AD5304/AD5314/AD5324 Data Sheet
Rev. H | Page 12 of 24
TERMINOLOGY
Relative Accuracy or Integral Nonlinearity (INL)
For the DAC, relative accuracy or integral nonlinearity (INL)
is a measure of the maximum deviation, in LSB, from a straight
line passing through the endpoints of the DAC transfer function.
Typical INL vs. code plots can be seen in Figure 5, Figure 6,
and Figure 7.
Differential Nonlinearity
Differential nonlinearity (DNL) is the difference between the
measured change and the ideal 1 LSB change between any two
adjacent codes. A specified differential nonlinearity of ±1 LSB
maximum ensures monotonicity. This DAC is guaranteed mono-
tonic by design. Typical DNL vs. code plots can be seen in Figure 8,
Figure 9, and Figure 10.
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 deviation
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.
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%.
DC Crosstalk
This is the dc change in the output level of one DAC at midscale
in response to a full-scale code change (all 0s to all 1s and vice
versa) and output change of another DAC. It is expressed in
microvolts.
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.
It is expressed in decibels.
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 when the DAC output is not being written to (
SYNC
held high). It is specified in nV-s and is measured with a worst-
case change on the digital input pins (for example, from all 0s
to all 1s or vice versa.)
Digital Crosstalk
This is the glitch impulse transferred to the output of one DAC
at midscale in response to a full-scale code change (all 0s to all
1s and vice versa) in the input register of another DAC. It 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
another 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) with the
LDAC
bit set low
and monitoring the output of another DAC. The energy of the
glitch is expressed in nV-s.
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.
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.
