[sdiy] Overdriving 4069UB

[Seb Francis]

Harry Bissell Jr wrote:

> One other problem might be that you are using two stages
> in linear mode. These will get hotter than normal. Make sure it
> does not run TOO hot. Its probably Ok.
>
> The resistors do not limit this power... it flows from N to P channel 
> device
> which are both 'half on'. It will be worst with no signal input
>
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?

Seb