[Coco] What happens if a slow 6809EP is used....

jdaggett at gate.net jdaggett at gate.net
Tue Jan 19 16:22:34 EST 2010


On 19 Jan 2010 at 6:42, Mike Pepe wrote:

> It may, I've never tested that, but as an NMOS device the 6809's power
> dissipation doesn't change much with operating frequency as, say, a CMOS
> device where the power-to-frequency relationship is far more linear.

Oh yes it does. Swithcing current is determined by the change in voltage versus the change 
in time. This does not matter if it is NMOS, CMOS biCMOS or bipolar. NMOS switches faster 
than CMOS. HCMOS will switch faster than NMOS. 

Switching currents are also affected by load capacitances placed onteh output of the gate. 
Greater capacitances will also affect rise and fall times within the chip. 

james



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