ADC1175-50CIMT National Semiconductor, ADC1175-50CIMT Datasheet - Page 9

• Manufacturer Part Number: ADC1175-50CIMT
• Description: 8-Bit/ 50 MSPS/ 125 mW A/D Converter
• Manufacturer: National Semiconductor

Specification Definitions
ANALOG INPUT BANDWIDTH is a measure of the fre-
quency at which the reconstructed output fundamental drops
3 dB below its low frequency value for a full scale input. The
test is performed with f
tiples of f
−3 dB relative to the low frequency input signal is the full
power bandwidth.
APERTURE JITTER is the time uncertainty of the sampling
point (t
BOTTOM OFFSET is the difference between the input volt-
age that just causes the output code to transition to the first
code and the negative reference voltage. Bottom Offset is
defined as E
sition input voltage. Note that this is different from the normal
Zero Scale Error.
DIFFERENTIAL GAIN ERROR is the percentage difference
between the output amplitudes of a high frequency recon-
structed sine wave at two different dc levels.
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of
the maximum deviation from the ideal step size of 1 LSB.
DNL is measured at the rated clock frequency with a ramp
input.
DIFFERENTIAL PHASE ERROR is the difference in the out-
put phase of a reconstructed small signal sine wave at two
different dc levels.
EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE
BITS) is another method of specifying Signal-to-Noise and
Distortion Ratio, or SINAD. ENOB is defined as (SINAD −
1.76)/6.02 and says that the converter is equivalent to a per-
fect ADC of this (ENOB) number of bits.
INTEGRAL NON-LINEARITY (INL) is a measure of the de-
viation of each individual codes from a line drawn from zero
scale (1/2 LSB below the first code transition) through posi-
tive full scale (1/2 LSB above the last code transition). The
deviation of any given code from this straight line is mea-
sured from the center of that code value. The end point test
method is used. INL is measured at rated clock frequency
with a ramp input.
OUTPUT DELAY is the time delay after the rising edge of
the input clock before the data update is present at the out-
put pins.
DS
), or the range of variation in the sampling delay.
CLK
OB
. The input frequency at which the output is
= V
ZT
− V
IN
RB
equal to 100 kHz plus integer mul-
, where V
ZT
is the first code tran-
9
OUTPUT HOLD TIME is the length of time that the output
data is valid after the rise of the input clock.
PIPELINE DELAY (LATENCY) is the number of clock cycles
between initiation of conversion and when that data is pre-
sented to the output stage. Data for any given sample is
available 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.
SAMPLING (APERTURE) DELAY, or t
quired after the falling edge of the clock for the sampling
switch to open (in other words, for the Sample/Hold circuit to
go from the “sample” mode into the “hold” mode). The
Sample/Hold circuit effectively stops capturing the input sig-
nal and goes into the “hold” mode t
low.
SIGNAL TO NOISE RATIO (SNR) is the ratio of the rms
value of the input signal to the rms value of the other spectral
components below one-half the sampling frequency, not in-
cluding harmonics or dc.
SIGNAL TO NOISE PLUS DISTORTION (S/(N+D) or
SINAD) is the ratio 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.
SPURIOUS FREE DYNAMIC RANGE (SFDR) is the differ-
ence, 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.
TOP OFFSET is the difference between the positive refer-
ence voltage and the input voltage that just causes the out-
put code to transition to full scale and is defined as E
V
age. Note that this is different from the normal Full Scale Er-
ror.
TOTAL HARMONIC DISTORTION (THD) is the ratio of the
rms total of the first six harmonic components to the rms
value of the input signal.
FT
− V
RT
. Where V
FT
is the full scale transition input volt-
DS
after the clock goes
DS
, is the time re-
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OT
=