[sdiy] 4051 spikes

[florian anwander]

Hello,

I have setup today a simple test circuit for a batch of 4051 
(HEF14051BCP to be exact), which I received for free. While testing I 
found that all 4051 I own (not only the ones from the received batch) 
show some short feedthrough of the common signal at outputs 3 and 5 at 
not addressed times.
A picture of the scope image can be found here (signal from output 3)
http://fa.utfs.org/diy/CD4051_1.jpg
The test setup can be seen here:
http://fa.utfs.org/diy/CD4051_2.jpg
It is simply a 4069 as oscillator, a 4520 as address counter and the 4051.
One has to turn down the clock rate into the audiorange, to make this 
vanish.

Is this normal? Is it caused by the breadboarding setup?

Thanks for any insight.

Florian