AD5303/AD5313/AD5323
Rev. B | Page 10 of 28
TERMINOLOGY
Relative Accuracy or Integral Nonlinearity (INL)
For the DAC, relative accuracy or integral nonlinearity is a
measure of the maximum deviation, in LSB, from a straight
line passing through the actual endpoints of the DAC transfer
function. A typical INL error vs. code plot can be seen in
Figure 7, Figure 8, and Figure 9.
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between the measured
change and the ideal 1 LSB change between any two adjacent
codes. A specified DNL of ±1 LSB maximum ensures monotonic-
ity. This DAC is guaranteed monotonic by design. A typical
DNL error vs. code plot can be seen in
Figure 10, Figure 11, and
Figure 12.
Offset Error
This is a measure of the offset error of the DAC and the output
amplifier. It is expressed as a percentage of the full-scale range.
Gain Error
This is a measure of the span error of the DAC. It is the devia-
tion in slope of the actual DAC transfer characteristic from the
ideal expressed as a percentage of the full-scale range.
Offset Error Drift
This is a measure of the change in offset error with changes in
temperature. It is expressed in (ppm of full-scale range)/°C.
Gain Error Drift
This is a measure of the change in gain error with changes in
temperature. It is expressed in (ppm of full-scale range)/°C.
Major-Code Transition Glitch Energy
Major-code transition glitch energy is the energy of the impulse
injected into the analog output when the code in the DAC register
changes state. It is normally specified as the area of the glitch in
nV-s and is measured when the digital code is changed by 1 LSB
at the major carry transition (011 . . . 11 to 100 . . . 00 or 100 . . .
00 to 011 . . . 11).
Digital Feedthrough
Digital feedthrough is a measure of the impulse injected into
the analog output of the DAC from the digital input pins of the
device, but is measured when the DAC is not being written to
(
SYNC
held high). It is specified in nV-s and is measured with a
full-scale change on the digital input pins, that is, from all 0s to
all 1s and vice versa.
Analog Crosstalk
This is the glitch impulse transferred to the output of one DAC
due to a change in the output of the other DAC. It is measured
by loading one of the input registers with a full-scale code
change (all 0s to all 1s and vice versa) while keeping
LDAC
high. Then pulse
LDAC
low and monitor the output of the
DAC whose digital code was not changed. The area of the
glitch is expressed in nV-s.
DAC-to-DAC Crosstalk
This is the glitch impulse transferred to the output of one DAC
due to a digital code change and subsequent output change of
the other DAC. This includes both digital and analog crosstalk.
It is measured by loading one of the DACs with a full-scale code
change (all 0s to all 1s and vice versa) while keeping
LDAC
low
and monitoring the output of the other DAC. The area of the
glitch is expressed in nV-s.
DC Crosstalk
This is the dc change in the output level of one DAC in response
to a change in the output of the other DAC. It is measured with
a full-scale output change on one DAC while monitoring the
other DAC. It is expressed in microvolts.
Power Supply Rejection Ratio (PSRR)
This indicates how the output of the DAC is affected by changes
in the supply voltage. PSRR is the ratio of the change in V
OUT
to
a change in V
DD
for full-scale output of the DAC. It is measured
in decibels. V
REF
is held at 2 V and V
DD
is varied ±10%.
Reference Feedthrough
This is the ratio of the amplitude of the signal at the DAC output to
the reference input when the DAC output is not being updated
(that is,
LDAC
is high). It is expressed in decibels.
Total Harmonic Distortion (THD)
This is the difference between an ideal sine wave and its
attenuated version using the DAC. The sine wave is used as
the reference for the DAC and the THD is a measure of the
harmonics present on the DAC output. It is measured in
decibels.
Multiplying Bandwidth
The amplifiers within the DAC have a finite bandwidth. The
multiplying bandwidth is a measure of this. A sine wave on the
reference (with full-scale code loaded to the DAC) appears on
the output. The multiplying bandwidth is the frequency at
which the output amplitude falls to 3 dB below the input.
Channel-To-Channel Isolation
This is a ratio of the amplitude of the signal at the output of one
DAC to a sine wave on the reference input of the other DAC. It
is measured in decibels.
