Rainbow Electronics ADC10321 - Manual (Page 10)

Specification Definitions
APERTURE JITTER is the variation in aperture delay from
sample to sample. Aperture jitter shows up as input noise.
APERTURE DELAY See Sampling Delay.
DIFFERENTIAL GAIN ERROR is the percentage difference
between the output amplitudes of a given amplitude small
signal, high frequency sine wave input at two different dc
input levels.
DIFFERENTIAL PHASE ERROR is the difference in the
output phase of a small signal sine wave input at two differ-
ent dc input levels.
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of
the maximum deviation from the ideal step size of 1 LSB.
EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE
BITS) is another method of specifying Signal-to-Noise and
Distortion Ratio (S/N+D or SINAD). ENOB is defined as
(SINAD −1.76) / 6.02.
FULL POWER BANDWIDTH is a measure of the frequency
at which the reconstructed output fundamental drops 3 dB
below its 1MHz value for a full scale input. The test is
performed with f
IN
equal to 100 kHz plus integral multiples of
f
CLK
. The input frequency at which the output is −3 dB
relative to the1MHz input signal is the full power bandwidth.
FULL SCALE (FS) INPUT RANGE of the ADC is the input
range of voltages over which the ADC will digitize that input.
For V
REF
+ = 3.50V and V
REF
− = 1.50V, FS = (V
REF
+) −
(V
REF
−) = 2.00V.
FULL SCALE OFFSET ERROR is a measure of how far the
last code transition is from the ideal 1
1 ⁄
2
LSB below V
REF
+
and is defined as V
1023
−1.5 LSB − V
REF
+ , where V
1023
is
the voltage at which the transitions from code 1022 to 1023
occurs.
FULL SCALE STEP RESPONSE is defined as the time
required after V
IN
goes from V
REF
− to V
REF
+, or V
REF
+ to
V
REF
−, and settles sufficiently for the converter to recover
and make a conversion with its rated accuracy.
INTEGRAL NON-LINEARITY (INL) is a measure of the
deviation of each individual code from a line drawn from
negative full scale (
1 ⁄ 2 LSB below the first code transition)
through positive full scale (1 1 ⁄
2
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.
OUTPUT DELAY is the time delay after the fall of the input
clock before the data update is present at the output pins.
OUTPUT HOLD TIME is the length of time that the output
data is valid after the fall of the input clock.
OVER RANGE RECOVERY TIME is the time required after
V
IN
goes from AGND to V
REF
+ or V
IN
goes from V
A
to V
REF
−
for the converter to recover and make a conversion with its
rated accuracy.
PIPELINE DELAY (LATENCY) is the number of clock cycles
between initiation of conversion and when that data is pre-
sented to the output driver stage. Data for any given sample
is available by the Pipeline Delay plus the Output Delay after
that sample is taken. New data is available at every clock
cycle, but the data lags the conversion by the pipeline delay.
PSRR (POWER SUPPLY REJECTION RATIO) is the ratio
of the change in dc power supply voltage to the resulting
change in Full Scale Error, expressed in dB.
SAMPLING (APERTURE) DELAY or APERTURE TIME is
that time required after the fall of the clock input for the
sampling switch to open. The sample is effectively taken this
amount of time after the fall of the clock input.
SIGNAL TO NOISE RATIO (SNR) 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.
SIGNAL TO NOISE PLUS DISTORTION (S/(N+D) or SI-
NAD) 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 har-
monics but excluding dc.
SPURIOUS FREE DYNAMIC RANGE (SFDR) is the differ-
ence, expressed in dB or dBc, 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.
TOTAL HARMONIC DISTORTION (THD) is the ratio, ex-
pressed in dB, of the rms total of the first six harmonic
components, to the rms value of the input signal.
ZERO SCALE OFFSET ERROR is the difference between
the ideal input voltage (
1 ⁄
2
LSB) and the actual input voltage
that just causes a transition from an output code of zero to
an output code of one.
ADC10321
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