AD9260 Analog Devices, AD9260 Datasheet - Page 12

• Manufacturer Part Number: AD9260
• Description: 16-Bit High Speed Oversampled A/D Converter
• Manufacturer: Analog Devices

Specifications of AD9260

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: 2.5MSPS
• Interface: Par
• Analog Input Type: Diff-Uni
• Ain Range: 4 V p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: QFP

AD9260
TERMINOLOGY
Integral Nonlinearity (INL)
INL refers to the deviation of each individual code from a line
drawn from “negative full scale” through “positive full scale. ”
The point used as “negative full scale” occurs 1/2 LSB before the
first code transition. “Positive full scale” is defined as a level 1
1/2 LSB beyond the last code transition. The deviation is
measured from the middle of each particular code to the true
straight line.
Differential Nonlinearity (DNL, No Missing Codes)
An ideal ADC exhibits code transitions that are exactly 1 LSB
apart. DNL is the deviation from this ideal value. Guaranteed
no missing codes to 14-bit resolution indicates that all 16384
codes, respectively, must be present over all operating ranges.
NOTE: Conventional INL and DNL measurements don’t really
apply to ∑∆ converters: the DNL looks continually better if
longer data records are taken. For the AD9260, INL and DNL
numbers are given as representative.
Zero Error
The major carry transition should occur for an analog value 1/2
LSB below VINA = VINB. Zero error is defined as the deviation
of the actual transition from that point.
Gain Error
The first code transition should occur at an analog value 1/2
LSB above negative full scale. The last transition should occur at
an analog value 1 1/2 LSB below the nominal full scale. Gain
error is the deviation of the actual difference and the ideal
difference between first and last code transitions.
Temperature Drift
The temperature drift for zero error and gain error specifies the
maximum change from the initial (+25°C) value to the value at
T
Power Supply Rejection
The specification shows the maximum change in full scale from
the value with the supply at the minimum limit to the value
with the supply at its maximum limit.
MIN
or T
MAX
.
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Aperture Jitter
Aperture jitter is the variation in aperture delay for successive
samples and is manifested as noise on the input to the A/D.
Signal-to-Noise and Distortion (S/N+D, SINAD) Ratio
S/N+D is the ratio of the rms value of the measured input signal
to the rms sum of all other spectral components below the
Nyquist frequency, including harmonics but excluding dc. The
value for S/N+D is expressed in decibels.
Effective Number of Bits (ENOB)
For a sine wave, SINAD can be expressed in terms of the
number of bits. Using the following formula, it is possible to get
a measure of performance expressed as N, the effective number
of bits:
Thus, effective number of bits for a device for sine wave inputs
at a given input frequency can be calculated directly from its
measured SINAD.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of the first six harmonic
components to the rms value of the measured input signal and
is expressed as a percentage or in decibels.
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the measured input signal to
the rms sum of all other spectral components below the Nyquist
frequency, excluding the first six harmonics and dc. The value
for SNR is expressed in decibels.
Spurious-Free Dynamic Range (SFDR)
SFDR is the difference in dB between the rms amplitude of the
input signal and the peak spurious signal.
Two-Tone SFDR
The ratio of the rms value of either input tone to the rms value
of the peak spurious component. The peak spurious component
may or may not be an IMD product. May be reported in dBc
(i.e., degrades as signal level is lowered), or in dBFS (always
related back to converter full scale).
N = (SINAD − 1.76)/6.02