[volt-nuts] Poll

[Andreas Jahn]

Hello Frank,

I have made my first measurements with the LTZ1000 cirquit.
At the moment I have replaced the LTZ by a discrete "ref-amp"
consisting of a NPN and a zener to test the start-up behaviour
of the zener-current. (I do not want to kill my LTZ at the first startup).

I found out that the LT1013 is instable with capacitive loading
when using the cirquit from the datasheet without additional buffering.
In my configuration with the FET as buffer the output oscillates
with capacitive loading of greater than about 33nF.

So I will put a additionally resistor (10K) between the 120 Ohms resistor
and the negative input of the current regulator. And a capacitor (100nF)
between output and the negative input of the regulator.
With this configuration the cirquit is stable up to around 100uF
which should be sufficient.

Maybe the glitches that you recognized have a similar root cause.

With best regards

Andreas


----- Original Message ----- 
From: "Dr. Frank Stellmach" <drfrank.stellmach at freenet.de>
To: <volt-nuts at febo.com>
Sent: Tuesday, September 14, 2010 7:28 AM
Subject: [volt-nuts] Poll

Anyhow, after 3/4 year of permanent operation of both LTZs, if I run
them against the 5442 and the 3458A (pimped to 65°C operation), all 4
standards are within 1ppm or less. That gives me confidence that the
LTZs really have a drift of around 1ppm/year as stated in the data
sheet. So I ignore the glitches at the moment.

Frank