Page 1 of 1


PostPosted: Fri Dec 07, 2007 9:17 pm
by kf1z
Looks like the supply of FQA11N90 FETs will be running dry soon...

Mouser has NONE

Digikey has NONE

Newark has 500, and won't be restocking...

May indeed be time to look for a new "big Bang for the Buck" transistor.

PostPosted: Fri Dec 07, 2007 9:34 pm
by frank carcia
It would be nice to find a new high voltage FET with lower RDS on with the same or lower internal C.........but then my first rig back in the 80s used IRF250s.....Then there was WA1KNX who actually had someting on for a while then. I settled on the IRF840 in the 90s then Steve found the 11N90s around 2001 or so. it is about time.
I've yet to blow a 11n90. I blew every IRF250 after a while, Blew a few IRF840s. It is getting a lot easier to do this stuff. Let's hope they keep making a package we can use.

PostPosted: Fri Dec 07, 2007 10:13 pm
by kf1z
Mouser lists the STW12NK90Z as a "cross reference" device.

The Rds is lower, ( .72 to .88 )

The Ciss is a smidge higher (3500pf)

Same voltage and current....

May be an ok sub...

Cheaper too....

Mouser's price was $3.04 (or so) in low quantities....

I'm sure there'll be FQA11N90 floating around for a while...

There's a guy on ebay selling them for $4.00 each

I'm sure there's plenty of other devices that will do just dandy......



PostPosted: Sun Jan 06, 2008 6:11 am
by W2WAS
Fairchild is still listing it as in "Full Production".


PostPosted: Sun Jan 06, 2008 10:07 am
by kf1z
They may list it as "full production", but they don't have any......
And neither do most of their distributors.

What I did notice though is that they have changed the datasheet (updated). Sept, 2007

It could well be that they are waiting for the distributor stock to completely expire...
And that they are now making the part RoHs compliant....

Then maybe the distributors will re-stock.

(Though Newark has some that are lead-free... and say they won't get more....)

Time will tell I guess. !!


PostPosted: Tue Mar 02, 2010 9:34 pm
by steve_qix
The FQA11N90 may indeed be out of production. There is a "replacement" available from Fairchild - this is the FQA11N90C. The "C" version uses a very slightly smaller die - and the R D-S on is ever so slightly higher, and the device will handle .4 amperes less current (an even 11 amperes).

So, this is probably the closest sub available. The gate C and reverse transfer capacitance are both a bit lower. It's probably a good 1 for 1 substitution, since we are not pushing the current anywhere near the danger point with the present designs.

We *CAN* if we want, get the FQA11N90 (there are thousands of them out there). If we want to buy in quantity 1000, we can get them for $2.50 each or so (maybe a bit less). I'll go in with folks if they want to form an order, but I don't personally need 1000 devices, nor do I have the money !

The FQA11N90C can be had for less money. I'll split up an order of those also if anyone wants.

So far, the 11n90 has been a very good part - low transfer capacitances make it work very nicely up to 40 meters with digital drive.




PostPosted: Wed Mar 03, 2010 8:08 am
by kf1z
The "new" part number is FQA11N90_F109

Supposedly $2.35 each for a quantity of 295 pcs. (lead time of 28weeks!!)
Through Mouser.

Newark says $1.99 each qty 450 pcs.... lead time 199 days.

I have some fqa11n90C if you want to put them to the test Steve....
I used them in my first 2 renditions , and only blew up 2 of them :)
Think that was metal sliver under the sil-pad though.

Seems like the FQA10N80 shouldn't be too far behind.... ?


PostPosted: Wed Mar 03, 2010 8:21 am
by steve_qix
I have not called Fairchild to find out the production status. They do say they are in full production of the parts on their web site. There are 10s of thousands of FQA11N90s available right now. They are just out of the country, but we *can* get them, but not in quantity 1. There are at least 2500 of them here, in stock, in the US, - available for about $2.50 each in quantity 1000. Who knows? Maybe in quantity 100, we can get them for $2.70 each or something like that.

From what I've been able to determine, distributors are not stocking anything unless it is guaranteed to move quickly. This problem is showing up with many other parts, not just these parts.

When I talked with Fairchild a few years ago about the FQA11N90, the guy I spoke with said Korea and China were taking every part Fairchild could build. The only reason we could get them here at all is that a couple of distributors placed orders and then waited 26 weeks for stock. When I placed the initial order for the parts, I had to wait more than 3 months, and had to order 450 parts minimum (which is how many I ordered).

Anyway, there do appear to be quite a few of them out there.... just not in franchise.