On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote:> On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: > > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: > > > Hi all > > > > > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. > > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? > > > > > > How do I search for such ones? > > > > > > An ordinary opamp does not fit my need, as my application could balance itself > > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. > No part is cheap if it takes up space on a crowded board. > > Many Greenpak devices have comparators in them, but few have opamps.I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. WTF you think a part like this just might be for? https://www.ti.com/lit/ds/symlink/lm392-n.pdf> > -- > > Rick C. > > +- Get 1,000 miles of free Supercharging > +- Tesla referral code - https://ts.la/richard11209
Comparator with driver output
Started by ●November 17, 2022
Reply by ●November 19, 20222022-11-19
Reply by ●November 19, 20222022-11-19
On Saturday, November 19, 2022 at 6:04:05 AM UTC-5, Fred Bloggs wrote:> On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: > > On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: > > > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: > > > > Hi all > > > > > > > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. > > > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? > > > > > > > > How do I search for such ones? > > > > > > > > An ordinary opamp does not fit my need, as my application could balance itself > > > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. > > No part is cheap if it takes up space on a crowded board. > > > > Many Greenpak devices have comparators in them, but few have opamps. > I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. > > WTF you think a part like this just might be for? > > https://www.ti.com/lit/ds/symlink/lm392-n.pdfWhat are you talking about??? I like that you picked a part that comes in tiny packages, like DIPs. Even the SOIC is a large package these days. Figure 1. SOIC and PDIP Packages WTF is going on with you? An opamp and a comparator is always going be a larger package than a simple comparator that does the job. -- Rick C. ++ Get 1,000 miles of free Supercharging ++ Tesla referral code - https://ts.la/richard11209
Reply by ●November 19, 20222022-11-19
On Sat, 19 Nov 2022 03:04:01 -0800 (PST), Fred Bloggs <bloggs.fredbloggs.fred@gmail.com> wrote:>On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: >> On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: >> > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: >> > > Hi all >> > > >> > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. >> > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? >> > > >> > > How do I search for such ones? >> > > >> > > An ordinary opamp does not fit my need, as my application could balance itself >> > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. >> No part is cheap if it takes up space on a crowded board. >> >> Many Greenpak devices have comparators in them, but few have opamps. > >I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. > >WTF you think a part like this just might be for? > >https://www.ti.com/lit/ds/symlink/lm392-n.pdfBeware note 5!
Reply by ●November 19, 20222022-11-19
sonnic...@gmail.com wrote:> Hi all > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector > output. Does the group know about comparators with driver output, hence can > pull up and down, and output like an ordinary opamp? > > How do I search for such ones? > > An ordinary opamp does not fit my need, as my application could balance > itselfWhat do you mean with "could balance itself?" I once needed to drive a cheap, slow 24V H-bridge using a logic output. I ended up using an LM324, with two pairs of paralleled amps wired as comparators for more drive capability. Probably the only thing I ever used an 324 for.
Reply by ●November 19, 20222022-11-19
On Saturday, November 19, 2022 at 12:03:50 PM UTC-5, Ricky wrote:> On Saturday, November 19, 2022 at 6:04:05 AM UTC-5, Fred Bloggs wrote: > > On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: > > > On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: > > > > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: > > > > > Hi all > > > > > > > > > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. > > > > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? > > > > > > > > > > How do I search for such ones? > > > > > > > > > > An ordinary opamp does not fit my need, as my application could balance itself > > > > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. > > > No part is cheap if it takes up space on a crowded board. > > > > > > Many Greenpak devices have comparators in them, but few have opamps. > > I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. > > > > WTF you think a part like this just might be for? > > > > https://www.ti.com/lit/ds/symlink/lm392-n.pdf > What are you talking about??? > > I like that you picked a part that comes in tiny packages, like DIPs. Even the SOIC is a large package these days. > > Figure 1. SOIC and PDIP Packages > > WTF is going on with you? An opamp and a comparator is always going be a larger package than a simple comparator that does the job. > > -- > > Rick C. > > ++ Get 1,000 miles of free Supercharging > ++ Tesla referral code - https://ts.la/richard11209https://vendor.ultralibrarian.com/TI/embedded/?gpn=LM392&package=DGK&pin=8&sid=&c=1 https://www.ti.com/lit/ml/mpds028d/mpds028d.pdf?ts=1668889533066&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM392 Dimensions mm, multiply by 0.04 ( or 0.039) to convert to inches. 3.00mm longest dimension looks pretty small to me. Lots of very delicate precision applications here: https://www.ti.com/lit/an/snoa667b/snoa667b.pdf?ts=1668889907980&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM392 There's plenty of stock out there. Seems a bit pricey at $1.50- not sure if that's another "supply chain" issue or it was always that way. Price is slow to come down in quantity. Makes no difference to a "one-off" project.
Reply by ●November 19, 20222022-11-19
On Saturday, November 19, 2022 at 12:15:47 PM UTC-5, John Larkin wrote:> On Sat, 19 Nov 2022 03:04:01 -0800 (PST), Fred Bloggs > <bloggs.fred...@gmail.com> wrote: > > >On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: > >> On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: > >> > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: > >> > > Hi all > >> > > > >> > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. > >> > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? > >> > > > >> > > How do I search for such ones? > >> > > > >> > > An ordinary opamp does not fit my need, as my application could balance itself > >> > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. > >> No part is cheap if it takes up space on a crowded board. > >> > >> Many Greenpak devices have comparators in them, but few have opamps. > > > >I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. > > > >WTF you think a part like this just might be for? > > > >https://www.ti.com/lit/ds/symlink/lm392-n.pdf > Beware note 5!LOL- I'm aware of that one. A powered down circuit with input signals coming from the external world is a similar gotcha.
Reply by ●November 19, 20222022-11-19
On Sat, 19 Nov 2022 12:43:43 -0800 (PST), Fred Bloggs <bloggs.fredbloggs.fred@gmail.com> wrote:>On Saturday, November 19, 2022 at 12:15:47 PM UTC-5, John Larkin wrote: >> On Sat, 19 Nov 2022 03:04:01 -0800 (PST), Fred Bloggs >> <bloggs.fred...@gmail.com> wrote: >> >> >On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: >> >> On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: >> >> > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: >> >> > > Hi all >> >> > > >> >> > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. >> >> > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? >> >> > > >> >> > > How do I search for such ones? >> >> > > >> >> > > An ordinary opamp does not fit my need, as my application could balance itself >> >> > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. >> >> No part is cheap if it takes up space on a crowded board. >> >> >> >> Many Greenpak devices have comparators in them, but few have opamps. >> > >> >I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. >> > >> >WTF you think a part like this just might be for? >> > >> >https://www.ti.com/lit/ds/symlink/lm392-n.pdf >> Beware note 5! > >LOL- I'm aware of that one. A powered down circuit with input signals coming from the external world is a similar gotcha.That whole generation - LM324, LM339 - got crazy if any input went a little negative. Crazy between sections. And an LM324 opamp makes a horrible comparator, because internal current sources are shared among four opamps. That whole generation is nasty.
Reply by ●November 19, 20222022-11-19
John Larkin wrote:> On Sat, 19 Nov 2022 03:04:01 -0800 (PST), Fred Bloggs > <bloggs.fredbloggs.fred@gmail.com> wrote: > >> On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: >>> On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: >>>> On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: >>>>> Hi all >>>>> >>>>> A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. >>>>> Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? >>>>> >>>>> How do I search for such ones? >>>>> >>>>> An ordinary opamp does not fit my need, as my application could balance itself >>>> You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. >>> No part is cheap if it takes up space on a crowded board. >>> >>> Many Greenpak devices have comparators in them, but few have opamps. >> >> I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. >> >> WTF you think a part like this just might be for? >> >> https://www.ti.com/lit/ds/symlink/lm392-n.pdf > > Beware note 5! >Yup. It's a glorified LM358--Which Is Fiiiinnne. Cheers Phil Hobbs (LM358 fan) -- 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
Reply by ●November 19, 20222022-11-19
John Larkin wrote:> On Sat, 19 Nov 2022 12:43:43 -0800 (PST), Fred Bloggs > <bloggs.fredbloggs.fred@gmail.com> wrote: > >> On Saturday, November 19, 2022 at 12:15:47 PM UTC-5, John Larkin wrote: >>> On Sat, 19 Nov 2022 03:04:01 -0800 (PST), Fred Bloggs >>> <bloggs.fred...@gmail.com> wrote: >>> >>>> On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: >>>>> On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: >>>>>> On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: >>>>>>> Hi all >>>>>>> >>>>>>> A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. >>>>>>> Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? >>>>>>> >>>>>>> How do I search for such ones? >>>>>>> >>>>>>> An ordinary opamp does not fit my need, as my application could balance itself >>>>>> You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. >>>>> No part is cheap if it takes up space on a crowded board. >>>>> >>>>> Many Greenpak devices have comparators in them, but few have opamps. >>>> >>>> I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. >>>> >>>> WTF you think a part like this just might be for? >>>> >>>> https://www.ti.com/lit/ds/symlink/lm392-n.pdf >>> Beware note 5! >> >> LOL- I'm aware of that one. A powered down circuit with input signals coming from the external world is a similar gotcha. > > That whole generation - LM324, LM339 - got crazy if any input went a > little negative. Crazy between sections. > > And an LM324 opamp makes a horrible comparator, because internal > current sources are shared among four opamps. > > That whole generation is nasty.The original 324 had that problem, but IIRC the 324A has separate bias generators for each section. One shining virtue of those parts is that the inputs are lateral PNPs. "Wait a minute", I hear you cry--"Laterals are super slow and have crappy beta!" Yes, it's all true, but their BV_EBO is like 40V, so you can run the inputs way above the supply voltage with no issues. Below ground, not so much. ;) 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
Reply by ●November 19, 20222022-11-19
On Saturday, November 19, 2022 at 3:41:59 PM UTC-5, Fred Bloggs wrote:> On Saturday, November 19, 2022 at 12:03:50 PM UTC-5, Ricky wrote: > > On Saturday, November 19, 2022 at 6:04:05 AM UTC-5, Fred Bloggs wrote: > > > On Saturday, November 19, 2022 at 2:34:34 AM UTC-5, Ricky wrote: > > > > On Friday, November 18, 2022 at 9:15:53 PM UTC-5, Fred Bloggs wrote: > > > > > On Thursday, November 17, 2022 at 3:20:08 PM UTC-5, sonnic...@gmail.com wrote: > > > > > > Hi all > > > > > > > > > > > > A standard comparator f.x LM393, LM2903 etc commonly have a open-collector output. > > > > > > Does the group know about comparators with driver output, hence can pull up and down, and output like an ordinary opamp? > > > > > > > > > > > > How do I search for such ones? > > > > > > > > > > > > An ordinary opamp does not fit my need, as my application could balance itself > > > > > You could use an op amp to buffer the LM393 OC output. Two cheap parts are still cheap. The super fast comparators mentioned are all very fussy about layout and have self-oscillation problems if you're not careful about every little thing. > > > > No part is cheap if it takes up space on a crowded board. > > > > > > > > Many Greenpak devices have comparators in them, but few have opamps. > > > I just want to say I am so thankful to have you around to set me straight. Well, my word, what could I do without you. > > > > > > WTF you think a part like this just might be for? > > > > > > https://www.ti.com/lit/ds/symlink/lm392-n.pdf > > What are you talking about??? > > > > I like that you picked a part that comes in tiny packages, like DIPs. Even the SOIC is a large package these days. > > > > Figure 1. SOIC and PDIP Packages > > > > WTF is going on with you? An opamp and a comparator is always going be a larger package than a simple comparator that does the job. > > > > -- > > > > Rick C. > > > > ++ Get 1,000 miles of free Supercharging > > ++ Tesla referral code - https://ts.la/richard11209 > https://vendor.ultralibrarian.com/TI/embedded/?gpn=LM392&package=DGK&pin=8&sid=&c=1 > > https://www.ti.com/lit/ml/mpds028d/mpds028d.pdf?ts=1668889533066&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM392 > > Dimensions mm, multiply by 0.04 ( or 0.039) to convert to inches. > > 3.00mm longest dimension looks pretty small to me.Again, I ask WTF is wrong with you? The LM392-N does not come in the DCK package according to the data sheet you linked to. SOIC-8 which is 5x6 mm. It is trivial to find a comparator in a SOT-23-6 package, much smaller. Do you pay attention to your own posts? I guess that just slipped by, that happens to all of us.> Lots of very delicate precision applications here: > > https://www.ti.com/lit/an/snoa667b/snoa667b.pdf?ts=1668889907980&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM392 > > There's plenty of stock out there. Seems a bit pricey at $1.50- not sure if that's another "supply chain" issue or it was always that way. Price is slow to come down in quantity. Makes no difference to a "one-off" project.If it's a one off, who cares about much of anything other than getting it to work? -- Rick C. --- Get 1,000 miles of free Supercharging --- Tesla referral code - https://ts.la/richard11209
