AD5675 Datasheet, PDF (17/27 Pages) Analog Devices – Base station power amplifiers

AD5675
Data Sheet
TERMINOLOGY
Relative Accuracy or Integral Nonlinearity (INL)
For a DAC, relative accuracy or integral nonlinearity is a
measurement of the maximum deviation, in LSBs, from a
straight line passing through the endpoints of the DAC transfer
function.
Differential Nonlinearity (DNL)
DNL is the difference between the measured change and the
ideal 1 LSB change between any two adjacent codes. A specified
DNL of ±1 LSB maximum ensures monotonicity. This DAC is
guaranteed monotonic by design.
Zero Code Error
Zero code error is a measurement of the output error when zero
code (0x0000) is loaded to the DAC register. The ideal output is
0 V. The zero code error is always positive because the output of
the DAC cannot go below 0 V due to a combination of the offset
errors in the DAC and the output amplifier. Zero code error is
expressed in mV.
Digital Feedthrough
Digital feedthrough is a measure of the impulse injected intothe
analog output of the DAC from the digital inputs of the DAC,
but is measured when the DAC output is not updated. It is
specified in nV-sec, and measured with a full-scale code change
on the data bus, that is, from all 0s to all 1s and vice versa.
Noise Spectral Density (NSD)
NSD is a measurement of the internally generated random
noise. Random noise is characterized as spectral density
(nV/√Hz). To measure NSD, load the DAC to midscale and
measure the noise at the output. It is measured in nV/√Hz.
DC Crosstalk
DC crosstalk is the dc change in the output level of one DAC in
response to a change in the output of another DAC. It is measured
with a full-scale output change on one DAC (or soft power-down
and power-up) while monitoring another DAC kept at midscale.
It is expressed in μV.
Full-Scale Error
Full-scale error is a measurement of the output error when full-
scale code (0xFFFF) is loaded to the DAC register. The ideal
output is VDD − 1 LSB. Full-scale error is expressed in percent of
full-scale range (% of FSR).
Gain Error
Gain error is a measure of the span error of a DAC. It is the
deviation in slope of the DAC transfer characteristic from the
ideal expressed as % of FSR.
DC crosstalk due to load current change is a measure of the
impact that a change in load current on one DAC has on
another DAC kept at midscale. It is expressed in μV/mA.
Digital Crosstalk
Digital crosstalk 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 measured in standalone mode and is expressed in
nV-sec.
Offset Error Drift
Offset error drift is a measurement of the change in offset error
with a change in temperature. It is expressed in µV/°C.
Offset Error
Offset error is a measure of the difference between VOUT (actual)
and VOUT (ideal) expressed in mV in the linear region of the
transfer function. Offset error is measured with Code 256
loaded in the DAC register. It can be negative or positive.
DC Power Supply Rejection Ratio (PSRR)
The dc PSRR indicates how the output of the DAC is affected by
changes in the supply voltage. PSRR is the ratio of the change in
VOUT to the change in VDD for the full-scale output of the DAC.
It is measured in mV/V. VREF is held at 2 V, and VDD is varied by
±10%.
Output Voltage Settling Time
The output voltage settling time is the amount of time it takes
for the output of a DAC to settle to a specified level for a ¼ to ¾
full-scale input change.
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. To
measure analog crosstalk, first load one of the input registers
with a full-scale code change (all 0s to all 1s and vice versa).
Then, execute a software LDAC and monitor the output of the
DAC whose digital code was not changed. The area of the glitch
is expressed in nV-sec.
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
analog output change of another DAC. It is measured by
loading the attack channel with a full-scale code change (all 0s
to all 1s and vice versa), using the write to and updatecommands
while monitoring the output of the victim channel that is at
midscale. The energy of the glitch is expressed in nV-sec.
Digital-to-Analog Glitch Impulse
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 nV-sec,
and is measured when the digital input code is changed by
1 LSB at the major carry transition (0x7FFF to 0x8000).
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