TO220--thin leads--high current--How?
in [Design]
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From: John Larkin on 5 May 2010 10:09 On Tue, 04 May 2010 21:48:43 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Tue, 04 May 2010 07:05:08 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Mon, 03 May 2010 23:06:40 -0700, >>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >> >>>On Sun, 2 May 2010 14:12:13 -0700 (PDT), "oparr(a)hotmail.com" >>><oparr(a)hotmail.com> wrote: >>> >>>>> 429?!!! The most ludicrous IR claim I've seen for a D2PAK was 340. >>>> >>>>The spec states that 429A is; >>>> >>>>"Calculated continuous current based on maximum allowable junction >>>>temperature. Package limitation current is 160A." >>>> >>>>The only thing that makes sense is the packaged limited current IMO. >>>>This D2PAK has 6 source leads and the entire tab is the drain lead. >>>> >>>>On May 2, 3:46�pm, John Larkin wrote: >>>>> >>> >>>Again an infinite heatsink driven by copious amounts of LN2. >> >>Gp they use LN2? The appnote cited here said "nucleated boiling >>liquid." >> >>John > >Are you proposing that LN2 cannot boil in the normal (nucleate) way? No. I was just wondering which liquid IR uses to generate their absurd dishonest ratings. John
From: Grant on 5 May 2010 20:12 On Wed, 05 May 2010 07:09:09 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Tue, 04 May 2010 21:48:43 -0700, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Tue, 04 May 2010 07:05:08 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Mon, 03 May 2010 23:06:40 -0700, >>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>> >>>>On Sun, 2 May 2010 14:12:13 -0700 (PDT), "oparr(a)hotmail.com" >>>><oparr(a)hotmail.com> wrote: >>>> >>>>>> 429?!!! The most ludicrous IR claim I've seen for a D2PAK was 340. >>>>> >>>>>The spec states that 429A is; >>>>> >>>>>"Calculated continuous current based on maximum allowable junction >>>>>temperature. Package limitation current is 160A." >>>>> >>>>>The only thing that makes sense is the packaged limited current IMO. >>>>>This D2PAK has 6 source leads and the entire tab is the drain lead. >>>>> >>>>>On May 2, 3:46 pm, John Larkin wrote: >>>>>> >>>> >>>>Again an infinite heatsink driven by copious amounts of LN2. >>> >>>Gp they use LN2? The appnote cited here said "nucleated boiling >>>liquid." >>> >>>John >> >>Are you proposing that LN2 cannot boil in the normal (nucleate) way? > >No. I was just wondering which liquid IR uses to generate their absurd >dishonest ratings. Simulated liquid? :) I worked for a company over 30 years ago, that took IR to court regarding over-rated SCRs that failed too often in the field. This IR attitude seems well established. Grant. -- http://bugs.id.au/
From: John Larkin on 5 May 2010 21:01 On Thu, 06 May 2010 10:12:17 +1000, Grant <omg(a)grrr.id.au> wrote: >On Wed, 05 May 2010 07:09:09 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Tue, 04 May 2010 21:48:43 -0700, >>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >> >>>On Tue, 04 May 2010 07:05:08 -0700, John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Mon, 03 May 2010 23:06:40 -0700, >>>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>>> >>>>>On Sun, 2 May 2010 14:12:13 -0700 (PDT), "oparr(a)hotmail.com" >>>>><oparr(a)hotmail.com> wrote: >>>>> >>>>>>> 429?!!! The most ludicrous IR claim I've seen for a D2PAK was 340. >>>>>> >>>>>>The spec states that 429A is; >>>>>> >>>>>>"Calculated continuous current based on maximum allowable junction >>>>>>temperature. Package limitation current is 160A." >>>>>> >>>>>>The only thing that makes sense is the packaged limited current IMO. >>>>>>This D2PAK has 6 source leads and the entire tab is the drain lead. >>>>>> >>>>>>On May 2, 3:46�pm, John Larkin wrote: >>>>>>> >>>>> >>>>>Again an infinite heatsink driven by copious amounts of LN2. >>>> >>>>Gp they use LN2? The appnote cited here said "nucleated boiling >>>>liquid." >>>> >>>>John >>> >>>Are you proposing that LN2 cannot boil in the normal (nucleate) way? >> >>No. I was just wondering which liquid IR uses to generate their absurd >>dishonest ratings. > >Simulated liquid? :) > >I worked for a company over 30 years ago, that took IR to court >regarding over-rated SCRs that failed too often in the field. > >This IR attitude seems well established. > >Grant. www.irf.com/technical-info/appnotes/an-1140.pdf Their "ultimate current" ratings are apparently done in an "inert nucleated boiling liquid" at 23C, which doesn't sound much like LN2 to me. And they seem to be testing DPAKs on a solid aluminum "pc board." John
From: krw on 5 May 2010 21:31 On Wed, 05 May 2010 18:01:08 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 06 May 2010 10:12:17 +1000, Grant <omg(a)grrr.id.au> wrote: > >>On Wed, 05 May 2010 07:09:09 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Tue, 04 May 2010 21:48:43 -0700, >>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>> >>>>On Tue, 04 May 2010 07:05:08 -0700, John Larkin >>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>>On Mon, 03 May 2010 23:06:40 -0700, >>>>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>>>> >>>>>>On Sun, 2 May 2010 14:12:13 -0700 (PDT), "oparr(a)hotmail.com" >>>>>><oparr(a)hotmail.com> wrote: >>>>>> >>>>>>>> 429?!!! The most ludicrous IR claim I've seen for a D2PAK was 340. >>>>>>> >>>>>>>The spec states that 429A is; >>>>>>> >>>>>>>"Calculated continuous current based on maximum allowable junction >>>>>>>temperature. Package limitation current is 160A." >>>>>>> >>>>>>>The only thing that makes sense is the packaged limited current IMO. >>>>>>>This D2PAK has 6 source leads and the entire tab is the drain lead. >>>>>>> >>>>>>>On May 2, 3:46�pm, John Larkin wrote: >>>>>>>> >>>>>> >>>>>>Again an infinite heatsink driven by copious amounts of LN2. >>>>> >>>>>Gp they use LN2? The appnote cited here said "nucleated boiling >>>>>liquid." >>>>> >>>>>John >>>> >>>>Are you proposing that LN2 cannot boil in the normal (nucleate) way? >>> >>>No. I was just wondering which liquid IR uses to generate their absurd >>>dishonest ratings. >> >>Simulated liquid? :) >> >>I worked for a company over 30 years ago, that took IR to court >>regarding over-rated SCRs that failed too often in the field. >> >>This IR attitude seems well established. >> >>Grant. > > >www.irf.com/technical-info/appnotes/an-1140.pdf > >Their "ultimate current" ratings are apparently done in an "inert >nucleated boiling liquid" at 23C, which doesn't sound much like LN2 to >me. It could be, with the appropriate resistor inbetween. Kinda tough to stabilize the mess, but it only has to work long enough to make the measurement. >And they seem to be testing DPAKs on a solid aluminum "pc board." Speaking of which, does anyone have information on the JEDEC JEXD51-7 standards for high and low "effective thermal conductivity test boards"? Unfortunately we're not members and aren't likely to be.
From: John Larkin on 5 May 2010 23:10
On Wed, 05 May 2010 20:31:22 -0500, "krw(a)att.bizzzzzzzzzzzz" <krw(a)att.bizzzzzzzzzzzz> wrote: >On Wed, 05 May 2010 18:01:08 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Thu, 06 May 2010 10:12:17 +1000, Grant <omg(a)grrr.id.au> wrote: >> >>>On Wed, 05 May 2010 07:09:09 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Tue, 04 May 2010 21:48:43 -0700, >>>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>>> >>>>>On Tue, 04 May 2010 07:05:08 -0700, John Larkin >>>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>>On Mon, 03 May 2010 23:06:40 -0700, >>>>>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>>>>> >>>>>>>On Sun, 2 May 2010 14:12:13 -0700 (PDT), "oparr(a)hotmail.com" >>>>>>><oparr(a)hotmail.com> wrote: >>>>>>> >>>>>>>>> 429?!!! The most ludicrous IR claim I've seen for a D2PAK was 340. >>>>>>>> >>>>>>>>The spec states that 429A is; >>>>>>>> >>>>>>>>"Calculated continuous current based on maximum allowable junction >>>>>>>>temperature. Package limitation current is 160A." >>>>>>>> >>>>>>>>The only thing that makes sense is the packaged limited current IMO. >>>>>>>>This D2PAK has 6 source leads and the entire tab is the drain lead. >>>>>>>> >>>>>>>>On May 2, 3:46�pm, John Larkin wrote: >>>>>>>>> >>>>>>> >>>>>>>Again an infinite heatsink driven by copious amounts of LN2. >>>>>> >>>>>>Gp they use LN2? The appnote cited here said "nucleated boiling >>>>>>liquid." >>>>>> >>>>>>John >>>>> >>>>>Are you proposing that LN2 cannot boil in the normal (nucleate) way? >>>> >>>>No. I was just wondering which liquid IR uses to generate their absurd >>>>dishonest ratings. >>> >>>Simulated liquid? :) >>> >>>I worked for a company over 30 years ago, that took IR to court >>>regarding over-rated SCRs that failed too often in the field. >>> >>>This IR attitude seems well established. >>> >>>Grant. >> >> >>www.irf.com/technical-info/appnotes/an-1140.pdf >> >>Their "ultimate current" ratings are apparently done in an "inert >>nucleated boiling liquid" at 23C, which doesn't sound much like LN2 to >>me. > >It could be, with the appropriate resistor inbetween. Kinda tough to >stabilize the mess, but it only has to work long enough to make the >measurement. LN2 is pretty thin stuff, namely low specific heat. Water is fabulous. Maybe they used distilled water under enough vacuum to boil at 23C. Wouldn't put it past them. John |