Using IRFZ44 in place of a IRFP044

Nicwix · 13th July 2002, 09:01 AM

I can obtain the IRFZ44 for A$3.00 (possibly less in quantity) whereas the IRFP044 is $7.85 in small quantities.

The IRFZ44 seems to be pretty much the same device in a better package TO-247 instead of TO220.

Key spec.s are as follows:

IRFP044 / IRFZ44

VDSS = 60V (same)
RDS(on) = 0.28 (same)
ID = 57 / 50A
Power Dis. 180 / 150W
Thermal Res. - Case to Sink: 0.24 / 0.5 C/W
gfs: 17 / 15S
td(on): 19 / 14ns
td(off): 55 / 45ns
Ciss: 2500 / 1900pF

Any views on this and are there any other critical specifications to consider?

Nix

nickgreek · 13th July 2002, 09:12 AM

Prise IRFP044
1.35 euro
in http://www.reichelt.de/

AudioFreak · 13th July 2002, 11:33 AM

Use the IRFP044's... You'll probably find it works out cheaper to import these devices from arrow or digikey in america.

Nicwix · 13th July 2002, 11:51 PM

Minor correction to above

"The IRFZ44 seems to be pretty much the same device in a better package TO-247 instead of TO220."

should read:

"The IRFZ44 seems to be pretty much the same device except that the IRFP044 has a better package (TO-247) and hence higher power rating than the IRFZ44 (TO220 package). OTOH the IRFZ44 is slightly faster."

I appreciate the advice above - but can anyone tell me why the IRFP044 is preferred (given the power of either is ample) - what other specs are important when choosing a MOSFET?

Nix

AudioFreak · 14th July 2002, 04:55 AM

VDSS = 60V .... rail to rail voltage should be less than this
RDS(on) = 0.28 (same) .... meaningless when building analogue amplifiers
ID = 57 / 50A .... high is better
Power Dis. 180 / 150W .... this is a function of die size and hence also Ciss as well as package type .... for a given power rating for the amp output stage we try to minimize total culmative Ciss
Thermal Res. - Case to Sink: 0.24 / 0.5 C/W .... you'll be able to run the bias high with the 044's for a given Junction temp
gfs: 17 / 15S .... higher transconductance is preferred
td(on): 19 / 14ns .... Assuming we set the XA to 50% and operate it below cutoff which is what we normally do then the mosfets dont turn on or off at any time during the waveform.
td(off): 55 / 45ns .... same as for td(on)
Ciss: 2500 / 1900pF .... determines the number of devices that can be placed in parallelled for a given high frequency rolloff.

Hope all that helps.

Nicwix · 18th July 2002, 11:16 PM

AudioFreak

Thanks for the detailed reply - I understand all your points.

What other specs are important?

I also emailed you re your matched IRFP240 sale.

Nic

Nelson Pass · 18th July 2002, 11:31 PM

I haven't tried the Z44, so I couldn't say, but the
higher transcondctance and current rating is going to
make for a slightly different sound. Like the IRF150 or
250, it will probably tend to have better performance
on the bottom, but may be a bit darker on the top.

You might like this better, maybe not. Try it.

13th July 2002, 09:01 AM	#1
Nicwix diyAudio Member Join Date: Dec 2001 Location: Sydney, Australia	Using IRFZ44 in place of a IRFP044 I can obtain the IRFZ44 for A$3.00 (possibly less in quantity) whereas the IRFP044 is $7.85 in small quantities. The IRFZ44 seems to be pretty much the same device in a better package TO-247 instead of TO220. Key spec.s are as follows: IRFP044 / IRFZ44 VDSS = 60V (same) RDS(on) = 0.28 (same) ID = 57 / 50A Power Dis. 180 / 150W Thermal Res. - Case to Sink: 0.24 / 0.5 C/W gfs: 17 / 15S td(on): 19 / 14ns td(off): 55 / 45ns Ciss: 2500 / 1900pF Any views on this and are there any other critical specifications to consider? Nix

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13th July 2002, 09:12 AM	#2
nickgreek diyAudio Member Join Date: Jun 2002 Location: Germany	Prise IRFP044 1.35 euro in http://www.reichelt.de/

13th July 2002, 11:33 AM	#3
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	Use the IRFP044's... You'll probably find it works out cheaper to import these devices from arrow or digikey in america.

13th July 2002, 11:51 PM	#4
Nicwix diyAudio Member Join Date: Dec 2001 Location: Sydney, Australia	Minor correction to above "The IRFZ44 seems to be pretty much the same device in a better package TO-247 instead of TO220." should read: "The IRFZ44 seems to be pretty much the same device except that the IRFP044 has a better package (TO-247) and hence higher power rating than the IRFZ44 (TO220 package). OTOH the IRFZ44 is slightly faster." I appreciate the advice above - but can anyone tell me why the IRFP044 is preferred (given the power of either is ample) - what other specs are important when choosing a MOSFET? Nix

14th July 2002, 04:55 AM	#5
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	VDSS = 60V .... rail to rail voltage should be less than this RDS(on) = 0.28 (same) .... meaningless when building analogue amplifiers ID = 57 / 50A .... high is better Power Dis. 180 / 150W .... this is a function of die size and hence also Ciss as well as package type .... for a given power rating for the amp output stage we try to minimize total culmative Ciss Thermal Res. - Case to Sink: 0.24 / 0.5 C/W .... you'll be able to run the bias high with the 044's for a given Junction temp gfs: 17 / 15S .... higher transconductance is preferred td(on): 19 / 14ns .... Assuming we set the XA to 50% and operate it below cutoff which is what we normally do then the mosfets dont turn on or off at any time during the waveform. td(off): 55 / 45ns .... same as for td(on) Ciss: 2500 / 1900pF .... determines the number of devices that can be placed in parallelled for a given high frequency rolloff. Hope all that helps.

18th July 2002, 11:16 PM	#6
Nicwix diyAudio Member Join Date: Dec 2001 Location: Sydney, Australia	AudioFreak Thanks for the detailed reply - I understand all your points. What other specs are important? I also emailed you re your matched IRFP240 sale. Nic

18th July 2002, 11:31 PM	#7
Nelson Pass The one and only Join Date: Mar 2001	I haven't tried the Z44, so I couldn't say, but the higher transcondctance and current rating is going to make for a slightly different sound. Like the IRF150 or 250, it will probably tend to have better performance on the bottom, but may be a bit darker on the top. You might like this better, maybe not. Try it.

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