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[mathcad] Short gate MESFET model

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[mathcad] Short gate MESFET model
Author: Richard Balmer    Posted: Fri, 6 Jun 2008 15:00:34 +0100
Hi, I have implemented a Mathcad worksheet to model a long channel MESFET based on formulae in Sze (basically the same formulae as a JFET). I would like to model a short channel MESFET where velocity saturation comes into play, but am having difficulty generating a coherent transistor output characteristic (the current at the transition between active and saturation regions doesn't match). In the active part of the characteristic, the current is mobility dependent (and Vds, Vgs). In the saturation part of the characteristic, the current is saturation velocity dependent (and Vgs), but the voltage drop along the channel is unknown. I am using the Mathcad 'Find' function to solve 2 equations with 2 unknowns, Ids and p. Is anyone familiar with this problem? Many thanks if you can help. Richard Balmer Dr Richard Balmer Element Six Ltd. Reception: +44 1344 638200 Direct Line: +44 1344 638220 ************************************************************************ < < Privileged, confidential and/or copyright information may be contained < in this e-mail. This e-mail is for the use only of the intended addressee. < If you are not the intended addressee, or the person responsible for < delivering it to the intended addressee, you may not copy, forward, < disclose or otherwise use it or any part of it in any way whatsoever. < To do so is prohibited and may be unlawful. If you receive this e-mail < by mistake please advise the sender immediately by using the reply < facility in your e-mail software. < < Element Six may monitor the content of e-mails sent < and received via its network for the purposes of ensuring compliance < with its policies and procedures. < < This footnote also confirms that this email message has been swept < for the presence of computer viruses. < < ************************************************************************

Re: [mathcad] Short gate MESFET model
Author: Eden Mei    Posted: Fri, 6 Jun 2008 12:12:04 -0700
Posting the sheet would be useful TTFN From: "richard.balmer" To: "mathcad" Sent: Friday, June 06, 2008 7:00 AM Subject: [mathcad] Short gate MESFET model Hi, I have implemented a Mathcad worksheet to model a long channel MESFET based on formulae in Sze (basically the same formulae as a JFET). I would like to model a short channel MESFET where velocity saturation comes into play, but am having difficulty generating a coherent transistor output characteristic (the current at the transition between active and saturation regions doesn't match). In the active part of the characteristic, the current is mobility dependent (and Vds, Vgs). In the saturation part of the characteristic, the current is saturation velocity dependent (and Vgs), but the voltage drop along the channel is unknown. I am using the Mathcad 'Find' function to solve 2 equations with 2 unknowns, Ids and p. Is anyone familiar with this problem? Many thanks if you can help. Richard Balmer Dr Richard Balmer Element Six Ltd. Reception: +44 1344 638200 Direct Line: +44 1344 638220 ************************************************************************ < Privileged, confidential and/or copyright information may be contained < in this e-mail. This e-mail is for the use only of the intended addressee. < If you are not the intended addressee, or the person responsible for < delivering it to the intended addressee, you may not copy, forward, < disclose or otherwise use it or any part of it in any way whatsoever. < To do so is prohibited and may be unlawful. If you receive this e-mail < by mistake please advise the sender immediately by using the reply < facility in your e-mail software. < < Element Six may monitor the content of e-mails sent < and received via its network for the purposes of ensuring compliance < with its policies and procedures. < < This footnote also confirms that this email message has been swept < for the presence of computer viruses. < < ************************************************************************

RE: [mathcad] Short gate MESFET model
Author: Stuart Bruff    Posted: Mon, 9 Jun 2008 01:20:11 +0100
I'm not familar with the subject area, but if you could post a worksheet someone might be able to give some advice. Stuart From: "richard.balmer" "mailto:richard.balmer" Sent: 06 June 2008 3:01 PM To: "mathcad" Subject: [mathcad] Short gate MESFET model Hi, I have implemented a Mathcad worksheet to model a long channel MESFET based on formulae in Sze (basically the same formulae as a JFET). I would like to model a short channel MESFET where velocity saturation comes into play, but am having difficulty generating a coherent transistor output characteristic (the current at the transition between active and saturation regions doesn't match). In the active part of the characteristic, the current is mobility dependent (and Vds, Vgs). In the saturation part of the characteristic, the current is saturation velocity dependent (and Vgs), but the voltage drop along the channel is unknown. I am using the Mathcad 'Find' function to solve 2 equations with 2 unknowns, Ids and p. Is anyone familiar with this problem? Many thanks if you can help. Richard Balmer Dr Richard Balmer Element Six Ltd. Reception: +44 1344 638200 Direct Line: +44 1344 638220 ************************************************************************ < Privileged, confidential and/or copyright information may be contained < in this e-mail. This e-mail is for the use only of the intended addressee. < If you are not the intended addressee, or the person responsible for < delivering it to the intended addressee, you may not copy, forward, < disclose or otherwise use it or any part of it in any way whatsoever. < To do so is prohibited and may be unlawful. If you receive this e-mail < by mistake please advise the sender immediately by using the reply < facility in your e-mail software. < < Element Six may monitor the content of e-mails sent < and received via its network for the purposes of ensuring compliance < with its policies and procedures. < < This footnote also confirms that this email message has been swept < for the presence of computer viruses. < < ************************************************************************ "mathcad" Hosted by: Adept Scientific http://www.adeptscience.com List Archive: http://lists.adeptscience.co.uk/ leave the mailing list (see below) and re-join by sending a blank email from are currently subscribed to mathcad as: "stuartbruff" To unsubscribe send a blank email to "leave-120240-494329S"

RE: [mathcad] Short gate MESFET model
Author: Richard Balmer    Posted: Mon, 9 Jun 2008 13:54:15 +0100
You're right, sorry, should have posted this before. Richard Balmer "Stuart Bruff" "stuartbruff" 09/06/2008 01:20 Please respond to "mathcad" To "mathcad" cc bcc Fax to Subject RE: [mathcad] Short gate MESFET model I'm not familar with the subject area, but if you could post a worksheet someone might be able to give some advice. Stuart From: "richard.balmer" "mailto:richard.balmer" Sent: 06 June 2008 3:01 PM To: "mathcad" Subject: [mathcad] Short gate MESFET model Hi, I have implemented a Mathcad worksheet to model a long channel MESFET based on formulae in Sze (basically the same formulae as a JFET). I would like to model a short channel MESFET where velocity saturation comes into play, but am having difficulty generating a coherent transistor output characteristic (the current at the transition between active and saturation regions doesn't match). In the active part of the characteristic, the current is mobility dependent (and Vds, Vgs). In the saturation part of the characteristic, the current is saturation velocity dependent (and Vgs), but the voltage drop along the channel is unknown. I am using the Mathcad 'Find' function to solve 2 equations with 2 unknowns, Ids and p. Is anyone familiar with this problem? Many thanks if you can help. Richard Balmer Dr Richard Balmer Element Six Ltd. Reception: +44 1344 638200 Direct Line: +44 1344 638220 ************************************************************************ < Privileged, confidential and/or copyright information may be contained < in this e-mail. This e-mail is for the use only of the intended addressee. < If you are not the intended addressee, or the person responsible for < delivering it to the intended addressee, you may not copy, forward, < disclose or otherwise use it or any part of it in any way whatsoever. < To do so is prohibited and may be unlawful. If you receive this e-mail < by mistake please advise the sender immediately by using the reply < facility in your e-mail software. < < Element Six may monitor the content of e-mails sent < and received via its network for the purposes of ensuring compliance < with its policies and procedures. < < This footnote also confirms that this email message has been swept < for the presence of computer viruses. < < ************************************************************************ "mathcad" Hosted by: Adept Scientific http://www.adeptscience.com List Archive: http://lists.adeptscience.co.uk/ leave the mailing list (see below) and re-join by sending a blank email You are currently subscribed to mathcad as: "stuartbruff" To unsubscribe send a blank email to "leave-120240-494329S"
Attachments:  GaAs MESFET v3.xmcdz

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