ADC101S021EVAL National Semiconductor, ADC101S021EVAL Datasheet - Page 7

• Manufacturer Part Number: ADC101S021EVAL
• Manufacturer: National Semiconductor

Specifications of ADC101S021EVAL

• Lead Free Status / Rohs Status: Not Compliant

Specification Definitions
ACQUISITION TIME is the time required to acquire the input
voltage. That is, it is time required for the hold capacitor to
charge up to the input voltage.
APERTURE DELAY is the time between the fourth falling
SCLK edge of a conversion and the time when the input signal
is acquired or held for conversion.
APERTURE JITTER (APERTURE UNCERTAINTY) is the
variation in aperture delay from sample to sample. Aperture
jitter manifests itself as noise in the output.
CONVERSION TIME is the time required, after the input volt-
age is acquired, for the ADC to convert the input voltage to a
digital word.
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of
the maximum deviation from the ideal step size of 1 LSB.
DUTY CYCLE is the ratio of the time that a repetitive digital
waveform is high to the total time of one period. The specifi-
cation here refers to the SCLK.
EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE
BITS) is another method of specifying Signal-to-Noise and
Distortion
(SINAD − 1.76) / 6.02 and says that the converter is equiva-
lent to a perfect ADC of this (ENOB) number of bits.
FULL POWER BANDWIDTH 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.
GAIN ERROR is the deviation of the last code transition
(111...110) to (111...111) from the ideal (V
ter adjusting for offset error.
INTEGRAL NON-LINEARITY (INL) is a measure of the de-
viation of each individual code from a line drawn from negative
full scale (½ LSB below the first code transition) through pos-
itive 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.
INTERMODULATION DISTORTION (IMD) is the creation of
additional spectral components as a result of two sinusoidal
frequencies being applied to the ADC input at the same time.
or
SINAD.
ENOB
is
REF
− 1.5 LSB), af-
defined
as
7
It is defined as the ratio of the power in the second and third
order intermodulation products to the sum of the power in both
of the original frequencies. IMD is usually expressed in dB.
MISSING CODES are those output codes that will never ap-
pear at the ADC outputs. The ADC101S021 is guaranteed not
to have any missing codes.
OFFSET ERROR is the deviation of the first code transition
(000...000) to (000...001) from the ideal (i.e. GND + 0.5 LSB).
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 sam-
pling frequency, not including harmonics or d.c.
SIGNAL TO NOISE PLUS DISTORTION (S/N+D or
SINAD) Is the ratio, expressed in dB, of the rms value of the
input signal to the rms value of all of the other spectral com-
ponents below half the clock frequency, including harmonics
but excluding d.c.
SPURIOUS FREE DYNAMIC RANGE (SFDR) is the differ-
ence, expressed in dB, between the desired signal amplitude
to the amplitude of the peak spurious spectral component,
where a spurious spectral component is any signal present in
the output spectrum that is not present at the input and may
or may not be a harmonic.
TOTAL HARMONIC DISTORTION (THD) is the ratio, ex-
pressed in dB or dBc, of the rms total of the first five harmonic
components at the output to the rms level of the input signal
frequency as seen at the output. THD is calculated as
where A
put and A
harmonic frequencies.
THROUGHPUT TIME is the minimum time required between
the start of two successive conversion. It is the acquisition
time plus the conversion time.
f1
is the RMS power of the input frequency at the out-
f2
through A
f6
are the RMS power in the first 5
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