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Dirt cheap inverter/buffer with RDSon < 10 ohm?

Started by Klaus Kragelund September 1, 2017
Hi

I am using the 74AC14 for driving a medium power MOSFET

I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible

74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms

http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf

I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach

So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package

Cheers

Klaus 
On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund
<klauskvik@hotmail.com> wrote:

>Hi > >I am using the 74AC14 for driving a medium power MOSFET > >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > >Cheers > >Klaus
How about an HCT or ACT hex something, one section driving the other five in parallel? You've basically got that in the AC14. I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in parallel, insanely fast, 12 cents, but that needs CMOS level drive, not HCT. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On Saturday, September 2, 2017 at 1:02:43 AM UTC+2, John Larkin wrote:
> On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund > <klauskvik@hotmail.com> wrote: > > >Hi > > > >I am using the 74AC14 for driving a medium power MOSFET > > > >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > > >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > > >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > > >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > > >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > > >Cheers > > > >Klaus > > How about an HCT or ACT hex something, one section driving the other > five in parallel? You've basically got that in the AC14. >
I drive 3 FETs, so that would be one package per FET. I would like to drive them all from a single IC, 3 pcs is too expensive.
> I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in > parallel, insanely fast, 12 cents, but that needs CMOS level drive, > not HCT. >
That is a good one, similar to the other ones I found, equivalent resistance of about 17 ohms, but about 3 times to high I have looked into analog switches, which comes down in the numbers needed, but then the manufacturer knows well that he can ask for a higher price :-( Cheers Klaus
> > -- > > John Larkin Highland Technology, Inc > picosecond timing precision measurement > > jlarkin att highlandtechnology dott com > http://www.highlandtechnology.com
On Saturday, September 2, 2017 at 2:33:08 AM UTC-4, Klaus Kragelund wrote:
> On Saturday, September 2, 2017 at 1:02:43 AM UTC+2, John Larkin wrote: > > On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund > > <klauskvik@hotmail.com> wrote: > > > > >Hi > > > > > >I am using the 74AC14 for driving a medium power MOSFET > > > > > >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > > > > >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > > > > >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > > > > >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > > > > >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > > > > >Cheers > > > > > >Klaus > > > > How about an HCT or ACT hex something, one section driving the other > > five in parallel? You've basically got that in the AC14. > > > > I drive 3 FETs, so that would be one package per FET. I would like to drive them all from a single IC, 3 pcs is too expensive. > > > I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in > > parallel, insanely fast, 12 cents, but that needs CMOS level drive, > > not HCT. > > > > That is a good one, similar to the other ones I found, equivalent resistance of about 17 ohms, but about 3 times to high > > I have looked into analog switches, which comes down in the numbers needed, but then the manufacturer knows well that he can ask for a higher price :-(
But an analog switch can only drive in one direction, so you'd need two per MOSFET. Expensive. Paralleling two 'AC14 sections and driving both with a third 'AC14 section would get you two drivers per 'AC14 package. An octal buffer part (e.g. the 'AC240) would get you three drivers. But, in this service, do you really *want* three drivers talking to each other over a common bond wire to ground? Cheers, James Arthur
On Saturday, September 2, 2017 at 8:39:53 AM UTC-4, dagmarg...@yahoo.com wrote:
> On Saturday, September 2, 2017 at 2:33:08 AM UTC-4, Klaus Kragelund wrote: > > On Saturday, September 2, 2017 at 1:02:43 AM UTC+2, John Larkin wrote: > > > On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund > > > <klauskvik@hotmail.com> wrote: > > > > > > >Hi > > > > > > > >I am using the 74AC14 for driving a medium power MOSFET > > > > > > > >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > > > > > > >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > > > > > > >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > > > > > > >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > > > > > > >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > > > > > > >Cheers > > > > > > > >Klaus > > > > > > How about an HCT or ACT hex something, one section driving the other > > > five in parallel? You've basically got that in the AC14. > > > > > > > I drive 3 FETs, so that would be one package per FET. I would like to drive them all from a single IC, 3 pcs is too expensive. > > > > > I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in > > > parallel, insanely fast, 12 cents, but that needs CMOS level drive, > > > not HCT. > > > > > > > That is a good one, similar to the other ones I found, equivalent resistance of about 17 ohms, but about 3 times to high > > > > I have looked into analog switches, which comes down in the numbers needed, but then the manufacturer knows well that he can ask for a higher price :-( > > But an analog switch can only drive in one direction, so you'd need two > per MOSFET. Expensive. > > Paralleling two 'AC14 sections and driving both with a third 'AC14 section > would get you two drivers per 'AC14 package. > > An octal buffer part (e.g. the 'AC240) would get you three drivers. But, > in this service, do you really *want* three drivers talking to each other > over a common bond wire to ground?
Oh dear, an octal is one gate shy. Scratch that. But you could use an octal, make two drivers with six gates, and the last driver with one external buffer e.g., +5V | |/ ||-- ... .--------| ||<-. |\ | .---. |>. ||--+ >---| >O--+--| |---+----' | |/ '---' === Depends on what you're switching and how fast it needs to be. Cheers, James Arthur
On 9/1/2017 5:10 PM, Klaus Kragelund wrote:
> Hi > > I am using the 74AC14 for driving a medium power MOSFET > > I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > 74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > Cheers > > Klaus >
What is the part number of your medium power MOSFET?
On Saturday, September 2, 2017 at 2:39:53 PM UTC+2, dagmarg...@yahoo.com wrote:
> On Saturday, September 2, 2017 at 2:33:08 AM UTC-4, Klaus Kragelund wrote: > > On Saturday, September 2, 2017 at 1:02:43 AM UTC+2, John Larkin wrote: > > > On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund > > > <klauskvik@hotmail.com> wrote: > > > > > > >Hi > > > > > > > >I am using the 74AC14 for driving a medium power MOSFET > > > > > > > >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > > > > > > >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > > > > > > >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > > > > > > >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > > > > > > >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > > > > > > >Cheers > > > > > > > >Klaus > > > > > > How about an HCT or ACT hex something, one section driving the other > > > five in parallel? You've basically got that in the AC14. > > > > > > > I drive 3 FETs, so that would be one package per FET. I would like to drive them all from a single IC, 3 pcs is too expensive. > > > > > I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in > > > parallel, insanely fast, 12 cents, but that needs CMOS level drive, > > > not HCT. > > > > > > > That is a good one, similar to the other ones I found, equivalent resistance of about 17 ohms, but about 3 times to high > > > > I have looked into analog switches, which comes down in the numbers needed, but then the manufacturer knows well that he can ask for a higher price :-( > > But an analog switch can only drive in one direction, so you'd need two > per MOSFET. Expensive. >
Well, no, the double throw analog switch makes it easy: http://www.ti.com/lit/ds/symlink/sn74lvc1g3157.pdf
> Paralleling two 'AC14 sections and driving both with a third 'AC14 section > would get you two drivers per 'AC14 package. >
Yes, might be an option, but still more expensive that I would like
> An octal buffer part (e.g. the 'AC240) would get you three drivers. But, > in this service, do you really *want* three drivers talking to each other > over a common bond wire to ground? >
No problem with ground, but the 74AC240 is expensive Cheers Klaus
On Saturday, September 2, 2017 at 4:00:12 PM UTC+2, John S wrote:
> On 9/1/2017 5:10 PM, Klaus Kragelund wrote: > > Hi > > > > I am using the 74AC14 for driving a medium power MOSFET > > > > I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > > > 74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > > > http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > > > I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > > > So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > > > Cheers > > > > Klaus > > > > What is the part number of your medium power MOSFET?
https://www.diodes.com/assets/Datasheets/DMC4047LSD.pdf
On Saturday, September 2, 2017 at 2:51:36 PM UTC+2, dagmarg...@yahoo.com wrote:
> On Saturday, September 2, 2017 at 8:39:53 AM UTC-4, dagmarg...@yahoo.com wrote: > > On Saturday, September 2, 2017 at 2:33:08 AM UTC-4, Klaus Kragelund wrote: > > > On Saturday, September 2, 2017 at 1:02:43 AM UTC+2, John Larkin wrote: > > > > On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund > > > > <klauskvik@hotmail.com> wrote: > > > > > > > > >Hi > > > > > > > > > >I am using the 74AC14 for driving a medium power MOSFET > > > > > > > > > >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible > > > > > > > > > >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms > > > > > > > > > >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf > > > > > > > > > >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach > > > > > > > > > >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package > > > > > > > > > >Cheers > > > > > > > > > >Klaus > > > > > > > > How about an HCT or ACT hex something, one section driving the other > > > > five in parallel? You've basically got that in the AC14. > > > > > > > > > > I drive 3 FETs, so that would be one package per FET. I would like to drive them all from a single IC, 3 pcs is too expensive. > > > > > > > I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in > > > > parallel, insanely fast, 12 cents, but that needs CMOS level drive, > > > > not HCT. > > > > > > > > > > That is a good one, similar to the other ones I found, equivalent resistance of about 17 ohms, but about 3 times to high > > > > > > I have looked into analog switches, which comes down in the numbers needed, but then the manufacturer knows well that he can ask for a higher price :-( > > > > But an analog switch can only drive in one direction, so you'd need two > > per MOSFET. Expensive. > > > > Paralleling two 'AC14 sections and driving both with a third 'AC14 section > > would get you two drivers per 'AC14 package. > > > > An octal buffer part (e.g. the 'AC240) would get you three drivers. But, > > in this service, do you really *want* three drivers talking to each other > > over a common bond wire to ground? > > Oh dear, an octal is one gate shy. Scratch that. But you could use an > octal, make two drivers with six gates, and the last driver with one > external buffer e.g.,
Yes, a picogate could be external for the one that is needed for driving the other 2 gates
> > +5V > | > |/ ||-- ... > .--------| ||<-. > |\ | .---. |>. ||--+ > >---| >O--+--| |---+----' | > |/ '---' === > > Depends on what you're switching and how fast it needs to be.
That is pretty close to be the same as the current optimum circuit I am working on :-)
>
Cheers Klaus
On Fri, 1 Sep 2017 23:33:01 -0700 (PDT), Klaus Kragelund
<klauskvik@hotmail.com> wrote:

>On Saturday, September 2, 2017 at 1:02:43 AM UTC+2, John Larkin wrote: >> On Fri, 1 Sep 2017 15:10:18 -0700 (PDT), Klaus Kragelund >> <klauskvik@hotmail.com> wrote: >> >> >Hi >> > >> >I am using the 74AC14 for driving a medium power MOSFET >> > >> >I need it dirt cheap, so no external small signal MOSFET to help to drive the power MOSFET possible >> > >> >74AC14, which is very cheap, has 24mA drive, ca. 0.65V, which translates to euquivalent RDSon to about 26 ohms >> > >> >http://www.mouser.com/ds/2/149/74ACT14-1006522.pdf >> > >> >I could parallel 2 of them, but since my input is slowly moving, that would be an questionable approach >> > >> >So, anyone got partnumber on a about 10 ohm or better logic level IC, dirt cheap, preferable 2-3 or more parts in a package >> > >> >Cheers >> > >> >Klaus >> >> How about an HCT or ACT hex something, one section driving the other >> five in parallel? You've basically got that in the AC14. >> > >I drive 3 FETs, so that would be one package per FET. I would like to drive them all from a single IC, 3 pcs is too expensive. > >> I like ON SEMI NL37WZ16US, at abs max Vcc, three sections in >> parallel, insanely fast, 12 cents, but that needs CMOS level drive, >> not HCT. >> > >That is a good one, similar to the other ones I found, equivalent resistance of about 17 ohms, but about 3 times to high
You must be driving giant fets. The NL37WZ16 rise time, unloaded, is about 700 ps. Driving the just-right-size fet, you can switch 50 volts at 1 amp in about a nanosecond. Of course, our products are lowish quantity, and parts cost doesn't usually matter much. I sometimes use two or even three of the tiny triples in parallel (like, 9 gates!) to drive a mosfet. "Anything worth doing is worth overdoing." - Meat Loaf
> >I have looked into analog switches, which comes down in the numbers needed, but then the manufacturer knows well that he can ask for a higher price :-(
The USB switches are fairly cheap and just a few ohms. -- John Larkin Highland Technology, Inc lunatic fringe electronics