MAT-04/CA3046 Characterization

[Martin Czech]

I think it is dangerous to rely on transistor matching through
different places from a wafer, or even lots.
I.e. the voltage versus temperature could be different for each individual
transistor. This means that the servo loop must be calibrated for each 
individual sensor, otherwise the chip temperature is too low or too hot.


m.c.

:::From: Tim Ressel <Tim_R1 at verifone.com>
:::To: synth-diy at node12b53.a2000.nl
:::Subject: MAT-04/CA3046 Characterization
:::Date: Tue, 6 Jun 2000 16:07:22 -0700 
:::
:::Yo,
:::
:::I just completed the characterization run. Here are the results:
:::
:::Chamber	MAT-04	MAT-04	CA3046
:::Temp		Temp		Voltage	Voltage
:::39.9		39.9		.5451		.6892
:::45.0		44.8		.5338		.6803
:::49.9		49.6		.5227		.6715
:::55.0		54.7		.5111		.6624
:::60.0		59.5		.4999		.6535
:::
:::PS Voltage: 9.98V
:::Bias resistor: 10.0K 1%
:::
:::As you can see, the MAT-04 voltage is way different than the CA3046. This 
info
:::is useful for setting the bridge voltage on the AN-299 heater scheme. For
:::example, if you wanted the MAT-04 to run at 40C, you would select a voltage
:::divider pair to yield .5451 volts, or close to it at least. The stock circuit
:::yielded 0.6273V. 
:::
:::Next I am going to run the AN299 circuit with the MAT-04 over temperature to 
see
:::how it does. Unfortunately, when I rigged the circuit in the chamber it 
didn't
:::work. I somehow blew the MAT-04. The spare is working okay. After I glue the
:::thermocouple to the back of the new MAT-04 I will begin the next run.
:::
:::Tim Ressel--Compliance Engineer
:::Hewlett-Packard
:::Verifone Division
:::916-630-2541  
:::tim_r1 at verifone.com