0700, jlarkin@highlandsniptechnology.com >>>>>>>>> wrote: >>>>>>>>> >>> >>>>>>>>>> Post a sketch of the circuit. Words don't tell the story. >>>>>>>>> >>>>>>>>> It's on page 16 of the datasheet I linked to (diagram 2). Really >>>>>>>>> couldn't be any simpler; just a case of observing the layout >>>>>>>>> directions and chosing the right support components for the op-amp >>>>>>>>> itself. >>>>>>>>> >>>>>>>>> https://www.ti.com/lit/ds/symlink/lf356-mil.pdf >>>>>>>> >>>>>>>> Or "figure 27" as they also show it as. Bottom of page 16 anyway. >>>>>>> >>>>>>> No use trying to help you. >>>>>> >>>>>> But you already have! As has Speff and a couple of other worthy >>>>>> individuals. This is one tiny project I'd rather others didn't design >>>>>> for me. Spoils all the fun! :-D >>>>> >>>>> If you won't post your schematic, then we can't have any fun! >>>> >>>> Are you unable to view the diagram at all? Remember those old programs >>>> we used to use on this group that generated ASCII art representations >>>> of schematics? Crude but effective and in the days when we had nothing >>>> else - Invaluable. >>>> >>>> So... what's the issue with the diagram I linked to? >>> >>>It just shows how to use the chip as a simple inverting amplifier >>>without having it oscillate like crazy due to stray capacitance at the >>>input. Which part of make R1*C1=R2*C2 do you not understand? >>> >>>The real practical difficulty is matching your dynamic microphone to the >>>"ideal" amplifier for lowest possible distortion and maximum signal. >>> >>>John is asking to see that part - not the gain block after it. >> >>There are all sorts of subtelties about a dynamic mic amp. The >>inverting opamp is a bad start. > >Someone on this group suggested that chip as being an ideal, >high-impedance, low-distortion, low-noise first stage for a dynamic >mic amplifier. If you know of a better one, then by all means feel >free to suggest it.
Start with the specs for the mic. -- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
John Larkin wrote:
> On Tue, 13 Jul 2021 08:51:31 +0100, Martin Brown > <'''newspam'''@nonad.co.uk> wrote: > >> On 13/07/2021 01:21, John Larkin wrote: >>> On Tue, 13 Jul 2021 10:01:49 +1000, Clifford Heath >>> <no.spam@please.net> wrote: >>> >>>> On 13/7/21 6:51 am, John Larkin wrote: >> >>>>> No use trying to help you. >>>> >>>> Please stop trying to educate it then. This is a creature who still >>>> thinks resistors must have leads. Fully Neanderthal... >>> >>> Poles are jargon. >> >> Poles come from complex analysis representing zeroes in the denominator >> of a transfer function. Zeroes in the numerator are just called zeros. >> Electronic engineers have adopted the language of mathematicians here. > > The LaPlace/pole/zero thing was academic formalism in the pre-computer > age. I don't do that stuff any more... just Spice it.
Nah, algebra rocks. One good sleazy approximation is worth a stack of SPICE output. ;)
> > That fussy stuff was linear anyhow. The world isn't linear.
I try to make it that way, usually with some success.
> > My profs loved that sort of math. I don't think any of them actually > designed anything. > > S-params and Smith charts are arguably similar relics of the graph > paper and slide-rule days.
Knowing Smith charts is a huge labour saver for RF things. They're especially good for synthesis of narrow-to-moderate bandwidth things. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
On Wed, 14 Jul 2021 13:20:00 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

>John Larkin wrote: >> On Tue, 13 Jul 2021 08:51:31 +0100, Martin Brown >> <'''newspam'''@nonad.co.uk> wrote: >> >>> On 13/07/2021 01:21, John Larkin wrote: >>>> On Tue, 13 Jul 2021 10:01:49 +1000, Clifford Heath >>>> <no.spam@please.net> wrote: >>>> >>>>> On 13/7/21 6:51 am, John Larkin wrote: >>> >>>>>> No use trying to help you. >>>>> >>>>> Please stop trying to educate it then. This is a creature who still >>>>> thinks resistors must have leads. Fully Neanderthal... >>>> >>>> Poles are jargon. >>> >>> Poles come from complex analysis representing zeroes in the denominator >>> of a transfer function. Zeroes in the numerator are just called zeros. >>> Electronic engineers have adopted the language of mathematicians here. >> >> The LaPlace/pole/zero thing was academic formalism in the pre-computer >> age. I don't do that stuff any more... just Spice it. > >Nah, algebra rocks. One good sleazy approximation is worth a stack of >SPICE output. ;)
I can do sleazy approximations in my head! Guess, Spice, iterate. That works until the complexity gets lost in space, which happens once in a while. Filters are one example... but hardly anybody designs filters with math; we use Williams or Filterpro or the NuHertz software.
> >> >> That fussy stuff was linear anyhow. The world isn't linear. > >I try to make it that way, usually with some success. > >> >> My profs loved that sort of math. I don't think any of them actually >> designed anything. >> >> S-params and Smith charts are arguably similar relics of the graph >> paper and slide-rule days. > >Knowing Smith charts is a huge labour saver for RF things. They're >especially good for synthesis of narrow-to-moderate bandwidth things.
Yes, narrowband and small-signal. But if you have a data sheet with all that classic stuff, it's pretty much useless for fast, nonlinear, time domain problems. Or even high-level RF. On the other hand, a good Spice model would do for both. "Load pull" testing was the classic way to work around s-params. Just try it.
On 14/07/2021 14:26, jlarkin@highlandsniptechnology.com wrote:
> On Wed, 14 Jul 2021 09:09:55 +0100, Martin Brown > <'''newspam'''@nonad.co.uk> wrote: > >> On 13/07/2021 23:18, Cursitor Doom wrote:
>>> So... what's the issue with the diagram I linked to? >> >> It just shows how to use the chip as a simple inverting amplifier >> without having it oscillate like crazy due to stray capacitance at the >> input. Which part of make R1*C1=R2*C2 do you not understand? >> >> The real practical difficulty is matching your dynamic microphone to the >> "ideal" amplifier for lowest possible distortion and maximum signal. >> >> John is asking to see that part - not the gain block after it. > > There are all sorts of subtelties about a dynamic mic amp. The > inverting opamp is a bad start.
I'd have expected something more like an instrumentation amplifier configuration to take out common mode noise and a few discretes on the front end to do phantom power and initial signal conditioning. This example looks to me like it might possibly satisfy the OP's unspecified requirements. The topology looks about right to me. http://www.cordellaudio.com/preamplifiers/dynamicmicpreamp.shtml -- Regards, Martin Brown
On Wed, 14 Jul 2021 20:31:31 +0100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

>On 14/07/2021 14:26, jlarkin@highlandsniptechnology.com wrote: >> On Wed, 14 Jul 2021 09:09:55 +0100, Martin Brown >> <'''newspam'''@nonad.co.uk> wrote: >> >>> On 13/07/2021 23:18, Cursitor Doom wrote: > >>>> So... what's the issue with the diagram I linked to? >>> >>> It just shows how to use the chip as a simple inverting amplifier >>> without having it oscillate like crazy due to stray capacitance at the >>> input. Which part of make R1*C1=R2*C2 do you not understand? >>> >>> The real practical difficulty is matching your dynamic microphone to the >>> "ideal" amplifier for lowest possible distortion and maximum signal. >>> >>> John is asking to see that part - not the gain block after it. >> >> There are all sorts of subtelties about a dynamic mic amp. The >> inverting opamp is a bad start. > >I'd have expected something more like an instrumentation amplifier >configuration to take out common mode noise and a few discretes on the >front end to do phantom power and initial signal conditioning. > >This example looks to me like it might possibly satisfy the OP's >unspecified requirements. The topology looks about right to me. > >http://www.cordellaudio.com/preamplifiers/dynamicmicpreamp.shtml
We have no idea what he wants to do. It's basic that more transistors make more noise, and an opamp or diffamp starts with at least two in the front end. The ancient jfet thing is really bad. But a creative design will make it worse. Do microphones have significant Brownian noise, from air molecules bashing the diaphragm?
On Wednesday, July 14, 2021 at 12:43:07 PM UTC-7, John Larkin wrote:
> On Wed, 14 Jul 2021 20:31:31 +0100, Martin Brown > <'''newspam'''@nonad.co.uk> wrote: > >This example looks to me like it might possibly satisfy the OP's > >unspecified requirements. The topology looks about right to me. > > > >http://www.cordellaudio.com/preamplifiers/dynamicmicpreamp.shtml > We have no idea what he wants to do. > > It's basic that more transistors make more noise, and an opamp or > diffamp starts with at least two in the front end. > > The ancient jfet thing is really bad. But a creative design will make > it worse.
The figure of merit is signal/noise ratio, not noise. So, you should start with impedance matching (and a grounded-base BJT might actually win). JFET designs have good character compared to old MOS (because of surface recombination), but that's process-dependent so MOS might be better nowadays.
> Do microphones have significant Brownian noise, from air molecules > bashing the diaphragm?
Yes, of course. So do your ears. Listen to a conch shell lately?
John Doe <always.look@message.header> wrote in
news:scm86b$7cn$1@dont-email.me: 

> Subject: Re: Datasheet Jargon Translation Required > From: John Doe <always.look@message.header> > Newsgroups: sci.electronics.design,free.spam > > "the concepts "male" and "female" are essentially social > constructions" (Bill Sloman) > > Bozo the Clown... >
You got nothing, you stupid fuck. That is why *this* stupid shit is all you can post. You couldn't muster an intelligent post if you tried.