4046 PLL appnote; was Re: 4046 VCO experiment

[Donald Johnson]

Hairy Harry wrote:
> Send reply to:  	harrybissell at prodigy.net
> From:           	"Hairy Harry" <paia2720 at hotmail.com>
> To:             	czech at Micronas.Com, chordman at earthlink.net
> Copies to:      	synth-diy at node12b53.a2000.nl
> Subject:        	Re: 4046 VCO experiment
> Date sent:      	Thu, 17 Aug 2000 16:50:39 GMT
> 
> Hi everybody:
> 
> Two thoughts
> 
> 1) Check out the internal VCO schematic of the 4046... its in
> ICAN-6101. Scott's circuit is still activating the CMOS Current
> Mirror... so basically the operation is still the same.

 I couldn't find any RCA .pdf application notes dated 1972. ;)
 TI has it here, with the same name:
   http://www.ti.com/sc/docs/psheets/abstract/apps/scha002.htm
 
> 2) Think about stealing the archetecture, but built with
> discrete CMOS chips... maybe 4007 for the capacitor reset
> section, and 4049UB for the rest... but absolute symmetry is
> required... each branch must be formed from devices in the same
> package. You need symmetry along the vertical axis...
> (matched right/left hand). Then... replace the current mirror with a
> discrete temp compensated current source.
> 
> H^)  harry

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