electronic part question

[radio freak]

Hello ,
I have two questions to ask.

1.Are IRFZ44 and IRFZ44N two different parts??? does any one have datasheets for IRFZ44.
2.How do you determine how much current a MOSFET can handle in an esc.
I mean, according to IRFZ44N's datasheet, it can handle 49 amps but this particular page on stefan's website[http://www.stefanv.com/electronics/escboth.html]
shows a table in which current handling capacities of different mosfets are given and it states that IRFZ44N can handle only 8 amps.????
thanks.

[MikeDD]

This site shows both. Subcription required for data sheets.

http://www.chipdocs.com/datasheets/datasheet-pdf/International-Rectifier/IRFZ44.html

[fredhs]

Hi,

sorry, I am not sure about the postfix "N" in this specific case. You may want to try the following site for freely available datasheets:

http://www.datasheetcatalog.com/datasheets_pdf/I/R/F/Z/IRFZ44.shtml

Regards,

Fred

[Gary Warner]

IRF has both on their site:

IRFZ44 (http://www.irf.com/product-info/datasheets/data/irfz44.pdf)
IRFZ44N (http://www.irf.com/product-info/datasheets/data/irfz44n.pdf)

I think the only real difference is with the die shape & process (internal structure). They effectively are the same. The IRFZ44 has long been a workhorse FET in ESC's, not just in model motors. The only draw back about this FET is that it's resistance at a 5V gate voltage is a bit high. To use it anywhere close to it's limits the gate has to have a clean 10V gate drive. Also, as heat increases it's limits will reduce, as with any FET.

When I was designing ESC's 15 years ago, I'd use 44's at 10 amps each. For example, I'd use 6 of them to control 60 amps because of limited heat sinking and 5 volt gate drive. At the time, logic level 44's were too expensive and charge-pumping to 10V was a pain. Today's approaches to ESC design make my old ESC's look like a horse drawn wagon would to a modern car.

[radio freak]

So can I use an IRFZ44 and IRFZ44N together in an esc, I mean you can use only the same mosfets in parallel to increase the current capacity. since the two fet's are similar can they be used together in parallel on the same esc??
ihanks!

[AndyKunz]

NO! You don't want to mix different types of FETs if you're connecting them in parallel. In fact, you want to keep them from the same die lot if possible (what I do for the ones I manufacture). At my daytime employer for some products we actually test the FETs for matching before putting them onto the boards (it's called "binning" the parts).

Andy

[RX5]

the "N" part is much better..

[Pgarrett]

Radio freak,
What you really want is the low gate voltage threshold Mosfet version
such as the IRFLZ44...Gate threshold (lowest Gate-voltage that will operated the Mosfet) of 5 volts or less...handles up to 35 to 50 Amps. Load.--
You can saw off the heat-sink Tab if you want to make it lighter....
I have used lots of these in ESC circuits..
I can send you some of those free to play with.
Contact: Paul at
Budtronics@aol.com

[jeffs555]

Paul,
Couldn't find an IRFLZ44 at irf.com. Did you possibly mean IRLZ44?

Radio Freak,
The current rating published on most mosfet data sheets is usually for ambient temperature of 25 degC with a nearly perfect heat sink. When used on a hot day outside with no heat sink, they must be derated greatly.

Jeff