|
Test
Parameter |
Unit |
Typical Description |
|
Resolution |
Bits |
This is the
number of bits that the DAC has. If a DAC has n bits, then its output
analog signal span can be divided (or "resolved") into 2n
states, each corresponding to its own digital input code. The higher
the number of bits, the better is the resolution of a DAC. |
|
Voltage
Reference Input Range |
V |
This indicates
the minimum and maximum voltages that may be used as the DAC's external
reference voltage.
Example of an Actual Spec: 0V min; Vdd max
|
|
Bipolar Zero Error or Midscale
Error |
mV |
This is the
deviation of the actual analog output of the DAC from the ideal output of
0V when the 2's complement input code representing half-scale (all zeros)
is loaded into the input register.
Example of an
Actual Spec: +/- 30 mV typ. |
|
Non-Linearity,
Differential (DNL) |
LSB or
% of FSR |
This is the
difference between the actual or measured output change and the ideal
output change for a digital input change of 1 LSB, i.e., for a transition
between two adjacent codes.
Examples of
Actual Specs:
+/- 1 LSB; +/- 0.001% FSR
typ. |
|
Non-Linearity, Integral
(INL)
or Relative
Accuracy |
LSB |
This is the
maximum deviation of the output from the straight line between the zero
and full-scale points, excluding the effects of zero and full-scale
errors.
Example of an
Actual Spec:
+/-1 LSB typ.;
+/- 4 LSB's max. |
|
Analog Output
Range or Full-Scale Range |
V
|
This is the
difference between the maximum and minimum analog output values that the
DAC is specified to provide.
Example of
Actual Spec: -3V to +3V,
Bipolar Mode |
|
Logic Input
Voltage, Vih
(Logic "1") |
V |
This is the
minimum voltage that the digital inputs of the DAC are guaranteed to recognize as a
Logic "1".
Example of an
Actual Spec: 2.4 V min. |
|
Logic Input
Voltage, Vil
(Logic "0") |
V |
This is the
maximum voltage that the digital inputs of the DAC are guaranteed to recognize as a
Logic "0".
Example of an
Actual Spec: 0.8 V max. |
|
Input Leakage
Current, IIL |
µA |
This is maximum
leakage current exhibited by a digital input at logic "0".
Example of an
Actual Spec: 2 µA
max. for Vil =
0.4 V. |
|
Settling
Time |
µsec |
This is
the time required by the outputs of a DAC to reach and remain within a
specified error band about its final value. This is measured from the
digital input transition.
Examples of
Actual Specs:
1.5 µsec typ.
for a 6V step;
1.0 µsec typ.
for a 1 LSB step; |
|
Analog Positive Power Supply
(+Vs) |
V |
This is the
voltage range that can be used for the analog positive supply of the DAC.
Example of an
Actual Spec:
+4.75V
min.; +5.0V typ.; +13.2V
max. |
|
Analog Negative
Power Supply (-Vs) |
V |
This is the
voltage range that can be used for the analog negative supply of the DAC.
Example of an
Actual Spec:
-13.2V
min.; -5V typ.; -4.75V
max. |
|
Logic Positive Power Supply
(+VL) |
V |
This is the
voltage range that can be used for the logic positive supply of the DAC.
Example of an
Actual Spec:
+4.75V
min.; +5.0V typ.; +13.2V
max. |
|
Logic Negative
Power Supply (-VL) |
V |
This is the
voltage range that can be used for the logic negative supply of the DAC.
Example of an
Actual Spec:
-13.2V
min.; -5V typ.; -4.75V
max. |
|
Analog Output
Impedance |
kW |
This is the
dynamic load presented by a DAC at its analog output.
Example of an
Actual Spec: 0.1
kW typ. |
|
Gain Error or
Full-Scale
Error |
mV
or %FSR |
This indicates
how closely the analog output of a DAC matches its ideal value at full
scale and may be expressed in mV or as a % of the FSR. For many DAC's, the
ideal maximum output voltage is Vref-1 LSB.
Example of an
Actual Spec: +/-1.22 mV |
|
Signal-to-Noise Ratio (SNR) |
dB |
This is the
ratio of the amplitude of the analog output of the DAC when the output is
set to full-scale to the amplitude of the output when it is set to zero.
Example of an
Actual Spec:
107
dB min.; 110 dB typ.
for 20 Hz-30 kHz |
|
Total Harmonic Distortion (THD) |
dB |
This is the
ratio of the rms sum of the first few (2nd to 6th) harmonic components of
the DAC output to the DAC output's fundamental value, usually expressed in dB.
Example of an Actual Spec: -80 dB typ.
|
