HI5760
either T
range) per degree C.
or T
. The units are ppm of FSR (full scale
Definition of Specifications
MIN
MAX
Integral Linearity Error, INL, is the measure of the worst
case point that deviates from a best fit straight line of data
values along the transfer curve.
Power Supply Rejection, is measured using a single power
supply. Its nominal +5V is varied ±10% and the change in the
DAC full scale output is noted.
Differential Linearity Error, DNL, is the measure of the
step size output deviation from code to code. Ideally the step
size should be 1 LSB. A DNL specification of 1 LSB or less
guarantees monotonicity.
Reference Input Multiplying Bandwidth, is defined as the
3dB bandwidth of the voltage reference input. It is measured
by using a sinusoidal waveform as the external reference
with the digital inputs set to all 1s. The frequency is
increased until the amplitude of the output waveform is 0.707
of its original value.
Output Settling Time, is the time required for the output
voltage to settle to within a specified error band measured
from the beginning of the output transition. In the case of the
HI5760, the measurement was done by switching from code
0 to 256, or quarter scale. Termination impedance was 25Ω
due to the parallel resistance of the output 50Ω and the
oscilloscope’s 50Ω input. This also aids the ability to resolve
the specified error band without overdriving the oscilloscope.
Internal Reference Voltage Drift, is defined as the
maximum deviation from the value measured at room
temperature to the value measured at either Tmin or Tmax.
The units are ppm per degree C.
Detailed Description
Singlet Glitch Area, is the switching transient appearing on
the output during a code transition. It is measured as the
area under the overshoot portion of the curve and is
expressed as a Volt-Time specification.
The HI5760 is a 10-bit, current out, CMOS, digital to analog
converter. Its maximum update rate is 125MSPS and can be
powered by either single or dual power supplies in the
recommended range of +3V to +5V. It consumes less than
165mW of power when using a +5V supply with the data
switching at 100MSPS. The architecture is based on a
segmented current source arrangement that reduces glitch
by reducing the amount of current switching at any one time.
The five MSBs are represented by 31 major current sources
of equivalent current. The five LSBs are comprised of binary
weighted current sources. Consider an input waveform to the
converter which is ramped through all the codes from 0 to
1023. The five LSB current sources would begin to count up.
When they reached the all high state (decimal value of 31)
and needed to count to the next code, they would all turn off
and the first major current source would turn on. To continue
counting upward, the 5 LSBs would count up another 31
codes, and then the next major current source would turn on
and the five LSBs would all turn off. The process of the
single, equivalent, major current source turning on and the
five LSBs turning off each time the converter reaches
another 31 codes greatly reduces the glitch at any one
switching point. In previous architectures that contained all
binary weighted current sources or a binary weighted
resistor ladder, the converter might have a substantially
larger amount of current turning on and off at certain, worst-
case transition points such as mid-scale and quarter scale
transitions. By greatly reducing the amount of current
switching at certain ‘major’ transitions, the overall glitch of
the converter is dramatically reduced, improving settling
times and transient problems.
Full Scale Gain Error, is the error from an ideal ratio of 32
between the output current and the full scale adjust current
(through R
).
SET
Full Scale Gain Drift, is measured by setting the data inputs
to all ones and measuring the output voltage through a
known resistance as the temperature is varied from T
to
MIN
T
. It is defined as the maximum deviation from the value
MAX
measured at room temperature to the value measured at
either T or T . The units are ppm of FSR (full scale
MIN
MAX
range) per degree C.
Total Harmonic Distortion, THD, is the ratio of the DAC
output fundamental to the RMS sum of the first five
harmonics.
Spurious Free Dynamic Range, SFDR, is the amplitude
difference from the fundamental to the largest harmonically or
non-harmonically related spur within the specified window.
Output Voltage Compliance Range, is the voltage limit
imposed on the output. The output impedance load should
be chosen such that the voltage developed does not violate
the compliance range.
Offset Error, is measured by setting the data inputs to all
zeros and measuring the output voltage through a known
resistance. Offset error is defined as the maximum deviation
of the output current from a value of 0mA.
Offset Drift, is measured by setting the data inputs to all
zeros and measuring the output voltage through a known
resistance as the temperature is varied from T
to T
.
MAX
MIN
It is defined as the maximum deviation from the value
measured at room temperature to the value measured at
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