AD±±70
TERMINOLOGY
Relative Accuracy or Integral Nonlinearity (INL)
Output Voltage Settling Time
Relative accuracy or integral nonlinearity is a measure of the
maximum deviation, in LSBs, from a straight line passing
through the endpoints of the DAC transfer function.
Output voltage settling time is the amount of time it takes for
the output to settle to a specified level for a full-scale input
change.
Monotonicity
Slew Rate
A DAC is monotonic, if the output either increases or remains
constant for increasing digital inputs. The AD5570 is monotonic
over its full operating temperature range.
The slew rate of a device is a limitation in the rate of change of
output voltage. The output slewing speed of a voltage-output
D/A converter is usually limited by the slew rate of the amplifier
used at its output. Slew rate is measured from 10ꢂ to 90ꢂ of the
output signal and is given in V/µs.
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 differential nonlinearity of 1 LSB maximum
ensures monotonicity.
Digital-to-Analog Glitch Impulse
Digital-to-analog glitch impulse is the amount of charge in-
jected into the analog output when the input codes in the DAC
register change state. It is specified as the area of the glitch in
nV-s and is measured when the digital input code changes by
1 LSB at the major carry transition, that is, from code 0x7FFF to
0x8000.
Gain Error
Gain error is the difference between the actual and ideal analog
output range, expressed as a percent of the full-scale range. It is
the deviation in slope of the DAC transfer characteristic from
the ideal.
Bandwidth
The reference amplifiers within the DAC have a finite band-
width to optimize noise performance. To measure it, a sine
wave is applied to the reference input (REFIN), with full-scale
code loaded to the DAC. The bandwidth is the frequency at
which the output amplitude falls to 3 dB below the input.
Gain Error Temperature Coefficient
Gain error temperature coefficient is a measure of the change in
gain error with changes in temperature. It is expressed in
ppm/°C.
Digital Feedthrough
Negative Full-Scale Error / Zero Scale Error
Digital feedthrough is a measure of the impulse injected into
the analog output of the DAC from the digital inputs of the
DAC, but is measured when the DAC output is not updated.
Negative full-scale error is the error in the DAC output voltage
when all 0s are loaded into the DAC latch. Ideally, the output
voltage, with all 0s in the DAC latch, should be −ꢀ VREF
.
is held high, while the CLK and SDIN signals are toggled.
SYNC
Full-Scale Error
It is specified in nV-s and is measured with a full-scale code
change on the data bus, that is, from all 0s to all 1s and vice
versa.
Full-scale error is the error in the DAC output voltage when all
1s are loaded to the DAC latch. Ideally the output voltage, with
all 1s loaded into the DAC latch, should be ꢀ VREF − 1 LSB.
Power Supply Sensitivity
Bipolar Zero Error
Power supply sensitivity indicates how the output of the DAC is
affected by changes in the power supply voltage.
Bipolar zero error is the deviation of the analog input from the
ideal half-scale output of 0.0000 V when the inputs are loaded
with 0x8000.
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