PQFN 5X6mm Packaged N channel Power Mosfet in ClassD ...

[savu]

Hello ladies and gentlemen ...

First sorry for the faulty english ...

Today by mistake I stumbeld uppon IRFH5020 from international rectifier.
It is presented to be a very fast and powerful yet very small packaged Power Mosfet.

It's main caracteristics are:

Vds = 200V
Rds(on) = 55mOhm
Id = 43A
Qg = 36nC
Qsw = 13nC
Ciss = 2290pF

Internal Diode:

Vsd = 1.3V
Trr = 49nS
Qrr = 97nC
di/dt = 500A/uS

This data was taken from it's datasheet:
http://www.irf.com/product-info/datasheets/data/irfh5020pbf.pdf

And now the million dollar question:

Can this be used for Class D with good results?

The package beeing surface mount brings a lot of advantages concidering class D PCB requirements.

So ... what is youre opinion Diy'ers?

Best Regards,

Savu Silviu

 

[savu]

Nobody Interested ?
Well then again you can always use IRFB4227 🙁

 

[kASD]

Its a prime top choice component for Class-D, being in QFN pack its Best🙂

Provided you know how to keep it cool😉

 

[savu]

That's not a problem.

You just need some mechanical knowledge, Solid Works and a friend with a CNC to make the heat sinks.

And then you have a serious pocket size KW class D amp.

Regards,

Savu Silviu

 

[marce]

The heat is extracted through the PCB using thermal vias, and preferably a multilayer PCB with a solid ground plane. If a two laer design is used, the bottom side should have a GND copper pour directly under the thermal pad connected by thermal vias, this will improve the heatsinking capacity of the board. You can also get small surface mount heatsinks that will solder to this reverse side copper to improve things a bit.
Due to the package construction heat sinks mounted to the top of the package dont help much, due to the thermal resistance through the plastic.
The more solid copper the thermal vias are connected to the better, we use a minimum of 4 layer boards with these devices, to allow room for copper pours and room for the routes so they dont cut through any ground pours. The following links are an excellent reference for layout using QFN,s.

http://focus.ti.com.cn/cn/lit/an/sloa122/sloa122.pdf

https://www.freescale.com/files/rf_if/doc/app_note/AN3778.pdf
http://pdfserv.maxim-ic.com/en/an/AN862.pdf

 

[lumanauw]

How can we repair (remove, attach a new one) something with QFN package?

 

[savu]

Thanks Marce.

I will speak to a friend to see if he can make some copper heat sinks that can be soldered trough a PCB hole directly to the transistors pad.

I will keep you informed.

Best regards,

Savu Silviu

 

[savu]

How can we repair (remove, attach a new one) something with QFN package?

You have to use a SMD rework soldering station that has hot air for soldering SMD chips.

Best Regards,

Savu Silviu

 

[kASD]

But one has to take the Lo side mosfet into consideration while heat sinking it, because its Drain terminal will be an active switching node.

 

[marce]

My appologies, I didn't look at the device just the standard QFN (PQFN) packages, thes IR ones require slightly different layout topology.
The stuff below is directly related to the IR Power-QFN package.
I have used these and other IR mosfets in SMD packages (DirectFet being one of my favorites) for a variety of designs, SMPS, motor control,
class D etc. AN-1136 is very good. Did quite a few power supplies using these sort of packages, which was interesting, ended up getting a thermal camera
so that we could moniter where the heat was generated and where it went.
If you need any help on foot prints etc let us know (I do PCB's in Cadstar, Orcad and Allegro, mechanical is in SolidWorks)


Layout Guidlines for the actual package.
http://www.irf.com/technical-info/appnotes/an-1136.pdf

General SMD guidelines
http://www.irf.com/technical-info/appnotes/an-994.pdf


Notes for the DirectFET package, an even better choice than the Power-QFN package,
though the devices are not always suitable for some applications as the IP capacitance tends to be greater, so switching speed can be compramised.
http://www.irf.com/technical-info/appnotes/an-1059.pdf

Some HEat Sink Bunf.
http://www.irf.com/technical-info/appnotes/an-1057.pdf

 

[savu]

To workhorse:

Of course you will end up with 2 heat sinks

Regards.

 

[savu]

My appologies, I didn't look at the device just the standard QFN (PQFN) packages, thes IR ones require slightly different layout topology.
The stuff below is directly related to the IR Power-QFN package.
I have used these and other IR mosfets in SMD packages (DirectFet being one of my favorites) for a variety of designs, SMPS, motor control,
class D etc. AN-1136 is very good. Did quite a few power supplies using these sort of packages, which was interesting, ended up getting a thermal camera
so that we could moniter where the heat was generated and where it went.
If you need any help on foot prints etc let us know (I do PCB's in Cadstar, Orcad and Allegro, mechanical is in SolidWorks)


Layout Guidlines for the actual package.
http://www.irf.com/technical-info/appnotes/an-1136.pdf

General SMD guidelines
http://www.irf.com/technical-info/appnotes/an-994.pdf


Notes for the DirectFET package, an even better choice than the Power-QFN package,
though the devices are not always suitable for some applications as the IP capacitance tends to be greater, so switching speed can be compramised.
http://www.irf.com/technical-info/appnotes/an-1059.pdf

Some HEat Sink Bunf.
http://www.irf.com/technical-info/appnotes/an-1057.pdf

Thanks again,
More useful stuff.

I will contact you in case i decide do make some experiments with these kind of packages. For the moment i am working on testing ETD44 3C90 to it's limits 🙂

Best regards,

Savu Silviu

 

[kASD]

To workhorse:

Of course you will end up with 2 heat sinks

Regards.

You fail to recognize my pointer, i am not talking about 2 separate heat sinks, i am talking about EMI problem with LO-Side Mosfet Drain which will be connected to heatsink and act as antenna because it would be having no isolation.

 

[savu]

Damn it ...

You are right ... 🙁
Well ... back to the drawing board.

Thanks for the info

 

[marce]

A heatsink does not always have to be heatsink shaped, ie with fins. Quite often a plain monolithic copper coin on the reverse side can be sufficient (have a look at copper coins and RF PCB design). The aim is to reduce the thermal resistance of a bare FR4 pcb, again these devices are most often used on multilayer designs with LOTS of copper planes.
Without access to an EMC lab, it can be hard to determine how much effect a heatsink would have regarding EMC for a paticular circuit topology, as there are so many factors that come into play, switching frequency, etc etc, shape of the heatsink, how efficient will it be as an antenna.
If you wanna get into that side try:
'Electromagnetic compatability engineering' Henry W. Ott (ISBN 978-0-470-18930)

 

[savu]

You are a fountain of infomation. Thanks a milion.
If i decide to build a prototipe with this pack i will contact you for the design of the pcb.
Quality work has a price and i rather pay you cause you seem to know what you are saying 🙂

best regards

 

[marce]

Savu, I work everyday as a PCB designer and have done for 25 years, and see components like these every day. I also work closely with production departments assembling the boards, so see the problems they face, and engineers with EMC as most EMC problems can be fixed or greatly reduced by good layout..
I will willingly help you with a design, but any help would be free.

 

[savu]

Hello and thank a million Marce ...

You are a nice guy.
I has thinking of making a class d amp with these mos fets ... but i need to design a schematic first .. something with low part count. like with IRS2092, somewhere around max 1kw.

Best Regards,
Savu Silviu

 

[marce]

I've built a few speakers thanks to the guidance and help from people on this forum, and in the process enjoyed music more. So I see it just as helping in return. I have spent 25 years doing PCB's, working closeley with departments assemblying them, even ran a real Gerber photoplotter back in the early ninties, and have been through the change to lead free solder, and work with some cool stuff now, so if I can help, especially with SMD designs, its wot this sites all about. Plus a 1kw surface mount amp would be interesting, and challenging. Whether it would be possible, I dont know, but there are new and interesting surface mount power devises apearing quite often, the DirectFets being one of the more interesting. The consumer demand for mobile audio, mobile phones, and 10000W home cinema systems built in a DVD player, and of course the ECO side plus the requirements for quick reliable assembly is creating a demand for more efficient packages and circuits both electricaly and thermaly.
The down side of this is that is the requirement of more complex PCB's and quite often multilayer, which may be an issue with the limited Free PCb design software and Schematic capture packages available for hobby use.

 

[savu]

Hello Marce,

In the next 2 weeks I will probably get my hands on 50 pcs of IRFH5020 and 38 pcs of IRFH5015. So I might need your help in the recent future with the design of the PCB.

Best regards,