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Guest

Mon Jan 06, 2020 3:03 am

Do you have a Spice model for SAV551 or something similar?

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Guest

Mon Jan 06, 2020 3:51 am

On 2020-01-05 20:03, jlarkin_at_highlandsniptechnology.com wrote:

> Do you have a Spice model for SAV551 or something similar?

I don't have any E-pHEMT models, and LTspice doesn't understand the

Avago datasheet models.

I've used this one in the past:

* Depletion pHEMT

* This is the datasheet model, except that LTspice doesn't understand a

bunch of

* the parameters given by Avago--we'll see if it works

..MODEL ATF38143_chip NMF( vto=-0.75, Beta=0.3, Lambda=0.07, Alpha=4,

+ B=0.8, Pb=0.7, Cgs=0.997E-12,

+ Cgd=0.176E-12, Rd=0.084, Rs=0.054, Kf=1e6, Af=1)

There are also these:

<http://www.hp.woodshot.com/hprfhelp/products/xrs/atf34xxx.htm>

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Mon Jan 06, 2020 5:23 am

On Sun, 5 Jan 2020 20:51:15 -0500, Phil Hobbs

<pcdhSpamMeSenseless_at_electrooptical.net> wrote:

.MODEL ATF38143_chip NMF( vto=-0.75, Beta=0.3, Lambda=0.07, Alpha=4,

+ B=0.8, Pb=0.7, Cgs=0.997E-12,

+ Cgd=0.176E-12, Rd=0.084, Rs=0.054, Kf=1e6, Af=1)

+ B=0.8, Pb=0.7, Cgs=0.997E-12,

+ Cgd=0.176E-12, Rd=0.084, Rs=0.054, Kf=1e6, Af=1)

Cool. Thanks. It works as a depletion mesfet. I can tweak that to make

it work more like a SAV541. Might add some drain inductance maybe. I

will use the 541 as a switch to discharge the cap in a linear ramp

generator, so the model can be a little crude; it's not likely to

oscillate!

Version 4

SHEET 1 880 680

WIRE 288 -96 64 -96

WIRE 64 -32 64 -96

WIRE 64 96 64 48

WIRE 128 96 64 96

WIRE 176 96 128 96

WIRE 64 160 64 96

WIRE 288 160 288 -96

WIRE -64 240 -128 240

WIRE 16 240 -64 240

WIRE -128 272 -128 240

WIRE 64 304 64 256

WIRE 288 304 288 240

WIRE -128 384 -128 352

FLAG 64 304 0

FLAG 288 304 0

FLAG -128 384 0

FLAG -64 240 G

FLAG 128 96 D

SYMBOL mesfet 16 160 R0

WINDOW 0 100 31 Left 2

WINDOW 3 89 65 Left 2

SYMATTR InstName Z1

SYMATTR Value SAV

SYMBOL voltage 288 144 R0

WINDOW 0 55 47 Left 2

WINDOW 3 63 77 Left 2

SYMATTR InstName V1

SYMATTR Value 5

SYMBOL res 48 -48 R0

WINDOW 0 -72 45 Left 2

WINDOW 3 -74 84 Left 2

SYMATTR InstName R1

SYMATTR Value 100

SYMBOL voltage -128 256 M0

WINDOW 0 62 58 Left 2

WINDOW 3 51 96 Left 2

WINDOW 123 0 0 Left 0

WINDOW 39 0 0 Left 0

SYMATTR InstName V2

SYMATTR Value SINE(-0.5 1 1)

TEXT -160 464 Left 2 !.MODEL SAV NMF( vto=-0.75, Beta=0.3,

Lambda=0.07, Alpha=4,\n+ B=0.8, Pb=0.7,

Cgs=0.997E-12,\n+ Cgd=0.176E-12, Rd=0.084,

Rs=0.054, Kf=1e6, Af=1)

TEXT 128 392 Left 2 !.tran 5

TEXT 376 320 Left 2 ;First cut at SAV541 model

TEXT 376 360 Left 2 ;using Phil's mesfet model

TEXT 432 408 Left 2 ;JL Jan 5 2020

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Guest

Mon Jan 06, 2020 8:02 pm

On 2020-01-05 22:23, jlarkin_at_highlandsniptechnology.com wrote:

On Sun, 5 Jan 2020 20:51:15 -0500, Phil Hobbs

pcdhSpamMeSenseless_at_electrooptical.net> wrote:

.MODEL ATF38143_chip NMF( vto=-0.75, Beta=0.3, Lambda=0.07, Alpha=4,

+ B=0.8, Pb=0.7, Cgs=0.997E-12,

+ Cgd=0.176E-12, Rd=0.084, Rs=0.054, Kf=1e6, Af=1)

Cool. Thanks. It works as a depletion mesfet. I can tweak that to make

it work more like a SAV541. Might add some drain inductance maybe. I

will use the 541 as a switch to discharge the cap in a linear ramp

generator, so the model can be a little crude; it's not likely to

oscillate!

pcdhSpamMeSenseless_at_electrooptical.net> wrote:

.MODEL ATF38143_chip NMF( vto=-0.75, Beta=0.3, Lambda=0.07, Alpha=4,

+ B=0.8, Pb=0.7, Cgs=0.997E-12,

+ Cgd=0.176E-12, Rd=0.084, Rs=0.054, Kf=1e6, Af=1)

Cool. Thanks. It works as a depletion mesfet. I can tweak that to make

it work more like a SAV541. Might add some drain inductance maybe. I

will use the 541 as a switch to discharge the cap in a linear ramp

generator, so the model can be a little crude; it's not likely to

oscillate!

The other link I posted has the package parasitics, which are probably

pretty similar.

Just for fun I instrumented your circuit and found that VAF is right

around 14 volts for this model. I think that might be a bit optimistic

for the Avago part.

<https://electrooptical.net/www/sed/JLphemtVAF.png>

<https://electrooptical.net/www/sed/JLphemtVAF.asc>

<https://electrooptical.net/www/sed/JLphemtVAF.plt>

Cheers

Phil Hobbs

--

Dr Philip C D Hobbs

Principal Consultant

ElectroOptical Innovations LLC / Hobbs ElectroOptics

Optics, Electro-optics, Photonics, Analog Electronics

Briarcliff Manor NY 10510

http://electrooptical.net

http://hobbs-eo.com

Guest

Wed Jan 08, 2020 3:41 pm

On 06.01.20 1:03 am, jlarkin_at_highlandsniptechnology.com wrote:

> Do you have a Spice model for SAV551 or something similar?

I don't, at least not for LTspice, but would be interested in one. The

obvious choice would be to use the ATF-55134 model from the

Agilent/Avago datasheet and hope it's close enough:

https://media.digikey.com/pdf/Data%20Sheets/Avago%20PDFs/ATF-55143.pdf

(page 16)

Unfortunately, that happens to use the ADS-flavoured quadratic Curtice

model, though, which other SPICEs don't implement. You could try and use

this as a basis for further fiddling:

..MODEL SAV551 NMF(Vto=0.3, Beta=0.444, B=0.8, Alpha=13, Lambda=0.072,

Rd=2.025, Rs=0.675, Cgs=0.6193E-12, Cgd=0.1435E-12, Pb=0.7, Fc=0.65)

This is a mechanical translation of the coefficients from the datasheet,

which might or might not give sensible results. You'd need to tune the B

value to match your measurementsâ€¦ Package parasitics could be included

in a SUBCKT as per the ATF-55143 datasheet.

Another option might be to just fit the model parameters to the data I

recall you posting elsewhere. The data for MCL's I_DS/V_DS curves is

available as well:

https://www.minicircuits.com/pages/s-params/SAV-551+_VIEW.pdf. You could

use their S parameters to get the parasitic reactances, and maybe

extract some more graphs to fit from an ADS sim if you have access to a

license. Never tried this, though, so caveat emptor.

On another note, does anyone know how NMF is supposed to work for noise

simulations in LTspice? The results seem wildly off (too large by orders

of magnitude), but I can't find any reference as to which model it is

even supposed to use (McWhorther 1/f noise plus broadband noise inferred

from transconductance?).

â€” David

Guest

Wed Jan 08, 2020 5:19 pm

On Wed, 8 Jan 2020 13:41:40 +0000, David Nadlinger

<david_at_klickverbot.at> wrote:

On 06.01.20 1:03 am, jlarkin_at_highlandsniptechnology.com wrote:

Do you have a Spice model for SAV551 or something similar?

I don't, at least not for LTspice, but would be interested in one. The

obvious choice would be to use the ATF-55134 model from the

Agilent/Avago datasheet and hope it's close enough:

https://media.digikey.com/pdf/Data%20Sheets/Avago%20PDFs/ATF-55143.pdf

(page 16)

Unfortunately, that happens to use the ADS-flavoured quadratic Curtice

model, though, which other SPICEs don't implement. You could try and use

this as a basis for further fiddling:

.MODEL SAV551 NMF(Vto=0.3, Beta=0.444, B=0.8, Alpha=13, Lambda=0.072,

Rd=2.025, Rs=0.675, Cgs=0.6193E-12, Cgd=0.1435E-12, Pb=0.7, Fc=0.65)

This is a mechanical translation of the coefficients from the datasheet,

which might or might not give sensible results. You'd need to tune the B

value to match your measurements… Package parasitics could be included

in a SUBCKT as per the ATF-55143 datasheet.

Another option might be to just fit the model parameters to the data I

recall you posting elsewhere. The data for MCL's I_DS/V_DS curves is

available as well:

https://www.minicircuits.com/pages/s-params/SAV-551+_VIEW.pdf. You could

use their S parameters to get the parasitic reactances, and maybe

extract some more graphs to fit from an ADS sim if you have access to a

license. Never tried this, though, so caveat emptor.

On another note, does anyone know how NMF is supposed to work for noise

simulations in LTspice? The results seem wildly off (too large by orders

of magnitude), but I can't find any reference as to which model it is

even supposed to use (McWhorther 1/f noise plus broadband noise inferred

from transconductance?).

— David

Do you have a Spice model for SAV551 or something similar?

I don't, at least not for LTspice, but would be interested in one. The

obvious choice would be to use the ATF-55134 model from the

Agilent/Avago datasheet and hope it's close enough:

https://media.digikey.com/pdf/Data%20Sheets/Avago%20PDFs/ATF-55143.pdf

(page 16)

Unfortunately, that happens to use the ADS-flavoured quadratic Curtice

model, though, which other SPICEs don't implement. You could try and use

this as a basis for further fiddling:

.MODEL SAV551 NMF(Vto=0.3, Beta=0.444, B=0.8, Alpha=13, Lambda=0.072,

Rd=2.025, Rs=0.675, Cgs=0.6193E-12, Cgd=0.1435E-12, Pb=0.7, Fc=0.65)

This is a mechanical translation of the coefficients from the datasheet,

which might or might not give sensible results. You'd need to tune the B

value to match your measurements… Package parasitics could be included

in a SUBCKT as per the ATF-55143 datasheet.

Another option might be to just fit the model parameters to the data I

recall you posting elsewhere. The data for MCL's I_DS/V_DS curves is

available as well:

https://www.minicircuits.com/pages/s-params/SAV-551+_VIEW.pdf. You could

use their S parameters to get the parasitic reactances, and maybe

extract some more graphs to fit from an ADS sim if you have access to a

license. Never tried this, though, so caveat emptor.

On another note, does anyone know how NMF is supposed to work for noise

simulations in LTspice? The results seem wildly off (too large by orders

of magnitude), but I can't find any reference as to which model it is

even supposed to use (McWhorther 1/f noise plus broadband noise inferred

from transconductance?).

— David

Thanks, I'll plug that in and see how it compares to a real part.

I'm using the SAV541 to discharge a linear-ramp capacitor, so the only

parasitic of great concern is drain inductance. I can measure that

with TDR and add it to my circuit as a discrete inductor.

The trick with grounded-cap ramps is to keep the early part clean,

linear and not ringing. The faster the discharge switch, the more it

all wants to ring.

--

John Larkin Highland Technology, Inc

lunatic fringe electronics

elektroda.net NewsGroups Forum Index - Electronics Design - **Phil,**