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lower ADXRS620 output impedance , higher ADC accuracy ?

Question asked by Guillaume on May 23, 2012
Latest reply on Jun 6, 2012 by Harvey


I use LTC1408 (ADC) to convert ADXL325 and ADXRS620 analog signals. LTC1408 ask to use a buffer amplifier before ADC to transform the analog signals, which have high source impedance.


ADXL325 has an output impedance of 32k for LP filter, so it is necessary to add a buffer to the signal.

For ADXRS620, the temperature output impedance is very high, so it is also needed to put a unit buffer to the signal before ADC.


My question is where to know the impedance of the gyro's rate signal. Is it high or low? Is it essential to use a unit buffer to the signal if a high ADC accuracy is required?


Thanks in advance