Comparing mosfet's

[Crashr]

I am working on an abs control module, I had found some articles about replacing one of the mosfet's fixing it. The original part number for it seems to be obsolete now and mouser.com offered a substitute. I have a comparison of the two but am not familiar with the specs for these to know if the replacement would be suitable. Any help will be greatly appreciated.

http://www.mouser.com/Search/CompareProducts.aspx

[budm]

Re: Comparing mosfet's

The link to MOUSER does not show the MOSFET .
What is the sub P/N and the original P/N?

[Crashr]

Re: Comparing mosfet's

I accidentally put the wrong link on the post here are the links I meant to put up.

This is the link for the substitute
http://www.mouser.com/Search/Product...252bMExQ%3d%3d

This is the link for the obsolete part
http://www.mouser.com/ProductDetail/...tVSyHe2ddHNnis

[stj]

Re: Comparing mosfet's

piece of advice,
dont trust the crap on the screen, Mouser is often full of errors - like saying that is 250w and then saying it's 3.7w

read the actual datasheets.

[budm]

Re: Comparing mosfet's

The sub should work.
BTW, MOUSER showing is correct, the 3.7W/250W (or 3.7W/158W) rating has to do with "SOA curve for voltage derating." as shown in the notes of the datasheet.
SOA:

https://cdn.badcaps-static.com/pdfs/...4eb5480feb.pdf

https://cdn.badcaps-static.com/pdfs/...0b222215ff.pdf

[Crashr]

Re: Comparing mosfet's

Thanks for taking a look at it Bud. Looking at all those specs was a little overwhelming, I am trying to learn more about that end of the electronics but it takes a while.

[redwire]

Re: Comparing mosfet's

Look at the MOSFET avalanche rating, the old part (which has a single avalanche rating?)
This spec is really important for automotive MOSFETs and separates the men from the boys. Most are rated for a single hit (=small die) even though voltage and current specs are the same.
Pulsing inductive loads (like ABS or fuel injectors) you need to match this or your new MOSFET will die.

[Crashr]

Re: Comparing mosfet's

I'm not sure what data to compare and whether the new one should have higher specs or lower specs to to be a good replacement redwire. I looked at the avalanche data and for the new one I see (current/time and current/temperature) but for the old one all I see is (current/temperature).

[redwire]

Re: Comparing mosfet's

You did a good job of matching parameters.
I look at the package, pinout, VDS max, ID max, on-resistance, logic-level or not; VGS(th), body-diode ratings, SOA curve as some of the main ones.

The power MOSFET market is extremely competitive and some important specs are exaggerated or omitted from datasheets.
Avalanche rating is important for automotive MOSFET's:
The SUM110N05 is repetitive avalanche rated for 180mJ at <1% duty cycle, on a 0.1mH inductive load.
The SUP75N06 is single avalanche rated for 280mJ at <1% duty cycle, on a 0.1mH inductive load.

So which is the stronger part?

Power door locks are a single pulse, but ABS or Fuel injectors, they are continuously pulsing and so the repetitive avalanche rating is more important.

[Crashr]

Re: Comparing mosfet's

Thanks Redwire I really appreciate the help. I will go ahead and order the SUM110N05 then since it sounds like it will be a better part than the original. That original mosfet being a single avalanche is probably why these modules are all going bad then.

[Longbow]

Re: Comparing mosfet's

The OP has found a very good substitute in my opinion. As far as single and repetitive avalanche ratings, this type of rating is likely speculative - much of the information in these data sheets usually is.

Don't let the spec sheet stand in the way of progress with your control module. I'd be interested in hearing about your findings. A faulty FET should be easy to spot - I wouldn't bother replacing parts that don't test bad.

You might get lucky and find a typical ABS schematic but I've never seen one. We know that they contain motor(s) that are pulsed at a relative low rate, and it is a good assumption that power MOSFETS are used to drive those motors. Do ABS motors need to rotate in both directions? If so, you probably have an H-bridge drive arrangement with at least 4 FET's.

We also know that the ABS motors don't get much use, and might freeze up if the car isn't used for some time. So, faulty or frozen motors, faulty drive electronics, who knows? A final thought is that switching of inductive loads has become quite sophisticated. We don't expect the body diode of the transistor to absorb 100% of the inductive spikes any more. H-bridge drive circuitry is controlled by micros that anticipate the reverse voltage and constantly reconfigure the bridge to minimize damage to the drive parts.

Let us know.