Re: LTSpice model for a SiC MOSFET

On Tue, 20 May 2025 03:21:37 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:

On 19/05/2025 11:33 pm, legg wrote:

On Mon, 19 May 2025 12:23:54 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
 

On 19/05/2025 12:15 am, john larkin wrote:

On Sun, 18 May 2025 18:11:58 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
>

I'm looking at a problem where somebody wants to step down a 1kV low
current source to 3.3V.
>
The Baxandall class-D oscillator could do it, but it needs a pair 1.7kV
MOSFETs for the job. The Infineon SiC IMH170R450M1 would do it - though
it's a much higher current part (10A) than the job needs (about 1mA).
>
I've dived into the Infineon rabbit-hole which promises LTSpice models,
but wasn't able to find one.
>
Does anybody know of a similar - ideally cheaper and smaller - part for
which there is an LTSpice model?

>
I use a Cree/Wolfspeed 1200v part, C2M0280120D, in my Pockels Cell
driver.
>
https://www.dropbox.com/scl/fi/5arhyamrp0bl3tgb2fasn/DSC02771.JPG?rlkey=3ttcc2yt6s9nrtdouuv3aneol&raw=1
>
They do have an LT Spice model library that works.
>
Gate drive for SiC parts is a bear. I did it myself, but I think there
are chips for that now.
>
There are multi-kilovolt silicon mosfets too.
>
Baxandal looks to be inefficient and expensive as a low power
converter. The drain swing is 2x the supply voltage, and it needs two
fets and a difficult custom transformer.

>
It isn't going to be inefficient. That configuration is famous efficient.
>
The drain swing is actually 1.67 times the supply voltage, but it does
need two switching devices and a specially wound transformer (and we
know how reluctant you are to design them or get them made).
>
It is probably going to be too expensive for the application, and we'd
be grateful for your insights into a cheaper alternative. I can't think
of one.

 
I'd keep it simple and repurpose a backwards commodity CCFL ($0.50)
  transformer, in a low frequency (20-50KHz) buck regulator 'of sorts'.

>
Cold cathode fluorescent lamps are cranky beasts, and Jim Williams
exploited the Baxandal configuration to get the voltages they need out
of low voltage supplies, using bipolar transistor switches. I would not
be all that optimistic about finding a CCFL transformer that I could
repurpose.
>
Designing a transformer for the job isn't all that difficult and finding
a local transformer shop to wind it wasn't all that hard when I did
something similar in the Netherlands  some twenty years ago.
>

A 1KV mosfet (why SIC?) would act as it's own TVS if the source was
really self-limited. 2$

>
The SIC part costs about $5.00. The guy I'm talking to came up with $200
regular silicon part with a higher on resistance and about ten times the
internal capacitances. I'm not recommending SiC on principle - the
limited search I did came up with a SiC part which looked as if might
work, even if still too expensive to be attractive.
>

Mfr Part # Price Mfr Drain to Source Voltage (Vdss) Current
- Continuous Drain (Id) @ 25°C Drive Voltage (Max Rds On, Min Rds On)
Rds On (Max) @ Id, Vgs Vgs(th) (Max) @ Id Gate Charge (Qg) (Max)
@ Vgs Vgs (Max) Input Capacitance (Ciss) (Max) @ Vds
IXTP02N120P 4.31 Littelfuse Inc. 1200 V 200mA (Tc) 10V
75Ohm @ 100mA, 10V 4V @ 100µA 4.7 nC @ 10 V ±20V 104 pF
@ 25 V
IXTA06N120P-TRL 7.57 Littelfuse Inc. 1200 V 600mA (Tc) 10V
34Ohm @ 300mA, 10V 4V @ 50µA 13.3 nC @ 10 V ±30V 236 pF
@ 25 V
STF8NK100Z 8.5 STMicro 1000 V 6.5A (Tc) 10V
1.85Ohm @ 3.15A, 10V 4.5V @ 100µA 102 nC @ 10 V ±30V 2180
pF @ 25 V
IXTY02N120P 3.07 Littelfuse Inc. 1200 V 200mA (Tc) 10V
75Ohm @ 500mA, 10V 4V @ 100µA 4.7 nC @ 10 V ±20V 104 pF
@ 25 V
IXTY01N100 5.22 Littelfuse Inc. 1000 V 100mA (Tc) 10V
80Ohm @ 100mA, 10V 4.5V @ 25µA 6.9 nC @ 10 V ±20V 54 pF
@ 25 V
STF5NK100Z 6.65 STMicro  1000 V 3.5A (Tc) 10V
3.7Ohm @ 1.75A, 10V 4.5V @ 100µA 59 nC @ 10 V ±30V 1154
pF @ 25 V
IXTA06N120P 7.63 Littelfuse Inc. 1200 V 600mA (Tc) 10V
32Ohm @ 300mA, 10V 4.5V @ 50µA 13.3 nC @ 10 V ±20V 270 pF
@ 25 V
IXTP08N100P 3.69 Littelfuse Inc. 1000 V 800mA (Tc) 10V
20Ohm @ 500mA, 10V 4V @ 50µA 11.3 nC @ 10 V ±20V 240 pF
@ 25 V
STF5N105K5 5.03 STMicro 1050 V 3A (Tc) 10V 3.5Ohm
@ 1.5A, 10V 5V @ 100µA 12.5 nC @ 10 V ±30V 210 pF @ 100 V
IXTP05N100M 6.49 Littelfuse Inc. 1000 V 700mA (Tc) 10V
17Ohm @ 375mA, 10V 4.5V @ 25µA 7.8 nC @ 10 V ±30V 260 pF
@ 25 V
STFW2N105K5 4.81 STMicro  1050 V 2A (Tc) 10V 8Ohm @
750mA, 10V 5V @ 100µA 10 nC @ 10 V 30V 115 pF @ 100 V
STF3NK100Z 5.6 STMicro 1000 V 2.5A (Tc) 10V
6Ohm @ 1.25A, 10V 4.5V @ 50µA 18 nC @ 10 V ±30V 601 pF
@ 25 V
IXTA08N120P 6.49 Littelfuse Inc. 1200 V 800mA (Tc) 10V
25Ohm @ 500mA, 10V 4.5V @ 50µA 14 nC @ 10 V ±20V 333 pF
@ 25 V
IXTP06N120P 7.6 Littelfuse Inc. 1200 V 600mA (Tc) 10V
32Ohm @ 500mA, 10V 4.5V @ 50µA 13.3 nC @ 10 V ±20V 270 pF
@ 25 V
IXFP5N100PM 12.68 Littelfuse Inc. 1000 V 2.3A (Tc) 10V
2.8Ohm @ 2.5A, 10V 6V @ 250µA 33.4 nC @ 10 V ±30V 1830
pF @ 25 V
DI2A2N100D1K 2.99 Diotec Semi 1000 V 2.2A (Tc) 10V
6.8Ohm @ 1.5A, 10V 4V @ 250µA 25 nC @ 10 V ±25V 510 pF
@ 25 V
NDFP03N150CG 3.53787 onsemi         1500 V 2.5A (Ta) 10V
10.5Ohm @ 1A, 10V - 34 nC @ 10 V ±30V 650 pF @ 30 V
2SK3746  5.54675 onsemi   1500 V 2A (Ta) 10V 13Ohm
@ 1A, 10V - 37.5 nC @ 10 V ±20V 380 pF @ 30 V
2SK2225-80-E#T2 15.85 Renesas 1500 V 2A (Ta) 15V 12Ohm
@ 1A, 15V 4V @ 1mA - ±20V 990 pF @ 10 V
IXTA05N100HV 6.54 Littelfuse Inc. 1000 V 750mA (Tc) 10V
17Ohm @ 375mA, 10V 4.5V @ 250µA 7.8 nC @ 10 V ±30V 260 pF
@ 25 V