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Ian Collins
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Anyone got a SPICE (LTspice preferred) model for the SKY65050? Looking at it for a project.
J
John Larkin
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On Tue, 1 Nov 2022 10:01:09 -0700 (PDT), Ian Collins
<collinsip@gmail.com> wrote:
>Anyone got a SPICE (LTspice preferred) model for the SKY65050? Looking at it for a project.
I have LT Spice models of the MiniCircuits SAV541 and SAV551 phemts,
sorta similar parts but enhancment mode. Based on Phil Hobbs model,
tweaked a bit based on measurements. They seem to work for my
applications, fast switching and some Colpitts oscillators. They don\'t
include package parasitics.
You can have them and tweak for the Sky part.
It\'s always a hassle, trying to use RF parts in time domain, namely in
Spice.
What are you doing?
<collinsip@gmail.com> wrote:
>Anyone got a SPICE (LTspice preferred) model for the SKY65050? Looking at it for a project.
I have LT Spice models of the MiniCircuits SAV541 and SAV551 phemts,
sorta similar parts but enhancment mode. Based on Phil Hobbs model,
tweaked a bit based on measurements. They seem to work for my
applications, fast switching and some Colpitts oscillators. They don\'t
include package parasitics.
You can have them and tweak for the Sky part.
It\'s always a hassle, trying to use RF parts in time domain, namely in
Spice.
What are you doing?
P
Phil Hobbs
Guest
Ian Collins wrote:
The ones I have are based on a destroked version of an Avago model for a
fancier simulator than I possess.
From my omnibus SPICE library:
===================
* 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)
* PH 2/10/20: Turns out that Avago\'s flicker noise amplitude Kf is 18
orders of
* magnitude too high--they had 1E6 and it\'s more like 5E-12 for a 10 MHz
* 1/f corner frequency. Hacked it to be 1/f (AF=2) and adjusted KF for a
* 24-MHz 1/f corner, which should be roughly right.
..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=5e-11, Af=2)
* Fixed to be enhancement
..MODEL SAV551_chip AKO:ATF38143_chip VTO=0.08
==================
JL\'s models are likely to be better in the time domain, since he\'s put
in actual measurement data.
The SKY65050 has about 1-2 dB higher flatband noise (0.35-0.4
nV/sqrt(Hz) than the old Avago parts. On the other hand, it has a
considerably higher drain impedance (i.e. higher Early voltage or
whatever it\'s called in a FET) than the Avago parts, which is a big win
in time domain stuff.
Using a pHEMT as a follower is a depressing experience--some of them
have gains of, like, 0.6 as followers.
Cascoding with a SiGe BJT such as a BFP640 makes them amazingly better,
but requires, *ahem* a bit of care.
If you do a babytalk groups search in SED for the string
\"pHEMT\" \"SiGe\" \"cascode\"
a whole bunch of stuff about that will come up.
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
The ones I have are based on a destroked version of an Avago model for a
fancier simulator than I possess.
From my omnibus SPICE library:
===================
* 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)
* PH 2/10/20: Turns out that Avago\'s flicker noise amplitude Kf is 18
orders of
* magnitude too high--they had 1E6 and it\'s more like 5E-12 for a 10 MHz
* 1/f corner frequency. Hacked it to be 1/f (AF=2) and adjusted KF for a
* 24-MHz 1/f corner, which should be roughly right.
..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=5e-11, Af=2)
* Fixed to be enhancement
..MODEL SAV551_chip AKO:ATF38143_chip VTO=0.08
==================
JL\'s models are likely to be better in the time domain, since he\'s put
in actual measurement data.
The SKY65050 has about 1-2 dB higher flatband noise (0.35-0.4
nV/sqrt(Hz) than the old Avago parts. On the other hand, it has a
considerably higher drain impedance (i.e. higher Early voltage or
whatever it\'s called in a FET) than the Avago parts, which is a big win
in time domain stuff.
Using a pHEMT as a follower is a depressing experience--some of them
have gains of, like, 0.6 as followers.
Cascoding with a SiGe BJT such as a BFP640 makes them amazingly better,
but requires, *ahem* a bit of care.
If you do a babytalk groups search in SED for the string
\"pHEMT\" \"SiGe\" \"cascode\"
a whole bunch of stuff about that will come up.
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