Summary

Rick Lyons presents a concise, practical rule-of-thumb for specifying the maximum noise an amplifier can contribute when driving an ADC. The paper shows how to relate amplifier noise spectral density, system bandwidth and ADC characteristics to SNR/ENOB so engineers can perform quick noise-budget calculations and pick or specify input drivers.

Key Takeaways

• Calculate the maximum allowable input-referred amplifier noise from desired ADC SNR and full-scale input.
• Integrate amplifier noise spectral density over system bandwidth to obtain RMS noise for comparison with ADC noise sources.
• Compare amplifier noise to ADC quantization noise and ENOB to determine whether the amplifier or ADC dominates system noise.
• Apply the rule-of-thumb to choose amplifier gain, bandwidth and anti-aliasing filter parameters to meet dynamic-range targets.

Who Should Read This

Analog/mixed-signal and DSP engineers (practicing, with some ADC experience) who need to select or specify amplifier drivers to meet ADC SNR and dynamic-range requirements.

TimelessIntermediate

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