Bulk

Probably a dumb question here.. but.. what happens to the DC characteristics of, say, a p-channel MOSFET if I pull the bulk potential above the source by a few volts? Will Id vs. Vgs change much?

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany
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Not a dumb question at all. It moves the channel around similar to the gate, so transconductance and threshold change.

Do you have a specific type in mind? Does it have a model available?

Let me know. If you don't have a model I can run a generic device and post the plots so you can see what it looks like.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

That would be great.

These guys, which have common bulk:

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I see a plot of changes vs. *substrate* bias but not bulk-- all the specs are at Vbs = 0. These parts are nicely specified for analog applications.

My idea is to use these as pass transistors for a number of independent high precision 10uA current sources of both polarities. Will current flow in or out of that pin? I was thinking to connect it to a voltage 2.5V beyond the rail.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany

^^^^^ oops, make that "source" Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany

You might also look at the SD5400 datasheet. A decade ago I've used them a lot for such stuff because the substrate was brought out on a separate package pin. Then they became boutiqueish and expensive :-(

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

Here you go....

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...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

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| 1962 | America: Land of the Free, Because of the Brave

Reply to
Jim Thompson

Thanks, Jim! Exactly what I need.

Best regards, Spehro Pefhany

--
"it\'s the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany

You're welcome!

When are you and "C" coming to Phoenix again?

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

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