MAT-02 and MAT-04

[harrybissell at prodigy.net]

I've played with a scheme to use the heater of the
LM399 as a passive heater for a tranny such as the
MAT-02... It did not work as well as a stabilized 3046 but it is very simple, and does not have any electrical
connection to the MAT-02 trannies...

E-mail me if you want to see the graphs... I posted them
last year...

H^)  harry


 ---- On Mar 15 Tim Ressel <Tim_R1 at verifone.com> wrote: 
> Jim,
> 
> I am getting ready to try a scheme where two of the transistors in a MAT-04
> would be for a expo convertor, and the other two would be for a heater, with one
> as a sensor and the other as the heating element. The current specs are way down
> from the CA3046, so the heating will be less. I may have to use an external
> resistor for heat, and perhaps go to switching scheme instead of linear control.
> 
> 
> Tim Ressel--Compliance Engineer
> Hewlett-Packard
> Verifone Division
> 916-630-2541  
> tim_r1 at verifone.com                     
> 
> 
> 
> -----Original Message-----
> From: Jim Patchell [mailto:patchell at teletrac.com]
> Sent: Wednesday, March 15, 2000 9:01 AM
> To: synth-diy at node12b53.a2000.nl
> Subject: MAT-02 and MAT-04
> 
> 
> 
>     I am getting ready to make a bulk purchase of transistors for
> exponential converters.  Here is the problem:
> 
>     As many of you may or may not know, the MAT-02 costs about $8.  The
> MAT-04 costs about $4.  When you consisder that the MAT-04 has four vs
> two transistors for the MAT-02, the MAT-04 is 1/4 the cost.
> 
>     You don't get something for nothing so here is the rub:
> 
>     The MAT-02 has slightly better specs (Bulk resistance is about 0.1
> ohm less), which is probably not "real" significant.  The other
> consideration is crosstalk.  Since the MAT-04 would likely be used to do
> two VCO's, has anybody got any experience in unwanted syncing between
> oscilators using the same transistor array to do the exp function for
> both oscilators?
> 
>     If there are any other good arguments for or against a dual vs. quad
> transistor array in this application, I would like to hear them.
> 
>     I do plan to make whichever part I get availiable to SYNTH-DIY
> people at cost when I get them.
> 
>     Thanks for any help.
> 
>     -Jim
>