Datasheet

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SR max
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DAC5578
DAC6578
DAC7578
SBAS496A –MARCH 2010–REVISED AUGUST 2010 www.ti.com
Monotonicity Digital Feed-through
Monotonicity is defined as a slope whose sign does Digital feed-through is defined as impulse seen at the
not change. If a DAC is monotonic, the output output of the DAC from the digital inputs of the DAC.
changes in the same direction or remains at least It is measured when the DAC output is not updated. It
constant for each step increase (or decrease) in the is specified in nV-s, and measured with a full-scale
input code. code change on the data bus; that is, from all '0's to
all '1's and vice versa.
DYNAMIC PERFORMANCE
Channel-to-Channel DC Crosstalk
Dynamic performance parameters are specifications
Channel-to-channel dc crosstalk is defined as the dc
such as settling time or slew rate, which are important
change in the output level of one DAC channel in
in applications where the signal rapidly changes
response to a change in the output of another DAC
and/or high frequency signals are present.
channel. It is measured with a full-scale output
change on one DAC channel while monitoring
Slew Rate
another DAC channel remains at midscale. It is
The output slew rate (SR) of an amplifier or other
expressed in LSB.
electronic circuit is defined as the maximum rate of
DAC Output Noise Density
change of the output voltage for all possible input
signals.
Output noise density is defined as
internally-generated random noise. Random noise is
characterized as a spectral density (nV/√Hz). It is
measured by loading the DAC to midscale and
measuring noise at the output.
Where ΔV
OUT
(t) is the output produced by the
DAC Output Noise
amplifier as a function of time t.
DAC output noise is defined as any voltage deviation
Output Voltage Settling Time
of DAC output from the desired value (within a
Settling time is the total time (including slew time) for
particular frequency band). It is measured with a DAC
the DAC output to settle within an error band around
channel kept at midscale while filtering the output
its final value after a change in input. Settling times
voltage within a band of 0.1Hz to 10Hz and
are specified to within ±0.003% (or whatever value is
measuring its amplitude peaks. It is expressed in
specified) of full-scale range (FSR).
terms of peak-to-peak voltage (Vpp).
Code Change/Digital-to-Analog Glitch Energy
Full-Scale Range (FSR)
Digital-to-analog glitch impulse is the impulse injected
Full-scale range (FSR) is the difference between the
into the analog output when the input code in the
maximum and minimum analog output values that the
DAC register changes state. It is normally specified
DAC is specified to provide; typically, the maximum
as the area of the glitch in nanovolt-seconds (nV-s),
and minimum values are also specified. For an n-bit
and is measured when the digital input code is
DAC, these values are usually given as the values
changed by 1LSB at the major carry transition.
matching with code 0 and 2
n
–1.
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