Tool/software:
I have used the LP2985 for about 20 years. My products require low noise voltage at 1, 10 , 100, Hz. I found that using Cnr = 1 uF improves the noise voltage considerably at at frequencies < 200 Hz.
Example LP2985 4V part with Cnr= 0.01 uF the noise voltage at 10 Hz is about 1.5 uV/sqrtHZ and with 1 uF is about 0.3 uV/sqrtHZ conditions: 5V input, load ~ 15 mA
Since measuring the noise our equipment was sold. Therefore we cannot perform this test on the New Chip.
1) How can I determine if I am getting the "New Chip" or the "Legacy Chip"the
2) Does anyone know the noise voltage with none higher cap value for Cnr?
3) What is the value of Rf shown in figure 7.2 of the R revision of the data sheet?
