Signal chain error budget
Combine explicit analogue front-end, ADC and reference error bounds referred to the ADC input.
Development preview. Check the assumptions below before relying on a result. Calculations run in your browser.
How it calculates
Model: Worst case = Σ|ei|; RSS = √Σei²; offset is amplified by noise gain; reference/gain errors act on the selected signal level.
Assumptions
- All terms are referred to the ADC input. Inverting/non-inverting bias-current bounds are summed independently, so cancellation is not presumed.
- RSS assumes independent error sources, including independence between an imported front end and ADC/reference errors. Shared reference or supply errors must not be counted twice.
- RSS of maximum bounds is a comparison metric, not a confidence interval. Statistical use requires independently characterised distributions. Quantisation and random noise are not added to these static error bounds.
Worked example
These are the calculator's default inputs. Change any input above to recalculate.
Inputs
- Front-end error source
- manual
- Imported front-end worst-case error
- 0 V
- Imported front-end RSS error
- 0 V
- ADC bits
- 16
- ADC full-scale span
- 5 V
- Nominal ADC input magnitude
- 2.5 V
- Front-end noise gain
- 1
- Amplifier input offset bound
- 0.00005 V
- Amplifier offset drift
- 5e-7 V/°C
- Inverting input bias-current bound
- 1e-9 A
- Non-inverting bias-current bound
- 1e-9 A
- Feedback resistance
- 10000 Ω
- Non-inverting source resistance
- 1000 Ω
- Common-mode change
- 1 V
- CMRR
- 100 dB
- Supply change
- 0.1 V
- PSRR
- 100 dB
- Front-end gain error bound
- 0.01 %
- ADC offset bound
- 1 LSB
- ADC INL bound
- 1 LSB
- ADC gain error bound
- 0.01 %
- Reference initial tolerance
- 0.02 %
- Reference temperature drift
- 5 ppm/°C
- Temperature excursion magnitude
- 30 °C
Results
- Worst-case sum
- 0.00161459 V
- RSS of entered error bounds
- 0.000729173 V
- Worst-case error
- 21.1627 LSB
- RSS error
- 9.55742 LSB
- Worst-case full-scale error
- 0.0322918 %
- Worst-case full-scale error
- 322.918 ppm