[sdiy] Some thoughts about ladder filter circuit

[Jim Patchell]

Yes they can...I can get about 7 octaves at +/- 1 cent deviation.  A 
MAT04 I can get about 8 octaves.

I use the extra transistors to make a band gap temp sensor that I use to 
compensate for temperature...No heaters, no tempcos...

http://www.noniandjim.com/Jim/synthmodules/100-1007.pdf


David G. Dixon wrote:
> General question: Are these arrays suitable for VCO expo circuits?  They're
> certainly cheaper than super-matched pairs and quads!
> 
> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of George Hearn
> Sent: Friday, December 12, 2008 7:20 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: RE: [sdiy] Some thoughts about ladder filter circuit
> 
> The LM3046 from National semiconductor is better than the CA3046 from
> Harris/Intersil in terms of transistor matching (Vbe match).  I've carried
> out a lot of tests with this chip as it's central to many of my synth
> circuits.  They quote a Vbe match of 1mV or better for the LM3046 I think
> and 5mV or better for the CA3046.  In the CA3046 only the diff pair is
> matched to 1mV Vbe wheras the LM3046 they are all matched to 1mv Vbe.
> However, in practice the LM3046 transistors are vbe matched to much better
> than 1mV making them really good for all sorts of circuits for synth diyers
> ready to get down and dirty with discrete designs!  RS has the SMD part for
> 20p in 100pcs.  George
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
> 

-- 
----------------------------------------------
Visit http://www.noniandjim.com
SDIY: http://www.noniandjim.com/Jim/index.html
----------------------------------------------