[sdiy] DG409 blues

[ASSI]

On Saturday 06 February 2010, David G. Dixon wrote:
> Does anybody have any experience with or insight into the DG408/9
> analog multiplexers?


Which manufacturer, there are several?  The Intersil parts at least 
should tolerate the full voltage range from V- to V+ on their inputs, 
but the switching threshold are always TTL compatible regardless of 
signal swing.

What you are experiencing might indeed be a switching glitch, at such 
a high input signal swing the decoder could see several transitions if 
the termination is not good enough or the input slope is slow and/or 
data dependent.  If the ringing on the inputs is bad enough you could 
even get the protection diodes into conduction, which certainly should 
not happen when you want clean analog signals.  You could either use a 
gray code or disable the switch during code changes to avoid glitches 
or just limit the data signals to around 3V and see if that helps.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Factory and User Sound Singles for Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#WaldorfSounds