Output PCB design thoughts

[Krisfr]

I am posting a sketch of a output section of a PCB design using Surface mount resistors for the emitter each of the resistors is one ohm so the sum is .5 ohm without the inductance of the wire wound inherit in type of this low ohmage and high wattage.

The circle is a cap of about 8 mm

Constructive comments are welcome. SMILE

[nigelwright7557]

Loads of ground copper and powerplanes if possible.

It costs nothing to add copper just time.

[Krisfr]

Would it be sane to do this in a 4 layer board? with one layer solid Ground and another Solid Power split between the rails?

[nigelwright7557]

Originally Posted by Krisfr

Would it be sane to do this in a 4 layer board? with one layer solid Ground and another Solid Power split between the rails?

I usually get away with lots of copper on the power supplies and the output signal.

I wouldnt of thought it was worth the extra cost of going to 4 layers.

I do my best with two layers.

[AndrewT]

the big gap between the two rows of output devices demand a very tall heatsink. Gets big and bulky and heavy compared to a lower profile where all the devices are close spaced.

[thunderpld]

Take a pencil and divide the mounting space of the heat sink evenly according to the number of output devices.Find the center of each rectangle,that should be the ideal mounting place for each transistor.And don't get too worked up about resistor inductance,i am sure that its very low.