On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:>On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin ><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>>On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>><jlarkin@highlandtechnology.com> wrote: >>>> >>>>>On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>> >>>>>>Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>variance between them, and some down-right non-physical behavior. >>>>>> >>>>>>Has anyone found a better 2N7000 model since then? >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>>The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>which is why some of our products specify a specific manufacturer for >>>>>these parts. >>>>> >>>>>What non-physical behavior are you seeing? >>>> >>>>All but the Supertex model failed to model ANY behavior below >>>>threshold, and the Supertex model had discontinuities in the ID/VDS >>>>curve blending... guaranteed to cause simulator convergence issues. >>>> >>>> ...Jim Thompson >>> >>>I forgot to reference my old post (4/6/2005)... >>> >>>http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>> >>>Second page tells it all. >>> >>> ...Jim Thompson >> >>If you're actually designing boards with 2N7000s, any of those curves is about >>as good as any other. Real-life parts will be all over the map. > >You didn't notice the discontinuities? > > ...Jim ThompsonSure, but they are down in the "noise" of part-part differences. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
2N7000 Spice Model
Started by ●June 17, 2014
Reply by ●June 18, 20142014-06-18
Reply by ●June 18, 20142014-06-18
>"guaranteed to cause simulator convergence issues..."So let me get this straight. If any little thing happens this is smoked, right ?
Reply by ●June 18, 20142014-06-18
On Tue, 17 Jun 2014 21:57:08 -0700, John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:>On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin >><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>>On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>> >>>>>On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>>><jlarkin@highlandtechnology.com> wrote: >>>>> >>>>>>On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>> >>>>>>>Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>>variance between them, and some down-right non-physical behavior. >>>>>>> >>>>>>>Has anyone found a better 2N7000 model since then? >>>>>>> >>>>>>> ...Jim Thompson >>>>>> >>>>>>The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>>which is why some of our products specify a specific manufacturer for >>>>>>these parts. >>>>>> >>>>>>What non-physical behavior are you seeing? >>>>> >>>>>All but the Supertex model failed to model ANY behavior below >>>>>threshold, and the Supertex model had discontinuities in the ID/VDS >>>>>curve blending... guaranteed to cause simulator convergence issues. >>>>> >>>>> ...Jim Thompson >>>> >>>>I forgot to reference my old post (4/6/2005)... >>>> >>>>http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>>> >>>>Second page tells it all. >>>> >>>> ...Jim Thompson >>> >>>If you're actually designing boards with 2N7000s, any of those curves is about >>>as good as any other. Real-life parts will be all over the map. >> >>You didn't notice the discontinuities? >> >> ...Jim Thompson > >Sure, but they are down in the "noise" of part-part differences.Refer back in the history of this group, and Win Hill's concern about operation in the subthreshold region. Use as a low noise amplifier is quite different from just using the device as a switch. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 18, 20142014-06-18
On Wed, 18 Jun 2014 07:40:52 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:>On Tue, 17 Jun 2014 21:57:08 -0700, John Larkin ><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin >>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>> >>>>>On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>> >>>>>>On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>>>><jlarkin@highlandtechnology.com> wrote: >>>>>> >>>>>>>On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>> >>>>>>>>Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>>>variance between them, and some down-right non-physical behavior. >>>>>>>> >>>>>>>>Has anyone found a better 2N7000 model since then? >>>>>>>> >>>>>>>> ...Jim Thompson >>>>>>> >>>>>>>The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>>>which is why some of our products specify a specific manufacturer for >>>>>>>these parts. >>>>>>> >>>>>>>What non-physical behavior are you seeing? >>>>>> >>>>>>All but the Supertex model failed to model ANY behavior below >>>>>>threshold, and the Supertex model had discontinuities in the ID/VDS >>>>>>curve blending... guaranteed to cause simulator convergence issues. >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>>I forgot to reference my old post (4/6/2005)... >>>>> >>>>>http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>>>> >>>>>Second page tells it all. >>>>> >>>>> ...Jim Thompson >>>> >>>>If you're actually designing boards with 2N7000s, any of those curves is about >>>>as good as any other. Real-life parts will be all over the map. >>> >>>You didn't notice the discontinuities? >>> >>> ...Jim Thompson >> >>Sure, but they are down in the "noise" of part-part differences. > >Refer back in the history of this group, and Win Hill's concern about >operation in the subthreshold region. Use as a low noise amplifier is >quite different from just using the device as a switch. > > ...Jim ThompsonHere's a graph that I found in our PDATA folder for the 2N7000. I don't know where it came from, possibly from Win. https://dl.dropboxusercontent.com/u/53724080/Parts/Fets/2n7000_off_leakage.pdf (people should sign and date everything that they create) What does "subthreshold" mean anyhow? It seeme to me that specified gate thresholds are based on arbitrary drain currents. That curve above has no threshold. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
Reply by ●June 18, 20142014-06-18
On Tue, 17 Jun 2014 18:21:48 -0700, Robert Baer <robertbaer@localnet.com> wrote:>Jim Thompson wrote: >> On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>> On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>> <jlarkin@highlandtechnology.com> wrote: >>> >>>> On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>> >>>>> Last time I tested several 2N7000 Spice models (2005), there was huge >>>>> variance between them, and some down-right non-physical behavior. >>>>> >>>>> Has anyone found a better 2N7000 model since then? >>>>> >>>>> ...Jim Thompson >>>> >>>> The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>> which is why some of our products specify a specific manufacturer for >>>> these parts. >>>> >>>> What non-physical behavior are you seeing? >>> >>> All but the Supertex model failed to model ANY behavior below >>> threshold, and the Supertex model had discontinuities in the ID/VDS >>> curve blending... guaranteed to cause simulator convergence issues. >>> >>> ...Jim Thompson >> >> I forgot to reference my old post (4/6/2005)... >> >> http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >> >> Second page tells it all. >> >> ...Jim Thompson > Attached is an old Infineon lib of FETs, etc that may be of use.No model level higher then Level=3... that is, early school-boy text-book complexity. The problem is that it is quite rare to see discrete MOS devices modeled properly as BSIM3v3. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 18, 20142014-06-18
On Wed, 18 Jun 2014 07:50:07 -0700, John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:>On Wed, 18 Jun 2014 07:40:52 -0700, Jim Thompson ><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Tue, 17 Jun 2014 21:57:08 -0700, John Larkin >><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson >>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>>On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin >>>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>>On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>> >>>>>>On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>> >>>>>>>On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>>>>><jlarkin@highlandtechnology.com> wrote: >>>>>>> >>>>>>>>On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>>>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>>> >>>>>>>>>Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>>>>variance between them, and some down-right non-physical behavior. >>>>>>>>> >>>>>>>>>Has anyone found a better 2N7000 model since then? >>>>>>>>> >>>>>>>>> ...Jim Thompson >>>>>>>> >>>>>>>>The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>>>>which is why some of our products specify a specific manufacturer for >>>>>>>>these parts. >>>>>>>> >>>>>>>>What non-physical behavior are you seeing? >>>>>>> >>>>>>>All but the Supertex model failed to model ANY behavior below >>>>>>>threshold, and the Supertex model had discontinuities in the ID/VDS >>>>>>>curve blending... guaranteed to cause simulator convergence issues. >>>>>>> >>>>>>> ...Jim Thompson >>>>>> >>>>>>I forgot to reference my old post (4/6/2005)... >>>>>> >>>>>>http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>>>>> >>>>>>Second page tells it all. >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>>If you're actually designing boards with 2N7000s, any of those curves is about >>>>>as good as any other. Real-life parts will be all over the map. >>>> >>>>You didn't notice the discontinuities? >>>> >>>> ...Jim Thompson >>> >>>Sure, but they are down in the "noise" of part-part differences. >> >>Refer back in the history of this group, and Win Hill's concern about >>operation in the subthreshold region. Use as a low noise amplifier is >>quite different from just using the device as a switch. >> >> ...Jim Thompson > >Here's a graph that I found in our PDATA folder for the 2N7000. I don't know >where it came from, possibly from Win. > >https://dl.dropboxusercontent.com/u/53724080/Parts/Fets/2n7000_off_leakage.pdf > >(people should sign and date everything that they create) > >What does "subthreshold" mean anyhow? It seeme to me that specified gate >thresholds are based on arbitrary drain currents. That curve above has no >threshold.That's not "leakage", it's the natural square-law behavior of MOS devices below "threshold"... sometimes used to make faux bandgaps with MOS ;-) I suspect Joerg regularly works down in this region. I recently participated in the design of a medical device (chip) where _everything_ operated subthreshold... the oscillators I mentioned before... 1kHz at 6nA, 1MHz at 1.2uA The definition of "threshold" is a vague. I have these papers that I can share, if any are interested... ...\ModelingIssues\ThresholdModeling_SalcedoEtAl.pdf ...\MOS-GateCharge\WinHill_subthreshold_mosfet_model.pdf (graphs) ...\MOS-GateCharge\Win Hill Data\2n7000_data_graphs.xls (data) ...\SubthresholdEffects\CurrentMirror_Novel_SubthresholdRegion.pdf ...\SubthresholdEffects\ExploitingSubthresholdMOSFET_Behavior.pdf ...\SubthresholdEffects\ReferencesFromSubthreshold MOSFETs.pdf ...\SubthresholdEffects\SubthresholdDeviceModeling.pdf ...\SubthresholdEffects\SubthresholdMOSforUltra-LowPower.pdf ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 18, 20142014-06-18
On 06/18/2014 10:50 AM, John Larkin wrote:> On Wed, 18 Jun 2014 07:40:52 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >> On Tue, 17 Jun 2014 21:57:08 -0700, John Larkin >> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >> >>> On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson >>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>> On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin >>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>> On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>> >>>>>> On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>> >>>>>>> On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>>>>> <jlarkin@highlandtechnology.com> wrote: >>>>>>> >>>>>>>> On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>>> >>>>>>>>> Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>>>> variance between them, and some down-right non-physical behavior. >>>>>>>>> >>>>>>>>> Has anyone found a better 2N7000 model since then? >>>>>>>>> >>>>>>>>> ...Jim Thompson >>>>>>>> >>>>>>>> The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>>>> which is why some of our products specify a specific manufacturer for >>>>>>>> these parts. >>>>>>>> >>>>>>>> What non-physical behavior are you seeing? >>>>>>> >>>>>>> All but the Supertex model failed to model ANY behavior below >>>>>>> threshold, and the Supertex model had discontinuities in the ID/VDS >>>>>>> curve blending... guaranteed to cause simulator convergence issues. >>>>>>> >>>>>>> ...Jim Thompson >>>>>> >>>>>> I forgot to reference my old post (4/6/2005)... >>>>>> >>>>>> http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>>>>> >>>>>> Second page tells it all. >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>> If you're actually designing boards with 2N7000s, any of those curves is about >>>>> as good as any other. Real-life parts will be all over the map. >>>> >>>> You didn't notice the discontinuities? >>>> >>>> ...Jim Thompson >>> >>> Sure, but they are down in the "noise" of part-part differences. >> >> Refer back in the history of this group, and Win Hill's concern about >> operation in the subthreshold region. Use as a low noise amplifier is >> quite different from just using the device as a switch. >> >> ...Jim Thompson > > Here's a graph that I found in our PDATA folder for the 2N7000. I don't know > where it came from, possibly from Win. > > https://dl.dropboxusercontent.com/u/53724080/Parts/Fets/2n7000_off_leakage.pdf > > (people should sign and date everything that they create) > > What does "subthreshold" mean anyhow? It seeme to me that specified gate > thresholds are based on arbitrary drain currents. That curve above has no > threshold.Very pretty. What was V_GS? Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Reply by ●June 18, 20142014-06-18
On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin wrote:> On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson > <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: > >>On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>>On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>><jlarkin@highlandtechnology.com> wrote: >>> >>>>On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>><To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>> >>>>>Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>variance between them, and some down-right non-physical behavior. >>>>> >>>>>Has anyone found a better 2N7000 model since then? >>>>> >>>>> ...Jim Thompson >>>> >>>>The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>which is why some of our products specify a specific manufacturer for >>>>these parts. >>>> >>>>What non-physical behavior are you seeing? >>> >>>All but the Supertex model failed to model ANY behavior below >>>threshold, and the Supertex model had discontinuities in the ID/VDS >>>curve blending... guaranteed to cause simulator convergence issues. >>> >>> ...Jim Thompson >> >>I forgot to reference my old post (4/6/2005)... >> >>http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >> >>Second page tells it all. >> >> ...Jim Thompson > > If you're actually designing boards with 2N7000s, any of those curves is > about as good as any other. Real-life parts will be all over the map.Not if the board function depends on sub-threshold behavior! -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Reply by ●June 18, 20142014-06-18
On Wed, 18 Jun 2014 12:40:26 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 06/18/2014 10:50 AM, John Larkin wrote: >> On Wed, 18 Jun 2014 07:40:52 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >> >>> On Tue, 17 Jun 2014 21:57:08 -0700, John Larkin >>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>> >>>> On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson >>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>> >>>>> On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin >>>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>> On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>> >>>>>>> On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>> >>>>>>>> On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>>>>>> <jlarkin@highlandtechnology.com> wrote: >>>>>>>> >>>>>>>>> On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>>>> >>>>>>>>>> Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>>>>> variance between them, and some down-right non-physical behavior. >>>>>>>>>> >>>>>>>>>> Has anyone found a better 2N7000 model since then? >>>>>>>>>> >>>>>>>>>> ...Jim Thompson >>>>>>>>> >>>>>>>>> The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>>>>> which is why some of our products specify a specific manufacturer for >>>>>>>>> these parts. >>>>>>>>> >>>>>>>>> What non-physical behavior are you seeing? >>>>>>>> >>>>>>>> All but the Supertex model failed to model ANY behavior below >>>>>>>> threshold, and the Supertex model had discontinuities in the ID/VDS >>>>>>>> curve blending... guaranteed to cause simulator convergence issues. >>>>>>>> >>>>>>>> ...Jim Thompson >>>>>>> >>>>>>> I forgot to reference my old post (4/6/2005)... >>>>>>> >>>>>>> http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>>>>>> >>>>>>> Second page tells it all. >>>>>>> >>>>>>> ...Jim Thompson >>>>>> >>>>>> If you're actually designing boards with 2N7000s, any of those curves is about >>>>>> as good as any other. Real-life parts will be all over the map. >>>>> >>>>> You didn't notice the discontinuities? >>>>> >>>>> ...Jim Thompson >>>> >>>> Sure, but they are down in the "noise" of part-part differences. >>> >>> Refer back in the history of this group, and Win Hill's concern about >>> operation in the subthreshold region. Use as a low noise amplifier is >>> quite different from just using the device as a switch. >>> >>> ...Jim Thompson >> >> Here's a graph that I found in our PDATA folder for the 2N7000. I don't know >> where it came from, possibly from Win. >> >> https://dl.dropboxusercontent.com/u/53724080/Parts/Fets/2n7000_off_leakage.pdf >> >> (people should sign and date everything that they create) >> >> What does "subthreshold" mean anyhow? It seeme to me that specified gate >> thresholds are based on arbitrary drain currents. That curve above has no >> threshold. > >Very pretty. What was V_GS? > >Cheers > >Phil HobbsDo you mean Vds? I don't know. -- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●June 18, 20142014-06-18
On 6/18/2014 5:06 PM, John Larkin wrote:> On Wed, 18 Jun 2014 12:40:26 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 06/18/2014 10:50 AM, John Larkin wrote: >>> On Wed, 18 Jun 2014 07:40:52 -0700, Jim Thompson >>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>> >>>> On Tue, 17 Jun 2014 21:57:08 -0700, John Larkin >>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>> On Tue, 17 Jun 2014 21:35:21 -0700, Jim Thompson >>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>> >>>>>> On Tue, 17 Jun 2014 19:44:42 -0700, John Larkin >>>>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: >>>>>> >>>>>>> On Tue, 17 Jun 2014 14:23:41 -0700, Jim Thompson >>>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>> >>>>>>>> On Tue, 17 Jun 2014 14:15:32 -0700, Jim Thompson >>>>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>>> >>>>>>>>> On Tue, 17 Jun 2014 12:02:40 -0700, John Larkin >>>>>>>>> <jlarkin@highlandtechnology.com> wrote: >>>>>>>>> >>>>>>>>>> On Tue, 17 Jun 2014 09:38:18 -0700, Jim Thompson >>>>>>>>>> <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote: >>>>>>>>>> >>>>>>>>>>> Last time I tested several 2N7000 Spice models (2005), there was huge >>>>>>>>>>> variance between them, and some down-right non-physical behavior. >>>>>>>>>>> >>>>>>>>>>> Has anyone found a better 2N7000 model since then? >>>>>>>>>>> >>>>>>>>>>> ...Jim Thompson >>>>>>>>>> >>>>>>>>>> The 2N7000/2N7002 parts themselves vary a lot between manufacturers, >>>>>>>>>> which is why some of our products specify a specific manufacturer for >>>>>>>>>> these parts. >>>>>>>>>> >>>>>>>>>> What non-physical behavior are you seeing? >>>>>>>>> >>>>>>>>> All but the Supertex model failed to model ANY behavior below >>>>>>>>> threshold, and the Supertex model had discontinuities in the ID/VDS >>>>>>>>> curve blending... guaranteed to cause simulator convergence issues. >>>>>>>>> >>>>>>>>> ...Jim Thompson >>>>>>>> >>>>>>>> I forgot to reference my old post (4/6/2005)... >>>>>>>> >>>>>>>> http://www.analog-innovations.com/SED/Compare2N7000Models.pdf >>>>>>>> >>>>>>>> Second page tells it all. >>>>>>>> >>>>>>>> ...Jim Thompson >>>>>>> >>>>>>> If you're actually designing boards with 2N7000s, any of those curves is about >>>>>>> as good as any other. Real-life parts will be all over the map. >>>>>> >>>>>> You didn't notice the discontinuities? >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>> Sure, but they are down in the "noise" of part-part differences. >>>> >>>> Refer back in the history of this group, and Win Hill's concern about >>>> operation in the subthreshold region. Use as a low noise amplifier is >>>> quite different from just using the device as a switch. >>>> >>>> ...Jim Thompson >>> >>> Here's a graph that I found in our PDATA folder for the 2N7000. I don't know >>> where it came from, possibly from Win. >>> >>> https://dl.dropboxusercontent.com/u/53724080/Parts/Fets/2n7000_off_leakage.pdf >>> >>> (people should sign and date everything that they create) >>> >>> What does "subthreshold" mean anyhow? It seeme to me that specified gate >>> thresholds are based on arbitrary drain currents. That curve above has no >>> threshold. >> >> Very pretty. What was V_GS? >> >> Cheers >> >> Phil Hobbs > > Do you mean Vds? I don't know.V_DS, right. Ah, well, I'll have to quit snuggling with my computer and actually do some measurements. ;) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
