MAT-02 and MAT-04

Tim Ressel Tim_R1 at verifone.com
Wed Mar 15 18:51:12 CET 2000


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




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