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Sumitomo GaAs and GaN FETs

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Phil Hobbs
Guest

Tue Jan 10, 2017 11:08 pm   



I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)

The Cree CGHV27015S has an input capacitance of 3 pF and IDmax of 900
mA. I'd sure like to have one about 1/10 that size. GaAs pHEMTs are
great, but their 1/f noise is horrible, so I'd like to try out a few GaN
ones.

Anybody tried them?

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

Phil Hobbs
Guest

Tue Jan 10, 2017 11:12 pm   



On 01/10/2017 11:08 AM, Phil Hobbs wrote:
Quote:
I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)

The Cree CGHV27015S has an input capacitance of 3 pF and IDmax of 900
mA. I'd sure like to have one about 1/10 that size. GaAs pHEMTs are
great, but their 1/f noise is horrible, so I'd like to try out a few GaN
ones.

Anybody tried them?


(Obligatory on-topic content: Sumitomo also lists some, e.g. the
SGNE010MK, but nobody seems to stock them.)

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

John Larkin
Guest

Wed Jan 11, 2017 12:33 am   



On Tue, 10 Jan 2017 11:08:26 -0500, Phil Hobbs
<pcdhSpamMeSenseless_at_electrooptical.net> wrote:

Quote:
I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)

The Cree CGHV27015S has an input capacitance of 3 pF and IDmax of 900
mA. I'd sure like to have one about 1/10 that size. GaAs pHEMTs are
great, but their 1/f noise is horrible, so I'd like to try out a few GaN
ones.

Anybody tried them?

Cheers

Phil Hobbs


We are just now updating our inventory database to qualify
replacements for the eol NEC NE3508 and NE3509 smallish depletion-mode
phemts. C is doing that, and she's ordered some samples to test, just
to make sure. I'll post what we find, later this week.

These are small parts, for discharging ramps and such, Idss in the
roughly 40 mA range. Some parts have low drain voltage ratings, like 4
volts, and we have some situations where we may go a bit above that.
So we'll test them to see what the real numbers are. Some phemts are
OK at 4x their rated drain voltage; RF people write weird specs, and
seldom supply DC curves. Pump in some RF, and more comes out; that's
all you need to know. Some fets have the gate named "RF IN" and the
drain "RF OUT" and the part is called an "amplifier."

We use a couple of the Avago enhancement parts, which are usually
easier to drive in switched apps, but they are not drop-ins for the
older depletion fets.

The CEL web site is depressing. Most of the cool older RF parts are
discontinued.

We are playing with the EPC GaN chip-scale parts, as pulse generator
outputs in the 1-amp range, but they are a little hard to handle and
are seriously sole-source. The GaN parts are mostly aimed at power
apps. Are there any little ones?






--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Phil Hobbs
Guest

Wed Jan 11, 2017 2:54 am   



On 01/10/2017 12:33 PM, John Larkin wrote:
Quote:
On Tue, 10 Jan 2017 11:08:26 -0500, Phil Hobbs
pcdhSpamMeSenseless_at_electrooptical.net> wrote:

I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)

The Cree CGHV27015S has an input capacitance of 3 pF and IDmax of 900
mA. I'd sure like to have one about 1/10 that size. GaAs pHEMTs are
great, but their 1/f noise is horrible, so I'd like to try out a few GaN
ones.

Anybody tried them?

Cheers

Phil Hobbs

We are just now updating our inventory database to qualify
replacements for the eol NEC NE3508 and NE3509 smallish depletion-mode
phemts. C is doing that, and she's ordered some samples to test, just
to make sure. I'll post what we find, later this week.

These are small parts, for discharging ramps and such, Idss in the
roughly 40 mA range. Some parts have low drain voltage ratings, like 4
volts, and we have some situations where we may go a bit above that.
So we'll test them to see what the real numbers are. Some phemts are
OK at 4x their rated drain voltage; RF people write weird specs, and
seldom supply DC curves. Pump in some RF, and more comes out; that's
all you need to know. Some fets have the gate named "RF IN" and the
drain "RF OUT" and the part is called an "amplifier."

We use a couple of the Avago enhancement parts, which are usually
easier to drive in switched apps, but they are not drop-ins for the
older depletion fets.

The CEL web site is depressing. Most of the cool older RF parts are
discontinued.

We are playing with the EPC GaN chip-scale parts, as pulse generator
outputs in the 1-amp range, but they are a little hard to handle and
are seriously sole-source. The GaN parts are mostly aimed at power
apps. Are there any little ones?


Not that I know of. I'm looking at the Broadcom/Avago VMMK-1225 pHEMT,
which looks really cool, even if it's $8: Ciss = 1 pF, g_M ~ 1 S. That
ought to be quiet if they've managed to control the 1/f noise.

My fave e-pHEMT is the ATF55143, but I haven't tried many. That's one
of two device candidates for that 100-ps $2 TDR.

For switching and normal FET-type stuff I really like the SKY65050
because it has a decently large drain impedance, not like the
Avago/Broadcom ATF38143, which doesn't even work as a source follower
because it's so limp. Cascoding cleans it right up, of course. Their
flatband noise is awesome, about 0.3 nV for the Broadcom part and 0.4 nV
for the Skyworks (1 Hz, natch).

Unfortunately the ATF38143 has a 1/f corner of about 10 MHz, and the
SKY65050's is 30 MHz.

The ATF38143 also has that neat self-biasing feature--if you leave the
gate open, it floats negative by a couple of hundred millivolts. I used
that feature in an amp once (it was a special for a research lab, so it
didn't need to work in mass production).

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


Guest

Wed Jan 11, 2017 3:14 am   



Quote:
Phemts as source followers is a frightening concept. A cascoded
follower is terrifying.


Unfortunately the ATF38143 has a 1/f corner of about 10 MHz, and the
SKY65050's is 30 MHz.

The ATF38143 also has that neat self-biasing feature--if you leave the
gate open, it floats negative by a couple of hundred millivolts.  I used
that feature in an amp once (it was a special for a research lab, so it
didn't need to work in mass production).

Weird gadgets.

Can you get that Skyworks part? Digikey is discouraging.

http://www.digikey.com/product-detail/en/skyworks-solutions-inc/SKY65050-372LF/863-1067-1-ND/2052199


Mouser has like 9000 of them.

Invest in reels!

Cheers

Phil Hobbs


Guest

Wed Jan 11, 2017 6:54 am   



On Wednesday, January 11, 2017 at 3:08:40 AM UTC+11, Phil Hobbs wrote:
Quote:
I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's anybody I've
missed, let's compare notes.)


I was doing it back in the 1980's - fast beam-blanking electronics for electron beam testers. The emphasis was more on broad-band transistor - BFR92 and the like - than on specialised microwave transistors.

We did use one Hewlett-Packard RF power transistor to let us switch a useful amount of current quickly - I'd tried to make a Percival distributed amplifier to put a bunch of smaller transistors in parallel, but it hadn't been quick enough - 800psec versus 500psec.

--
Bill Sloman, Sydney

Phil Hobbs
Guest

Wed Jan 11, 2017 7:46 am   



On 01/10/2017 08:07 PM, John Larkin wrote:
Quote:
On Tue, 10 Jan 2017 14:54:49 -0500, Phil Hobbs
pcdhSpamMeSenseless_at_electrooptical.net> wrote:

On 01/10/2017 12:33 PM, John Larkin wrote:
On Tue, 10 Jan 2017 11:08:26 -0500, Phil Hobbs
pcdhSpamMeSenseless_at_electrooptical.net> wrote:

I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)

The Cree CGHV27015S has an input capacitance of 3 pF and IDmax of 900
mA. I'd sure like to have one about 1/10 that size. GaAs pHEMTs are
great, but their 1/f noise is horrible, so I'd like to try out a few GaN
ones.

Anybody tried them?

Cheers

Phil Hobbs

We are just now updating our inventory database to qualify
replacements for the eol NEC NE3508 and NE3509 smallish depletion-mode
phemts. C is doing that, and she's ordered some samples to test, just
to make sure. I'll post what we find, later this week.

These are small parts, for discharging ramps and such, Idss in the
roughly 40 mA range. Some parts have low drain voltage ratings, like 4
volts, and we have some situations where we may go a bit above that.
So we'll test them to see what the real numbers are. Some phemts are
OK at 4x their rated drain voltage; RF people write weird specs, and
seldom supply DC curves. Pump in some RF, and more comes out; that's
all you need to know. Some fets have the gate named "RF IN" and the
drain "RF OUT" and the part is called an "amplifier."

We use a couple of the Avago enhancement parts, which are usually
easier to drive in switched apps, but they are not drop-ins for the
older depletion fets.

The CEL web site is depressing. Most of the cool older RF parts are
discontinued.

We are playing with the EPC GaN chip-scale parts, as pulse generator
outputs in the 1-amp range, but they are a little hard to handle and
are seriously sole-source. The GaN parts are mostly aimed at power
apps. Are there any little ones?

Not that I know of. I'm looking at the Broadcom/Avago VMMK-1225 pHEMT,
which looks really cool, even if it's $8: Ciss = 1 pF, g_M ~ 1 S. That
ought to be quiet if they've managed to control the 1/f noise.

My fave e-pHEMT is the ATF55143, but I haven't tried many. That's one
of two device candidates for that 100-ps $2 TDR.

We use that one. Poke the gate positive into conduction, and it really
turns on hard. I conjecture some sort of bipolar effect.

Abs max specs aren't everything.




For switching and normal FET-type stuff I really like the SKY65050
because it has a decently large drain impedance, not like the
Avago/Broadcom ATF38143, which doesn't even work as a source follower
because it's so limp. Cascoding cleans it right up, of course. Their
flatband noise is awesome, about 0.3 nV for the Broadcom part and 0.4 nV
for the Skyworks (1 Hz, natch).

Phemts as source followers is a frightening concept.


For the Samsung labs front end, I added a free-of-charge calibrator that
made really triangular triangle waves. A tri wave plus a really small
cap (<0.1 pF between two traces) makes a nice square wave current source
for calibrating nanoamp front ends. It needed the calibration, and I
wanted to learn more about how pHEMTs behaved. So there was a pHEMT
follower driving a two-pHEMT Schmitt trigger and a pHEMT integrator.

It failed completely with ATF38143s, but worked fine with SKY65050s.

I haven't tried cascoding a pHEMT follower, although it might be
useful--I do quite a few cascoded bootstraps for PDs.

Cheers

Phil Hobbs




Quote:
A cascoded
follower is terrifying.


Unfortunately the ATF38143 has a 1/f corner of about 10 MHz, and the
SKY65050's is 30 MHz.

The ATF38143 also has that neat self-biasing feature--if you leave the
gate open, it floats negative by a couple of hundred millivolts. I used
that feature in an amp once (it was a special for a research lab, so it
didn't need to work in mass production).

Weird gadgets.

Can you get that Skyworks part? Digikey is discouraging.

http://www.digikey.com/product-detail/en/skyworks-solutions-inc/SKY65050-372LF/863-1067-1-ND/2052199





--
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

John Larkin
Guest

Wed Jan 11, 2017 8:07 am   



On Tue, 10 Jan 2017 14:54:49 -0500, Phil Hobbs
<pcdhSpamMeSenseless_at_electrooptical.net> wrote:

Quote:
On 01/10/2017 12:33 PM, John Larkin wrote:
On Tue, 10 Jan 2017 11:08:26 -0500, Phil Hobbs
pcdhSpamMeSenseless_at_electrooptical.net> wrote:

I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)

The Cree CGHV27015S has an input capacitance of 3 pF and IDmax of 900
mA. I'd sure like to have one about 1/10 that size. GaAs pHEMTs are
great, but their 1/f noise is horrible, so I'd like to try out a few GaN
ones.

Anybody tried them?

Cheers

Phil Hobbs

We are just now updating our inventory database to qualify
replacements for the eol NEC NE3508 and NE3509 smallish depletion-mode
phemts. C is doing that, and she's ordered some samples to test, just
to make sure. I'll post what we find, later this week.

These are small parts, for discharging ramps and such, Idss in the
roughly 40 mA range. Some parts have low drain voltage ratings, like 4
volts, and we have some situations where we may go a bit above that.
So we'll test them to see what the real numbers are. Some phemts are
OK at 4x their rated drain voltage; RF people write weird specs, and
seldom supply DC curves. Pump in some RF, and more comes out; that's
all you need to know. Some fets have the gate named "RF IN" and the
drain "RF OUT" and the part is called an "amplifier."

We use a couple of the Avago enhancement parts, which are usually
easier to drive in switched apps, but they are not drop-ins for the
older depletion fets.

The CEL web site is depressing. Most of the cool older RF parts are
discontinued.

We are playing with the EPC GaN chip-scale parts, as pulse generator
outputs in the 1-amp range, but they are a little hard to handle and
are seriously sole-source. The GaN parts are mostly aimed at power
apps. Are there any little ones?

Not that I know of. I'm looking at the Broadcom/Avago VMMK-1225 pHEMT,
which looks really cool, even if it's $8: Ciss = 1 pF, g_M ~ 1 S. That
ought to be quiet if they've managed to control the 1/f noise.

My fave e-pHEMT is the ATF55143, but I haven't tried many. That's one
of two device candidates for that 100-ps $2 TDR.


We use that one. Poke the gate positive into conduction, and it really
turns on hard. I conjecture some sort of bipolar effect.

Abs max specs aren't everything.



Quote:

For switching and normal FET-type stuff I really like the SKY65050
because it has a decently large drain impedance, not like the
Avago/Broadcom ATF38143, which doesn't even work as a source follower
because it's so limp. Cascoding cleans it right up, of course. Their
flatband noise is awesome, about 0.3 nV for the Broadcom part and 0.4 nV
for the Skyworks (1 Hz, natch).


Phemts as source followers is a frightening concept. A cascoded
follower is terrifying.

Quote:

Unfortunately the ATF38143 has a 1/f corner of about 10 MHz, and the
SKY65050's is 30 MHz.

The ATF38143 also has that neat self-biasing feature--if you leave the
gate open, it floats negative by a couple of hundred millivolts. I used
that feature in an amp once (it was a special for a research lab, so it
didn't need to work in mass production).


Weird gadgets.

Can you get that Skyworks part? Digikey is discouraging.

http://www.digikey.com/product-detail/en/skyworks-solutions-inc/SKY65050-372LF/863-1067-1-ND/2052199



--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

Tim Williams
Guest

Thu Jan 12, 2017 6:33 am   



"Phil Hobbs" <pcdhSpamMeSenseless_at_electrooptical.net> wrote in message
news:EJadnSBZW_Nnm-jFnZ2dnUU7-RvNnZ2d_at_supernews.com...
Quote:
I'm looking at small(ish) GaN HEMTs, mostly for interest because I
collect parts like that. (JL and I are probably the only folks here who
routinely use microwave transistors at baseband--if there's arebody I've
missed, let's compare notes.)


OT: I read "arebody" as "arsebody". Oh Freud... :^)

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com

elektroda.net NewsGroups Forum Index - Electronics Design - Sumitomo GaAs and GaN FETs

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