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Old 19th September 2011, 05:29 PM   #1
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Default Parallel Lateral FETs

How important is matching of Lateral FETs?

Planning on using 3 pairs of Lateral FETs for output stage without source resistors, since they really dont do much for current sharing.

There should in theory be no stability issues with several parallel Laterals, but what about the real world?

I'm only talking about stability here, and not about whatever small THD imporvemtn one might get with matched Laterals.

But if we talk about THD as well, does matching really improve it that much and if so is it audible?
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Old 19th September 2011, 06:32 PM   #2
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Quote:
Originally Posted by Neutrality View Post
How important is matching of Lateral FETs?

Planning on using 3 pairs of Lateral FETs for output stage without source resistors, since they really dont do much for current sharing.

There should in theory be no stability issues with several parallel Laterals, but what about the real world?

I'm only talking about stability here, and not about whatever small THD imporvemtn one might get with matched Laterals.

But if we talk about THD as well, does matching really improve it that much and if so is it audible?
I`m technically not qualified enough about discussing merits (or not) of paralleling lateral FETs without source resistors - but I know it`s doable.

Here an ("real world") example:
http://www.albs.de/img/dac_600_gross.jpg
QUAD-MOS 600 Mosfet-Verstärkermodul

To use Laterals without any source resistors I think (tight) matching is required.
Here a description about how to match:
Mosfet Matching
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Old 20th September 2011, 03:56 AM   #3
Tajzmaj is offline Tajzmaj  Slovenia
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Best results......go with closely matched fets and source resistors as well. Othewise you will get more heat and more distortion...
Take a look at DH500 Hafler amp......
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