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Bandgap Buffer Amp in LL08

Question asked by John Musselman on May 15, 2012
Latest reply on May 31, 2012 by John Musselman

I'm using the LL08 and have some questions about the bandgap buffer amp.  The datasheet seems to hint that the buffer draws a bit of current, but does not specify how much.  My application runs at an average draw in the 10 uA range and I do see a lot more draw if I leave the buffer on all the time.

 

So I turn the buffer on before making an ADC measurement (once a second) and then turn it off afterwards.  But doing this,  the reading is extremely sensitive to temperature.  I added a small delay after turning on the buffer and before starting the ADC conversion and the problem seems to have gone away, but I'm still testing it.  I assume the buffer needs time to settle.

 

Any help on this?  What is the bandgap buffer current draw and settling time? I believe the datasheet is mute on this.

 

John

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