ADC08D1020DEV/NOPB National Semiconductor, ADC08D1020DEV/NOPB Datasheet - Page 15

• Manufacturer Part Number: ADC08D1020DEV/NOPB
• Description: BOARD DEV FOR ADC08D1020
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of ADC08D1020DEV/NOPB

• Number Of Adc's: 2
• Number Of Bits: 8
• Sampling Rate (per Second): 1G
• Data Interface: Serial
• Inputs Per Adc: 1 Differential
• Input Range: 870 mVpp
• Power (typ) @ Conditions: 1.6W @ 1GSPS
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: ADC08D1020
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ADC08D1020DEV

Specification Definitions
APERTURE (SAMPLING) DELAY is the amount of delay,
measured from the sampling edge of the Clock input, after
which the signal present at the input pin is sampled inside the
device.
APERTURE JITTER (t
from sample to sample. Aperture jitter shows up as input
noise.
CODE ERROR RATE (C.E.R.) is the probability of error and
is defined as the probable number of word errors on the ADC
output per unit of time divided by the number of words seen
in that amount of time. A C.E.R. of 10
statistical error in one word about every four (4) years.
CLOCK DUTY CYCLE is the ratio of the time that the clock
waveform is at a logic high to the total time of one clock period.
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of
the maximum deviation from the ideal step size of 1 LSB.
Measured at sample rate = 500 MSPS with a 1MHz input
sinewave.
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 (FPBW) 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 from the ideal slope of the
transfer function. It can be calculated from Offset and Full-
Scale Errors:
Error
Scale Error)
Scale Error = Positive Gain Error + Negative Gain Error
INTEGRAL NON-LINEARITY (INL) is a measure of worst
case deviation of the ADC transfer function from an ideal
straight line drawn through the ADC transfer function. The
deviation of any given code from this straight line is measured
from the center of that code value step. The best fit method
is used
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.
It is defined as the ratio of the power in the second and third
order intermodulation products to the power in one of the
original frequencies. IMD is usually expressed in dBFS.
LSB (LEAST SIGNIFICANT BIT) is the bit that has the small-
est value or weight of all bits. This value is
where V
the FSR input and "n" is the ADC resolution in bits, and which
is 8 for the ADC08D1020.
LOW VOLTAGE DIFFERENTIAL SIGNALING (LVDS)
DIFFERENTIAL VOLTAGE (V
absolute value of the difference between the V
signals; each measured with respect to Ground.
Positive Gain Error = Offset Error − Positive Full-Scale
Negative Gain Error = −(Offset Error − Negative Full-
Gain Error = Negative Full-Scale Error − Positive Full-
FS
is the differential full-scale amplitude V
Ratio,
or
AJ
SINAD.
) is the variation in aperture delay
V
FS
/ 2
ID
N
and V
ENOB
-18
OD
) is two times the
corresponds to a
is
D
defined
+ and V
IN
as set by
D
as
−
15
LVDS OUTPUT OFFSET VOLTAGE (V
between the D+ and D− pins output voltage with respect to
ground, i.e., [(V
MISSING CODES are those output codes that are skipped
and will never appear at the ADC outputs. These codes can-
not be reached with any input value.
MSB (MOST SIGNIFICANT BIT) is the bit that has the largest
value or weight. Its value is one half of full scale.
NEGATIVE FULL-SCALE ERROR (NFSE) is a measure of
how far the first code transition is from the ideal 1/2 LSB above
a differential −V
age is assumed to be ideal, so this error is a combination of
full-scale error and reference voltage error.
OFFSET ERROR (V
scale point is from the ideal zero voltage differential input.
Offset Error = Actual Input causing average of 8k samples to
result in an average code of 127.5.
OUTPUT DELAY (t
Pipeline Delay) after the falling edge of CLK+ before the data
update is present at the output pins.
OVER-RANGE RECOVERY TIME is the time required after
the differential input voltages goes from ±1.2V to 0V for the
converter to recover and make a conversion with its rated ac-
curacy.
PIPELINE DELAY (LATENCY) is the number of input clock
cycles between initiation of conversion and when that data is
presented to the output driver stage. New data is available at
every clock cycle, but the data lags the conversion by the
Pipeline Delay plus the t
POSITIVE FULL-SCALE ERROR (PFSE) is a measure of
how far the last code transition is from the ideal 1-1/2 LSB
below a differential +V
ence voltage is assumed to be ideal, so this error is a combi-
nation of full-scale error and reference voltage error.
POWER SUPPLY REJECTION RATIO (PSRR) can be one
of two specifications. PSRR1 (DC PSRR) is the ratio of the
change in full-scale error that results from a power supply
voltage change from 1.8V to 2.0V. PSRR2 (AC PSRR) is a
measure of how well an a.c. signal injected on the power sup-
ply is rejected from the output and is measured with a 248
MHz, 50 mV
ratio of the output amplitude of that signal at the output to its
amplitude on the power supply pin. PSRR is expressed in dB.
SIGNAL TO NOISE RATIO (SNR) is the ratio, expressed in
dB, of the rms value of the input signal at the output to the rms
value of the sum of all other spectral components below one-
half the sampling 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 at the output to the rms value of all of the other
P-P
D
IN
signal riding upon the power supply. It is the
+) + ( V
/2. For the ADC08D1020 the reference volt-
OFF
OD
IN
) is the time delay (in addition to
D
OD
) is a measure of how far the mid-
FIGURE 1.
/2. For the ADC08D1020 the refer-
−)] / 2.
.
OS
) is the midpoint
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