SPECIFICATION DEFINITIONS
APERTURE DELAY
Aperture delay represents the point in time, relative to the
rising edge of the CLOCK input, that the analog input is
sampled.
APERTURE JITTER
The variations in aperture delay for successive samples.
DIFFERENTIAL GAIN (DG)
A signal consisting of a sine wave superimposed on various
DC levels is applied to the input. Differential gain is the
maximum variation in the sampled sine wave amplitudes at
these DC levels.
DIFFERENTIAL PHASE (DP)
A signal consisting of a sine wave superimposed on various
DC levels that is applied to the input. Differential phase is the
maximum variation in the sampled sine wave phases at these
DC levels.
EFFECTIVE NUMBER OF BITS (ENOB)
SINAD = 6.02N + 1.76, where N is equal to the effective
number of bits.
DIFFERENTIAL NONLINEARITY (DNL)
Error in the width of each code from its theoretical value.
(Theoretical = V
FS
/2
N
)
INTEGRAL NONLINEARITY (INL)
Linearity error refers to the deviation of each individual code
(normalized) from a straight line drawn from -Fs through +Fs.
The deviation is measured from the edge of each particular
code to the true straight line.
OUTPUT DELAY
Time between the clock's triggering edge and output data
valid.
OVERVOLTAGE RECOVERY TIME
The time required for the ADC to recover to full accuracy after
an analog input signal 125% of full scale is reduced to 50%
of the full-scale value.
SIGNAL-TO-NOISE RATIO (SNR)
The ratio of the fundamental sinusoid power to the total noise
power. Harmonics are excluded.
SIGNAL-TO-NOISE AND DISTORTION (SINAD)
The ratio of the fundamental sinusoid power to the total noise
and distortion power.
TOTAL HARMONIC DISTORTION (THD)
The ratio of the total power of the first 64 harmonics to the
power of the measured sinusoidal signal.
SPURIOUS FREE DYNAMIC RANGE (SFDR)
The ratio of the fundamental sinusoidal amplitude to the
single largest harmonic or spurious signal.
N=
SINAD - 1.76
6.02
+/- FULL-SCALE ERROR (GAIN ERROR)
Difference between measured full scale response
[(+Fs) - (-Fs)] and the theoretical response (+4 V -2 LSBs)
where the +FS (full scale) input voltage is defined as the
output transition between 1-10 and 1-11 and the -FS input
voltage is defined as the output transition between 0-00 and
0-01.
INPUT BANDWIDTH
Small signal (50 mV) bandwidth (3 dB) of analog input stage.
SPT7920
5
3/10/97
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
