Well Capacity & Dynamic Range

DR = 20·log₁₀(Nwell/σread). C = Nwell·q/Vswing. Larger wells → more DR at a fixed read noise.

Model: Textbook approximation

Dynamic range = 80.00 dB

Usable bits = 13.3 bits

Pixel capacitance = 5.341 fF

Conversion gain = 30.00 µV/e⁻

Read noise at the sense node σ_r·q/C = 150.0 µV

Full well density = 2000 e⁻/μm²

Min detectable (SNR = 3, read + shot noise) = 20.2 e⁻

DR = 20·log₁₀(N_well/σ_read), C = N_well·q/V_swing, S_min = (9 + √(81 + 36σ²))/2

Model and references

Textbook approximation. A standard approximation from the literature (for example paraxial, plane-wave or Gaussian-beam), valid within the range the page states. About the tiers

Definitions: DR = 20·log₁₀(N_well/σ_read), usable bits log₂(N_well/σ_read), and a linear sense node C = N_well·q/V_swing with conversion gain q/C. Real sense-node capacitance grows with charge, so the conversion gain falls near full well. σ_r is held fixed as N varies; at a fixed swing and fixed sense-node voltage noise, σ_r grows ∝ N and DR = 20·log(V_swing/v_n) does not depend on well depth. The minimum detectable signal solves S/√(S + σ²) = 3, with the signal's own shot noise.

  1. Janesick J. R. (2007). Photon Transfer: DN → λ. SPIE Press. Full well, sense-node conversion gain and dynamic range. doi:10.1117/3.725073
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