chopper stabilized bandgap

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Hi
I have designed a BG reference with 1.28 output voltage and 2v supply, the flicker noise is high since I used only 1uA in the branches (the power consumption is very critical in my design), now I heard about what is called chopper stabilization but I couldn't find any resource explaining exactly what it is, so can some one please provide me with anything useful regarding that ? and perhaps explain it
thx guys
 

We've done this and it pays off for noise & stability. You have to
post-filter it. You may also chop the error amp (if any). The
scheme I know, just uses CMOS switches to ping-pong the
diff pair inputs and outputs.

There is some residual noise as the offset becomes periodically
reversing, averaged to zero. In a switching regulator this is fine,
in a low noise linear it would not be because you put a baseband
clock note and harmonics onto the output.
 

Chopper circuit switchs input stage periodically. So flick noise and offset can be cancelled by averaging. Increase switching frequency will helps for post-filter.
 


have you checked the dominant source of your flicker noise is actually the diff pair and not other devices (e.g. current sources)?
 

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