775nV Low Noise Voltage Reference Measurement Techniques - LTC6655

Frequently, voltage reference stability and noise define measurement limits in instrumentation systems. In particular, reference noise often sets stable resolution limits. Reference voltages have decreased with the continuing drop in system power supply voltages, making reference noise increasingly important. The compressed signal processing range mandates a commensurate reduction in reference noise to maintain resolution. Noise ultimately translates into quantization uncertainty in A-to-D converters, introducing jitter in applications such as scales, inertial navigation systems, infrared thermography, DVMs and medical imaging apparatus.

A new low voltage reference, the LTC6655, has only 0.3ppm (775nV) noise at 2.5VOUT. Verifying this extremely low noise level constitutes a high order difficulty measurement, requiring a 1Hz to 10Hz noise floor below 160 nanovolts. This video summarizes the measurement technique and presents results.