ADT7516/ADT7517/ADT7519
Analog Crosstalk
Analog crosstalk is the glitch impulse transferred to the output
of one DAC due to a change in the output of another 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
DAC-to-DAC crosstalk 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
LDAC low and monitoring the output of another DAC. The
energy of the glitch is expressed in nV-s.
Multiplying Bandwidth
The multiplying bandwidth is a measure of the finite bandwidth
of the amplifiers within the DAC. 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)
THD 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, expressed in dB.
Round Robin
The term round robin is used to describe the ADT7516/ADT7517/
ADT7519 cycling through the available measurement channels
in sequence, taking a measurement on each channel.
DAC Output Settling Time
DAC output settling time is the time required, following a
prescribed data change, for the output of a DAC to reach and
remain within ±0.5 LSB of the final value. A typical prescribed
change is from 1/4 scale to 3/4 scale.
OUTPUT
VOLTAGE
GAIN ERROR
+
OFFSET ERROR
NEGATIVE
OFFSET
ERROR
DAC CODE
ACTUAL
IDEAL
AMPLIFIER
FOOTROOM
LOWER
DEADBAND
CODES
NEGATIVE
OFFSET
ERROR
Figure 40. DAC Transfer Function with Negative Offset
OUTPUT
VOLTAGE
GAIN ERROR
+
OFFSET ERROR
UPPER
DEADBAND
CODES
ACTUAL
IDEAL
POSITIVE
OFFSET
ERROR
DAC CODE
FULL-SCALE
Figure 41. DAC Transfer Function with Positive Offset (VREF = VDD)
Rev. B | Page 18 of 44