DAC8565ICPWG4 Datasheet, PDF (40/49 Pages) Texas Instruments – 16-Bit, Quad Channel, Ultra-Low Glitch, Voltage Output

DAC8565
SBAS411C – JUNE 2007 – REVISED MARCH 2011
Power-Supply Rejection Ratio (PSRR)
Power-supply rejection ratio (PSRR) is defined as the
ratio of change in output voltage to a change in
supply voltage for a full-scale output of the DAC. The
PSRR of a device indicates how the output of the
DAC is affected by changes in the supply voltage.
PSRR is measured in decibels (dB).
Monotonicity
Monotonicity is defined as a slope whose sign does
not change. If a DAC is monotonic, the output
changes in the same direction or remains at least
constant for each step increase (or decrease) in the
input code.
DYNAMIC PERFORMANCE
Dynamic performance parameters are specifications
such as settling time or slew rate, which are important
in applications where the signal rapidly changes
and/or high frequency signals are present.
Slew Rate
The output slew-rate (SR) of an amplifier or other
electronic circuit is defined as the maximum rate of
change of the output voltage for all possible input
signals.
SR = max
DV_OUT(t)
Dt
Where ΔV_OUT(t) is the output produced by the
amplifier as a function of time t.
Output Voltage Settling Time
Settling time is the total time (including slew time) for
the DAC output to settle within an error band around
its final value after a change in input. Settling times
are specified to within ±0.003% (or whatever value is
specified) of full-scale range (FSR).
Code Change/Digital-to-Analog Glitch Energy
Digital-to-analog glitch impulse is the impulse injected
into the analog output when the input code in the
DAC register changes state. It is normally specified
as the area of the glitch in nanovolts-second (nV-s),
and is measured when the digital input code changes
by 1LSB at the major carry transition.
Digital Feedthrough
Digital feedthrough is defined as impulse seen at the
output of the DAC from the digital inputs of the DAC.
It is measured when the DAC output is not updated. It
is specified in nV-s, and measured with a full-scale
code change on the data bus; that is, from all '0's to
all '1's and vice versa.
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Channel-to-Channel DC Crosstalk
Channel-to-channel dc crosstalk is defined as the dc
change in the output level of one DAC channel in
response to a change in the output of another DAC
channel. It is measured with a full-scale output
change on one DAC channel while monitoring
another DAC channel remains at midscale. It is
expressed in LSB.
Channel-to-Channel AC Crosstalk
AC crosstalk in a multi-channel DAC is defined as the
amount of ac interference experienced on the output
of a channel at a frequency (f) (and its harmonics),
when the output of an adjacent channel changes its
value at the rate of frequency (f). It is measured with
one channel output oscillating with a sine wave of
1kHz frequency, while monitoring the amplitude of
1kHz harmonics on an adjacent DAC channel output
(kept at zero scale). It is expressed in dB.
Signal-to-Noise Ratio (SNR)
Signal-to-noise ratio (SNR) is defined as the ratio of
the root mean-squared (RMS) value of the output
signal divided by the RMS values of the sum of all
other spectral components below one-half the output
frequency, not including harmonics or dc. SNR is
measured in dB.
Total Harmonic Distortion (THD)
Total harmonic distortion + noise is defined as the
ratio of the RMS values of the harmonics and noise
to the value of the fundamental frequency. It is
expressed in a percentage of the fundamental
frequency amplitude at sampling rate f_S.
Spurious-Free Dynamic Range (SFDR)
Spurious-free dynamic range (SFDR) is the usable
dynamic range of a DAC before spurious noise
interferes or distorts the fundamental signal. SFDR is
the measure of the difference in amplitude between
the fundamental and the largest harmonically or
non-harmonically related spur from dc to the full
Nyquist bandwidth (half the DAC sampling rate, or
f_S/2). A spur is any frequency bin on a spectrum
analyzer, or from a Fourier transform, of the analog
output of the DAC. SFDR is specified in decibels
relative to the carrier (dBc).
Signal-to-Noise plus Distortion (SINAD)
SINAD includes all the harmonic and outstanding
spurious components in the definition of output noise
power in addition to quantizing any internal random
noise power. SINAD is expressed in dB at a specified
input frequency and sampling rate, f_S.
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