What is the formula for ADC ENOB / SNR / Oversampling?

Core formula: SNR_ideal = 6.02·N + 1.76 dB ｜ ENOB = (SNR − 1.76)/6.02 ｜ 4× oversampling ≈ +1 bit. The tool returns results instantly using this formula and the selected parameters.

ADC ENOB / SNR / Oversampling

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Derive ENOB from measured SNR and see how many bits oversampling buys back — for when a "12-bit" ADC behaves like 10 bits.

Key points

ADC ENOB / SNR / Oversampling: Derive ENOB from measured SNR and see how many bits oversampling buys back — for when a "12-bit" ADC behaves like 10 bits. Formula: SNR_ideal = 6.02·N + 1.76 dB ｜ ENOB = (SNR − 1.76)/6.02 ｜ 4× oversampling ≈ +1 bit. Enter parameters on the DD-CAT IDE online tool page to get results instantly, with a calculation-model diagram that updates with the inputs. One bit of ENOB equals 6dB of SNR; typical culprits are reference noise, weak sample-and-hold drive and ground bounce from a broken return path. Oversampling with averaging only suppresses white noise — it does nothing for 50Hz mains pickup and its harmonics; filter or synchronise instead.

Inputs

SNR_ideal = 6.02·N + 1.76 dB ｜ ENOB = (SNR − 1.76)/6.02 ｜ 4× oversampling ≈ +1 bit

Calculation model (updates with parameters)

Ideal SNR	74.00 dB	6.02×12 + 1.76
Effective number of bits (ENOB)	11.34 bits
Gap from nominal	0.66 bits	room for improvement
1 LSB voltage	0.8057 mV	3.30V / 2^12
Equivalent noise (LSB)	1.58 LSB
Effective resolution voltage	1277.0 µV	Smallest change actually resolvable at this ENOB
ENOB after oversampling	11.34 bits	OSR=1 → +0.00 bits

Engineering notes

One bit of ENOB equals 6dB of SNR; typical culprits are reference noise, weak sample-and-hold drive and ground bounce from a broken return path.
Oversampling with averaging only suppresses white noise — it does nothing for 50Hz mains pickup and its harmonics; filter or synchronise instead.

FAQ

What is ADC ENOB / SNR / Oversampling for?: Derive ENOB from measured SNR and see how many bits oversampling buys back — for when a "12-bit" ADC behaves like 10 bits.
What is the formula for ADC ENOB / SNR / Oversampling?: Core formula: SNR_ideal = 6.02·N + 1.76 dB ｜ ENOB = (SNR − 1.76)/6.02 ｜ 4× oversampling ≈ +1 bit. The tool returns results instantly using this formula and the selected parameters.
What engineering notes should I keep in mind when using ADC ENOB / SNR / Oversampling?: One bit of ENOB equals 6dB of SNR; typical culprits are reference noise, weak sample-and-hold drive and ground bounce from a broken return path. Oversampling with averaging only suppresses white noise — it does nothing for 50Hz mains pickup and its harmonics; filter or synchronise instead.