[sdiy] Overdriving 4069UB

[Seb Francis]

Scott Gravenhorst wrote:

>>>      
>>>
>>Yeah I did notice it uses a lot of current .. about 28mA with no 
>>signal.  This could be a problem because I plan to use the other 3 
>>buffers for a 2nd channel of distortion.  When 28mA was measured the 
>>other 3 inputs were hooked to 0V, so I'd imagine it would take more like 
>>56mA when using all 6 buffers.  This equates to 840mW at 15V (the 
>>absolute maximum is dissipation on the datasheet is 700mW).
>>
>>Any way round this?  A heatsink perhaps?
>>    
>>
>
>Maybe lower the supply voltage.  +/- 5V ?
>
>If you must have 15 volts, I would do this with either 2 x 4007 or 2 x
>4069UB.  I've done linear stuff with a 4069UB, but not using all six
>inverters that way.  I made a dual triangle LFO with a 4069UB and it got
>warm, running at 8V.  Two of the inverters were integrators, 4 were used
>to make two schmitt triggers so not all the amps were linear.
>  
>
I'm leaning towards the idea of using 2 x 4069s.  I'd prefer to stay at 
15 volts because that's what power I have available (and actually I 
think even at 10V, using 6 inverters in linear mode will be pushing it).

Anyway, I was a bit worried about cross-talk when using the same device 
for 2 channels, so it would also be better from this point of view just 
spend the extra 20p and use 2 :-)

Seb