Hello Everybody!

The project is a 3 foot long 48 common anode LED RGB lightbar controlled by software PWM using a PIC MCU.

Here is the current PCB layout...

.48 inches wide and 12 inches long.
http://img245.imageshack.us/img245/7070/ss20090603175454.png


Do I need a grounding plan on the PCB to prevent broadcasting interference to other electronic devices?

Another concern is the trace widths... each color will consume a max .96 amps @ 5v and the traces are 0.039 wide... is this enough width? How long can I run the trace with out resistance or voltage drop effecting the LEDs output? Note: the positive is slightly wider and is doubled. (one trace on top and one on bottom)

Thanks

-Prop-

 

what freq is your pwm. it doesnt need to be high for led drive. i dont think you need a ground plane. however, if its double sided board then use the underside for ground (less etching, etc).

many trace calculators out there. here's a couple http://circuitcalculator.com/wordpress/2006/01/31/pcb-trace-width-calculator/

http://www.referencedesigner.com/cal/cal_06.php

 

Well, I am still unsure on the PWM frequency calculations. 25000 interrupts per second divided by 255 (resolution) = 100ish Hz.

 

PWM is independent of frequency.

@100Hz i dont think you'll see much rfi.