Turning a Noise Density Figure into Your Own Averaging Window
Square the quotient of specified noise density over target resolution to establish the equivalent noise bandwidth required for averaging filter design.
Reference Voltage Stability
Output Consistency
Precision electronic systems require a steady potential to maintain the accuracy of their internal conversions. Reference voltage stability measures the ability of a regulator to hold its output value despite changes in external conditions. It is the primary indicator of the long term reliability of a measurement system.
Load Regulation
Variations in the current drawn by the system can cause the output to sag or spike. A high degree of reference voltage stability ensures that the digital to analog converter produces a consistent output regardless of the processor activity. This regulation is maintained by an internal feedback loop.
Thermal Hysteresis
Temperature cycles can lead to permanent shifts in the output if the internal stresses on the silicon die are not managed. Reference voltage stability is tested by heating and cooling the part and measuring the return to the initial value. Buried Zener diodes often provide better stability than bandgap references in harsh environments.
Aging Effect
Chemical changes in the semiconductor material cause a slow drift over thousands of hours of operation. High quality parts are burned in at the factory to move the device past its initial high drift phase. Reference voltage stability determines the frequency of recalibration for the entire instrument.