[sdiy] Why is TB-303 IC6 connected to both digital and analogvoltage rails?

Gordon JC Pearce gordonjcp at gjcp.net
Sun Dec 15 00:51:26 CET 2013


On Sat, Dec 14, 2013 at 08:40:43PM -0000, Colin f wrote:
>  
> > Right, that would explain an input to a trigger, but why is 
> > 5.333 connected to Vdd? As well as 6V?
> 
> The 5.33V supply controls the DAC scaling.
> It's effectively the reference voltage for the R-2R DAC built around the
> latch.
> 
> Cheers,
> Colin f

Not only that, but IC6 also forms the tempo oscillator, so powering it off 5.333V ensures that it has a regulated supply unlike the rest of the logic which comes off the 6V rail.

-- 
Gordonjcp MM0YEQ




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