IR is insane
in [Design]
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From: John Larkin on 18 Mar 2010 20:48 On Thu, 18 Mar 2010 19:37:49 -0500, John Fields <jfields(a)austininstruments.com> wrote: >On Thu, 18 Mar 2010 17:19:12 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Thu, 18 Mar 2010 18:02:27 -0500, Damon Hill >><damon16ONE(a)comcast.not> wrote: >> >>>John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>>news:cpb5q5p2013r34ainnmcrdfjml4ifvp03g(a)4ax.com: >>> >>>> Just got a short-form IR mosfet thing in the mail. >>>> >>>> They have a PQFN 5x6 mm package they rate at 104 amps. And a D2PAK >>>> rated for 340 amps. >>> >>>Hmm. Define 'continuous'. (a >very< short pulse rating I'd believe) >>> >> >>The flyer doesn't mention pulsing. The D2PAK datasheet pulsed current >>rating is 1080 amps. >> >>http://www.irf.com/product-info/datasheets/data/irfs3006pbf.pdf >> >>The flyer claims 340 amps. The datasheet says 270 amps but "package >>limited" to 195. I don't believe any of them. >> >>The datasheet also claims 375 watts power dissipation... in a D2PAK! > >--- >Maybe they're talking power dissipation in the load with the switch >saturated, like TI used to in the late 50's and early 60's. 60 volts * 340 amps = 20,400 watts. So that ain't it. > >In any case, if you don't believe it why don't you build something to >prove your point instead of just flapping your gums, as usual? > >JF Are you willing to run a D2PAK fet at 375 watts power dissipation? Or 195 amps continuous drain current? John
From: John Fields on 18 Mar 2010 21:01 On Thu, 18 Mar 2010 17:48:50 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 18 Mar 2010 19:37:49 -0500, John Fields ><jfields(a)austininstruments.com> wrote: > >>On Thu, 18 Mar 2010 17:19:12 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Thu, 18 Mar 2010 18:02:27 -0500, Damon Hill >>><damon16ONE(a)comcast.not> wrote: >>> >>>>John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>>>news:cpb5q5p2013r34ainnmcrdfjml4ifvp03g(a)4ax.com: >>>> >>>>> Just got a short-form IR mosfet thing in the mail. >>>>> >>>>> They have a PQFN 5x6 mm package they rate at 104 amps. And a D2PAK >>>>> rated for 340 amps. >>>> >>>>Hmm. Define 'continuous'. (a >very< short pulse rating I'd believe) >>>> >>> >>>The flyer doesn't mention pulsing. The D2PAK datasheet pulsed current >>>rating is 1080 amps. >>> >>>http://www.irf.com/product-info/datasheets/data/irfs3006pbf.pdf >>> >>>The flyer claims 340 amps. The datasheet says 270 amps but "package >>>limited" to 195. I don't believe any of them. >>> >>>The datasheet also claims 375 watts power dissipation... in a D2PAK! >> >>--- >>Maybe they're talking power dissipation in the load with the switch >>saturated, like TI used to in the late 50's and early 60's. > >60 volts * 340 amps = 20,400 watts. So that ain't it. > >> >>In any case, if you don't believe it why don't you build something to >>prove your point instead of just flapping your gums, as usual? >> >>JF > >Are you willing to run a D2PAK fet at 375 watts power dissipation? Or >195 amps continuous drain current? --- It's not on me, John. You're the one doing all the bitching and moaning, so it's up to you to prove your point in the real world. It's not like you're financially strapped and can't afford to do it, so why don't you just put up or shut up? JF
From: MooseFET on 18 Mar 2010 21:46 On Mar 18, 3:58 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > Just got a short-form IR mosfet thing in the mail. > > They have a PQFN 5x6 mm package they rate at 104 amps. And a D2PAK > rated for 340 amps. Maybe there was a simple typo in the information. It may be a PQFN 5x6 meter package. > > John
From: a7yvm109gf5d1 on 18 Mar 2010 21:52 On Mar 18, 7:48 pm, John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > On Thu, 18 Mar 2010 19:37:49 -0500, John Fields > > > > <jfie...(a)austininstruments.com> wrote: > >On Thu, 18 Mar 2010 17:19:12 -0700, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >>On Thu, 18 Mar 2010 18:02:27 -0500, Damon Hill > >><damon16...(a)comcast.not> wrote: > > >>>John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in > >>>news:cpb5q5p2013r34ainnmcrdfjml4ifvp03g(a)4ax.com: > > >>>> Just got a short-form IR mosfet thing in the mail. > > >>>> They have a PQFN 5x6 mm package they rate at 104 amps. And a D2PAK > >>>> rated for 340 amps. > > >>>Hmm. Define 'continuous'. (a >very< short pulse rating I'd believe) > > >>The flyer doesn't mention pulsing. The D2PAK datasheet pulsed current > >>rating is 1080 amps. > > >>http://www.irf.com/product-info/datasheets/data/irfs3006pbf.pdf > > >>The flyer claims 340 amps. The datasheet says 270 amps but "package > >>limited" to 195. I don't believe any of them. > > >>The datasheet also claims 375 watts power dissipation... in a D2PAK! > > >--- > >Maybe they're talking power dissipation in the load with the switch > >saturated, like TI used to in the late 50's and early 60's. > > 60 volts * 340 amps = 20,400 watts. So that ain't it. > > > > >In any case, if you don't believe it why don't you build something to > >prove your point instead of just flapping your gums, as usual? > > >JF > > Are you willing to run a D2PAK fet at 375 watts power dissipation? Or > 195 amps continuous drain current? > > John Wiki claims "hundreds of amps" for the secondary of the transformer inside those Weller soldering guns. So you got an easy source of amps there. Seems to me if the constriction in the copper bar that serves as the iron element gets hot, those tiny pins should get hot too?
From: John Larkin on 18 Mar 2010 23:26
On Thu, 18 Mar 2010 20:01:31 -0500, John Fields <jfields(a)austininstruments.com> wrote: >On Thu, 18 Mar 2010 17:48:50 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Thu, 18 Mar 2010 19:37:49 -0500, John Fields >><jfields(a)austininstruments.com> wrote: >> >>>On Thu, 18 Mar 2010 17:19:12 -0700, John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Thu, 18 Mar 2010 18:02:27 -0500, Damon Hill >>>><damon16ONE(a)comcast.not> wrote: >>>> >>>>>John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in >>>>>news:cpb5q5p2013r34ainnmcrdfjml4ifvp03g(a)4ax.com: >>>>> >>>>>> Just got a short-form IR mosfet thing in the mail. >>>>>> >>>>>> They have a PQFN 5x6 mm package they rate at 104 amps. And a D2PAK >>>>>> rated for 340 amps. >>>>> >>>>>Hmm. Define 'continuous'. (a >very< short pulse rating I'd believe) >>>>> >>>> >>>>The flyer doesn't mention pulsing. The D2PAK datasheet pulsed current >>>>rating is 1080 amps. >>>> >>>>http://www.irf.com/product-info/datasheets/data/irfs3006pbf.pdf >>>> >>>>The flyer claims 340 amps. The datasheet says 270 amps but "package >>>>limited" to 195. I don't believe any of them. >>>> >>>>The datasheet also claims 375 watts power dissipation... in a D2PAK! >>> >>>--- >>>Maybe they're talking power dissipation in the load with the switch >>>saturated, like TI used to in the late 50's and early 60's. >> >>60 volts * 340 amps = 20,400 watts. So that ain't it. >> >>> >>>In any case, if you don't believe it why don't you build something to >>>prove your point instead of just flapping your gums, as usual? >>> >>>JF >> >>Are you willing to run a D2PAK fet at 375 watts power dissipation? Or >>195 amps continuous drain current? > >--- >It's not on me, John. > >You're the one doing all the bitching and moaning, so it's up to you to >prove your point in the real world. > >It's not like you're financially strapped and can't afford to do it, so >why don't you just put up or shut up? > >JF Heck, I don't need to experiment to show that 340 amps will blow a dpak to hell at speed. I'm an engineer, and can figure that out in advance. And all those flames and smoke and sparks would be downright distasteful. John |