is the variation in aperture delay from sample to sample. Aperture jitter manifests itself as noise in the output.

is the variation in aperture delay from sample to sample. Aperture jitter manifests itself as noise in the output.

is the measure of the maximum deviation from the ideal step size of 1 LSB.

is the ratio of the time that a repetitive digital waveform is high to the total time of one period. The specification here refers to the SCLK.

is another method of specifying Signal-to-Noise and Distortion or SINAD. ENOB is defined as (SINAD - 1.76) / 6.02 and says that the converter is equivalent to a perfect ADC of this (ENOB) number of bits.

is a measure of the frequency at which the reconstructed output fundamental drops 3 dB below its low frequency value for a full scale input.

is the deviation of the last code transition (111...110) to (111...111) from the ideal (V_REF – 1.5 LSB for ADCS7476 and ADCS7477, V_REF – 1 LSB for ADCS7478), after adjusting for offset error.

is a measure of the deviation of each individual code from a line drawn from negative full scale (½ LSB below the first code transition) through positive full scale (½ LSB above the last code transition). The deviation of any given code from this straight line is measured from the center of that code value.

is the creation of additional spectral components as a result of two sinusoidal frequencies being applied to the ADC input at the same time. It is defined as the ratio of the power in the either the two second order or all four third order intermodulation products to the sum of the power in both of the original frequencies. IMD is usually expressed in dBFS.

are those output codes that never appear at the ADC outputs. ADCS747x is ensured not to have any missing codes.

is the deviation of the first code transition (000...000) to (000...001) from the ideal (that is, GND + 0.5 LSB for the ADCS7476 and ADCS7477, and GND + 1 LSB for the ADCS7478).

is the ratio, expressed in dB, of the rms value of the input signal to the rms value of the sum of all other spectral components below one-half the sampling frequency, not including harmonics or DC.

Is the ratio, expressed in dB, of the rms value of the input signal to the rms value of all of the other spectral components below half the clock frequency, including harmonics but excluding DC.

is the difference, expressed in dB, between the rms values of the input signal and the peak spurious signal, where a spurious signal is any signal present in the output spectrum that is not present at the input.

is the ratio, expressed in dBc, of the rms total of the first five harmonic levels at the output to the level of the fundamental at the output. THD is calculated as:

Equation 1.

where

• f₁ is the RMS power of the fundamental (output) frequency
• f₂ through f₆ are the RMS power in the first 5 harmonic frequencies

is the worst deviation found from the ideal transfer function. As such, it is a comprehensive specification which includes full scale error, linearity error, and offset error.