[sdiy]RE: Re: [sdiy] Overdriving 4069UB

[rdrake]

René Schmitz has a VCO based on the 4069 (http://www.uni-bonn.de/~uzs159/vco4069.html); he mentions that the chip runs hot at 15 volts but apparently doesn't burn up.  I've got 2 running at 12 volts and have never noticed any heat issue at all.

bbob

>----- ------- Original Message ------- -----
>From: seb at burnit.co.uk
>To: music.maker at gte.net
>Sent: Tue, 03 Jan 2006 00:09:53
>
>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