1. Home
  2. Hobby Electronics Basics
  3. 2N7000 Spice Model

2N7000 Spice Model

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

-- | 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

formatting link
| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Reply to
Jim Thompson
Loading thread data ...

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?

--

John Larkin         Highland Technology, Inc 

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

I would hope to see some electrical behaviour!

--
Mike Perkins 
Video Solutions Ltd 
www.videosolutions.ltd.uk
Reply to
Mike Perkins

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

--
| 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 to
Jim Thompson

I forgot to reference my old post (4/6/2005)...

formatting link

Second page tells it all. ...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 to
Jim Thompson

Fairchild FQD2N100 model attached.

Reply to
Robert Baer

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.

--

John Larkin                  Highland Technology Inc 
www.highlandtechnology.com   jlarkin at highlandtechnology dot com    

Precision electronic instrumentation
Reply to
John Larkin

You didn't notice the discontinuities? ...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 to
Jim Thompson

Sure, 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
Reply to
John Larkin

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 to
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.

formatting link

(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 to
John Larkin

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 to
Jim Thompson

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 to
Jim Thompson

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 to
Phil Hobbs

Not if the board function depends on sub-threshold behavior!

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

Do you mean Vds? I don't know.

--

John Larkin         Highland Technology, Inc 

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

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
Reply to
Phil Hobbs

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.