AD9772A
DEFINITIONS OF SPECIFICATIONS
Linearity Error (Also Called Integral Nonlinearity or INL)
Settling Time
Linearity error is defined as the maximum deviation of the actual
analog output from the ideal output, determined by a straight
line drawn from zero to full scale.
Differential Nonlinearity (or DNL)
The time required for the output to reach and remain within a
specified error band about its final value, measured from the
start of the output transition.
Glitch Impulse
DNL is the measure of the variation in analog value, normalized
to full scale, associated with a 1 LSB change in digital input code.
Monotonicity
Asymmetrical switching times in a DAC give rise to undesired
output transients that are quantified by a glitch impulse. It is
specified as the net area of the glitch in pV-s.
Spurious-Free Dynamic Range
A D/A converter is monotonic if the output either increases or
remains constant as the digital input increases.
Offset Error
The difference, in dB, between the rms amplitude of the output
signal and the peak spurious signal over the specified bandwidth.
Total Harmonic Distortion
The deviation of the output current from the ideal of zero is
called offset error. For I
OUTA
, 0 mA output is expected when the
inputs are all 0s. For I
OUTB
, 0 mA output is expected when all
inputs are set to 1s.
Gain Error
THD is the ratio of the rms sum of the first six harmonic com-
ponents to the rms value of the measured fundamental. It is
expressed as a percentage or in decibels (dB).
Signal-to-Noise Ratio (SNR)
The difference between the actual and ideal output span. The
actual span is determined by the output when all inputs are set
to 1s, minus the output when all inputs are set to 0s.
Output Compliance Range
S/N is the ratio of the rms value of the measured output 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.
Passband
The range of allowable voltage at the output of a current-output
DAC. Operation beyond the maximum compliance limits may
cause either output stage saturation or breakdown, resulting in
nonlinear performance.
Temperature Drift
Frequency band in which any input applied therein passes
unattenuated to the DAC output.
Stopband Rejection
Temperature drift is specified as the maximum change from the
ambient (25°C) value to the value at either T
MIN
or T
MAX
. For
offset and gain drift, the drift is reported in ppm of full-scale
range (FSR) per
°C.
For reference drift, the drift is reported in
ppm per
°C.
Power Supply Rejection
The amount of attenuation of a frequency outside the passband
applied to the DAC, relative to a full-scale signal applied at the
DAC input within the passband.
Group Delay
Number of input clocks between an impulse applied at the
device input and peak DAC output current.
Impulse Response
The maximum change in the full-scale output as the supplies
are varied from minimum to maximum specified voltages.
Response of the device to an impulse applied to the input.
Adjacent Channel Power Ratio (or ACPR)
A ratio in dBc between the measured power within a channel
relative to its adjacent channel.
HP8130
PULSE GENERATOR
EXT. INPUT
CH1
FROM HP8644A
SIGNAL GENERATOR
CH2
3.3V
1k
RESET
MOD0
MOD1
PLLLOCK
DIV0
CLKVDD
CLKCOM
CLK+
AD9772A
DIV1
1k
PLLCOM
LPF
PLLVDD
TO FSEA30
SPECTRUM
MINI-CIRCUITS ANALYZER
T1–1T
100
I
OUTB
0.1 F
REFIO
FSADJ
1.91k
CLK–
1
AWG2021
OR
DG2020
EXT.
CLOCK
1 /2
CLOCK DISTRIBUTION
AND MODE SELECT
FILTER
MUX
CONTROL
CONTROL
PLLCLOCK
MULTIPLIER
2 /4
I
OUTA
DIGITAL
DATA
EDGE-
TRIGGERED
LATCHES
2 FIR
INTERPOLATION
FILTER
ZERO
STUFF
MUX
14-BIT DAC
SLEEP
DCOM
DVDD
3.3V
ACOM AVDD
3.3V
+1.2V REFERENCE
AND CONTROL AMP
REFLO
50
50
20pF
20pF
Figure 3. Basic AC Characterization Test Setup
–8–
REV. A
AD [ ANALOG DEVICES ]
