LT1027 based Reference Voltage

[iTist]

Hi,

beside the two killer Reference Voltage threads, i would like to present my little voltage reference for beginners.

It is an unbufferd 5V reference based on the LT1027. I use a LT1763 as low noise regulator which is fed by a linear 15V power supply.
I put it all in a metal case and thermal Chamber made of styrofoam with an build in heater.

More details and some measurements at:
http://itist.de/2013/09/lt-1027-basierte-5-v-referenzspannungsquelle/


Greetz

Oliver



The LM399s were waiting......

[cellularmitosis]

neat!  what are you using as a heater circuit?

edit: ah, I see the PTC heater foil used as the heating element in your blog post.  But how are you measuring / regulating the temperature?

[iTist]

Hi,
I am using a Thermocouple Type K for the temperature measurement.
The Foil is "self regulating" via its PTC characteristic.

I plan to build a temperature control with an KTYxx and an OpAmp but first  I have to measure the real temperature of the case.
My target is around 32° C because the maximum ambient Temperature is 26°C. Maybe i need another heater (Ceramic Resistors).
Greetz

Oliver

[Nuno_pt]

Try this as a heater, it's at 40° C but very stable.

http://www.kuhne-electronic.de/en/products/crystal-heater/qh-40-a.html

[branadic]

Try this as a heater, it's at 40° C but very stable.

My guess is, that this heater (QH40A) is a bit to small for this application. But I can confirm that it is a neat little beast.
I have it assembled on my chip resistors (only 5ppm/K) of my LM399 reference and on a MAX6325 in plastic package. The heater is only somewhat bigger compared to a SO8 adapter board.

[iTist]

My guess is, that this heater is a bit to small for this application. But I can confirm that the QH 40 A is a neat little beast.
I have it assembled on my chip resistors (only 5ppm/K) of my LM399 and on a MAX6325 in plastic package. The heater is only somewhat bigger compared to a SO8 adapter board.

Hi,

I think that's true but this was for a first cheap test. Is the QH 40 suitable for the whole metal case ore only for the reference IC? Could i order it at Kuehne electronic or is there a distributor?

Thanks.

Greetz

Oliver

[branadic]

Is the QH 40 suitable for the whole metal case ore only for the reference IC?

Only for the reference. The heater is only 10,5mm x 14,0 mm in size, operating voltage 8 ... 12V and about 80mA inrush current.

[iTist]

Okay,

i used the foil for the whole case it draws 180mA at 12V and i got a temperature difference of approx. 18°. I haven't done the math.
Need a more precise thermometer. Maybe a sensor with I2C bus?

Greetz

Oliver