AD9226 Analog Devices, AD9226 Datasheet - Page 7

• Manufacturer Part Number: AD9226
• Description: 12-Bit, 65 MSPS Analog-to-Digital Converter
• Manufacturer: Analog Devices

Specifications of AD9226

• Resolution (bits): 12bit
• # Chan: 1
• Sample Rate: 65MSPS
• Interface: Par
• Analog Input Type: Diff-Uni,SE-Uni
• Ain Range: (Vref) p-p,1 V p-p,2 V p-p,Uni (Vref),Uni 1.0V,Uni 2.0V
• Adc Architecture: Pipelined
• Pkg Type: QFP,SOP

DEFINITIONS OF SPECIFICATIONS
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 12-bit resolution indicates that all 4096
codes, respectively, must be present over all operating ranges.
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 positive full scale.
Gain error is the deviation of the actual difference between first
and last code transitions 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.
APERTURE JITTER
Aperture jitter is the variation in aperture delay for successive
samples and can be manifested as noise on the input to the ADC.
APERTURE DELAY
Aperture delay is a measure of the sample-and-hold amplifier
(SHA) performance and is measured from the rising edge of the
clock input to when the input signal is held for conversion.
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.
MIN
or T
MAX
.
EFFECTIVE NUMBER OF BITS (ENOB)
For a sine wave, SINAD can be expressed in terms of the num-
ber of bits. Using the following formula,
it is possible to obtain 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 com-
ponents 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.
ENCODE PULSEWIDTH DUTY CYCLE
Pulsewidth high is the minimum amount of time that the clock
pulse should be left in the logic “1” state to achieve rated per-
formance; pulsewidth low is the minimum time the clock pulse
should be left in the low state. At a given clock rate, these specs
define an acceptable clock duty cycle.
MINIMUM CONVERSION RATE
The clock rate at which the SNR of the lowest analog signal
frequency drops by no more than 3 dB below the guaranteed limit.
MAXIMUM CONVERSION RATE
The encode rate at which parametric testing is performed.
OUTPUT PROPAGATION DELAY
The delay between the clock logic threshold and the time when
all bits are within valid logic levels.
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 levels are lowered) or in dBFS (always
related back to converter full scale).
N = (SINAD – 1.76)/6.02
AD9226