Almost new Linear Fet - Page 2

carpenter · 25th October 2009, 01:49 PM

I meant, the Ciss is ten time higher than what we normally see in a mosfet. This makes for poor treble, if I recall correctly.

Samuel Jayaraj · 25th October 2009, 02:32 PM

Quote:

Originally Posted by carpenter

I meant, the Ciss is ten time higher than what we normally see in a mosfet. This makes for poor treble, if I recall correctly.

And for more driving current from the previous stage!

tiefbassuebertr · 25th October 2009, 03:23 PM

I din't know, what you mean with the keyword "Normal MOSFETs"

as I compare the values CISS COSS and CRSS I read in the datasheets
(by VGS=0V, VDS=20V and f=1MHz) follow pF values
http://ixdev.ixys.com/DataSheet/DS10...10N20L2%29.pdf
http://www.irf.com/product-info/data...ta/irf540n.pdf
http://www.datasheetcatalog.org/data...onics/9387.pdf
IRF540-D Datasheet pdf - TMOS E-FET Energie Fangen Effekt-Transistor N-FÃ¼hrung Verbesserung-Modus Silikon-Gatter auf - ON Semiconductor or
http://www.datasheetcatalog.org/data...r/IRF540-D.PDF
2SK134 datasheet pdf datenblatt - Hitachi Semiconductor - LOW FREQUENCY POWER AMPLIFIER ::: ALLDATASHEET :::
http://documentation.renesas.com/eng..._2sk2220ds.pdf
http://www.semelab.com/pdf/magnatec/BUZ900P.pdf

1) IXYS IXTX110N20L2: 23/2160/320 (lowest CISS what I have ever see regarded the other parameters, for very low driver charge current)
2a) IRF IRF540: 1960/250/40 (VGS = 0V, VDS = 25V)
2b) ST IRF540: 870/125/250 (VGS = 0V, VDS = 25V)
2c) ON IRF540 : 1460/390/320
3) Hitachi 2SK134: 600/350/10 (but VGS 5V/VDS 10V)
4) Renesas 2SK2221: 600/800/8 (also VGS 5V/VDS 10V)
5) Semelab BUZ900 500/300/10 (VGS not mentioned, VDS 10V)

relder · 25th October 2009, 04:34 PM

Quote:

Originally Posted by tiefbassuebertr

I din't know, what you mean with the keyword "Normal MOSFETs"

as I compare the values CISS COSS and CRSS I read in the datasheets
(by VGS=0V, VDS=20V and f=1MHz) follow pF values
http://ixdev.ixys.com/DataSheet/DS10...10N20L2%29.pdf
http://www.irf.com/product-info/data...ta/irf540n.pdf
http://www.datasheetcatalog.org/data...onics/9387.pdf
IRF540-D Datasheet pdf - TMOS E-FET Energie Fangen Effekt-Transistor N-FÃ¼hrung Verbesserung-Modus Silikon-Gatter auf - ON Semiconductor or
http://www.datasheetcatalog.org/data...r/IRF540-D.PDF
2SK134 datasheet pdf datenblatt - Hitachi Semiconductor - LOW FREQUENCY POWER AMPLIFIER ::: ALLDATASHEET :::
http://documentation.renesas.com/eng..._2sk2220ds.pdf
http://www.semelab.com/pdf/magnatec/BUZ900P.pdf

1) IXYS IXTX110N20L2: 23/2160/320 (lowest CISS what I have ever see regarded the other parameters, for very low driver charge current)
2a) IRF IRF540: 1960/250/40 (VGS = 0V, VDS = 25V)
2b) ST IRF540: 870/125/250 (VGS = 0V, VDS = 25V)
2c) ON IRF540 : 1460/390/320
3) Hitachi 2SK134: 600/350/10 (but VGS 5V/VDS 10V)
4) Renesas 2SK2221: 600/800/8 (also VGS 5V/VDS 10V)
5) Semelab BUZ900 500/300/10 (VGS not mentioned, VDS 10V)

You're mixing picoFarads with nanoFarads, the 23nf IXYS part == 23000picoFarad which is of course more than the IRF540's 1960picoFarad

flg · 25th October 2009, 05:34 PM

Smaller resistors are necessary to deal with the higher C values so as not to cause a reduction in high frequency response. More importantly might be the non-linear C increase as the device D-S voltage lowers. But in the case of the IXTK110N20L2 that happens well bellow 5V. Uniquely good compared to MOSFETs we typically use.

Melon Head · 09:13 PM

what about this one http://ixdev.ixys.com/DataSheet/9ad7...3a9ba842d9.pdf

Or what about this one http://ixdev.ixys.com/DataSheet/0792...410e7fb8a2.pdf

tiefbassuebertr · 10:57 PM

Quote:

Originally Posted by relder

You're mixing picoFarads with nanoFarads, the 23nf IXYS part == 23000picoFarad which is of course more than the IRF540's 1960picoFarad

Yes, you are right, that was a mistake from me. Amazingly is, that also the use for linear amplifier was recommended in the datasheet from IXYS. So only at one stage amplifiers such "ZEN", "First Watt" and "Circlotron" this MOSFET work without trouble, because in this topologies the behaivour of capacity is like low pass filter

25th October 2009, 01:49 PM	#11
carpenter Paper mache horn fabricator diyAudio Member Join Date: Mar 2002 Location: Oregon City, Oregon	I meant, the Ciss is ten time higher than what we normally see in a mosfet. This makes for poor treble, if I recall correctly. __________________ I enjoy audio so much that I constructed a web site. I share my ideas at: www.inlowsound.com

25th October 2009, 03:23 PM	#13
tiefbassuebertr diyAudio Member Join Date: Jul 2005 Location: D-55629 Schwarzerden	CISS ten times higher compare to normal MOSFETs I din't know, what you mean with the keyword "Normal MOSFETs" as I compare the values CISS COSS and CRSS I read in the datasheets (by VGS=0V, VDS=20V and f=1MHz) follow pF values http://ixdev.ixys.com/DataSheet/DS10...10N20L2%29.pdf http://www.irf.com/product-info/data...ta/irf540n.pdf http://www.datasheetcatalog.org/data...onics/9387.pdf IRF540-D Datasheet pdf - TMOS E-FET Energie Fangen Effekt-Transistor N-FÃ¼hrung Verbesserung-Modus Silikon-Gatter auf - ON Semiconductor or http://www.datasheetcatalog.org/data...r/IRF540-D.PDF 2SK134 datasheet pdf datenblatt - Hitachi Semiconductor - LOW FREQUENCY POWER AMPLIFIER ::: ALLDATASHEET ::: http://documentation.renesas.com/eng..._2sk2220ds.pdf http://www.semelab.com/pdf/magnatec/BUZ900P.pdf 1) IXYS IXTX110N20L2: 23/2160/320 (lowest CISS what I have ever see regarded the other parameters, for very low driver charge current) 2a) IRF IRF540: 1960/250/40 (VGS = 0V, VDS = 25V) 2b) ST IRF540: 870/125/250 (VGS = 0V, VDS = 25V) 2c) ON IRF540 : 1460/390/320 3) Hitachi 2SK134: 600/350/10 (but VGS 5V/VDS 10V) 4) Renesas 2SK2221: 600/800/8 (also VGS 5V/VDS 10V) 5) Semelab BUZ900 500/300/10 (VGS not mentioned, VDS 10V)

25th October 2009, 05:34 PM	#15
flg diyAudio Member Join Date: Jul 2005 Location: North East	Smaller resistors are necessary to deal with the higher C values so as not to cause a reduction in high frequency response. More importantly might be the non-linear C increase as the device D-S voltage lowers. But in the case of the IXTK110N20L2 that happens well bellow 5V. Uniquely good compared to MOSFETs we typically use. __________________ “Be who you are and say what you feel because those who mind don't matter and those who matter don't mind.” Dr. Seuss

25th October 2009, 09:10 PM	#16
Melon Head Formerly Thanh1973 Join Date: Nov 2006	what about this one http://ixdev.ixys.com/DataSheet/9ad7...3a9ba842d9.pdf Or what about this one http://ixdev.ixys.com/DataSheet/0792...410e7fb8a2.pdf __________________ "No, this sucker's electrical, but I need a nuclear reaction to generate the 1.21 gigawatts of electricity I need." Last edited by Melon Head; 25th October 2009 at 09:13 PM.

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