Test
Parameter 
Unit 
Typical Description 
Resolution 
Bits 
If an
ADC has n bits, then its resolution is 2^{n}, which is
the number of states or codes that it can divide (or "resolve")
the analog input into. The higher the number of bits, the better
is the resolution of the ADC, and the more precise the
representation of each state will be.

Unipolar Offset 
LSB 
The
first transition of an ADC should occur at an analog value that
is 1/2 LSB above the analog common. The deviation of the
ADC's actual first transition from this ideal level is known as
the unipolar offset.
Example of an Actual Spec: +/ 1 LSB max 
Bipolar Offset or
Bipolar Zero Error 
LSB 
In the
bipolar mode, the major carry transition from '011111111111' to
'100000000000' should occur at an analog input value that is 1/2
LSB below the analog common. The deviation of the actual value
of this transition at 25 deg C from the ideal level is known as
the Bipolar Offset or Bipolar Zero Error.
Example of an Actual Spec: +/ 1 LSB max 
NonLinearity, Differential (DNL) 
Bits
(with
no missing codes) 
In an
ADC, code transitions are 1 LSB apart. Maximum deviation
from this ideal value is known as differential nonlinearity. It
is often expressed in terms of the number of bits guaranteed to
have no missing codes.
Example of an Actual Spec: 10 Bits min 
NonLinearity, Integral (INL) 
LSB 
The
transfer function of an ADC is a straight line from "zero" to
"full scale". The maximum deviation of a code from this
straight line is the ADC's integral nonlinearity.
Example of an Actual Spec: +/ 2 LSB's max 
Analog
Input Range or FullScale Range 
V 
This
is the difference between the maximum and minimum analog input
values specified for the ADC.
Examples of Actual Specs:
0V to
+10 V, Unipolar Mode;
5V to
+5V, Bipolar Mode 
Logic
Output
(Current Sink) 
mA 
This
is the amount of current that the digital output of an ADC can
sink when it is at Logic "0".
Example of an Actual Spec:
3.2 mA
when Vout = 0.4V max 
Logic
Output
(Current Source) 
mA 
This
is the amount of current that the digital output of an ADC can
source when it is at Logic "1".
Example of an Actual Spec:
0.5 mA
when Vout = 2.4V max 
Logic
Input Voltage
(Logic
"1") 
V 
This
is the minimum voltage that the digital inputs of the ADC are
guaranteed to recognize as a Logic "1".
Example of an Actual Spec: 2.0 V min. 
Logic
Input Voltage
(Logic
"0") 
V 
This
is the maximum voltage that the digital inputs of the ADC are
guaranteed to recognize as a Logic "0".
Example of an Actual Spec: 0.8 V max. 
Conversion Time 
µsec 
This
is the time required by an ADC to make a complete measurement.
Example of an Actual Spec:
15
µsec min.; 25 µsec typ.; 40 µsec max. 
+
Power Supply (V+) 
V 
This
is the voltage range that can be used for the positive supply of
the ADC.
Example of an Actual Spec:
+4.5V
min.; +5.0V typ.; +7.0V max. 

Power Supply (V) 
V 
This
is the voltage range that can be used for the negative supply of
the ADC.
Example of an Actual Spec:
12.0V
min.; 15V typ.; 16.5V max. 
Analog
Input Impedance 
kW 
This
is the dynamic load presented by an ADC to its analog input
source.
Example of an Actual Spec:
3
kW
min.; 5
kW
typ.; 7
kW
max. 
Gain
Error 
LSB 
This
is the deviation of the actual difference between the first and
last transitions of an ADC from the ideal difference between its
first and last transitions. The last transition of the ADC
should occur at an analog input value that is 1.5 LSB's below
the nominal full scale.
Example of an Actual Spec:
+/ 2
LSB's typ.; +/4 LSB's max. 
Power
Supply Rejection 
LSB 
This
is the maximum change in the fullscale transition point of the
ADC due to a deviation of its power supply voltage from its
nominal value. This is measured at fullscale.
Examples of Actual Specs:
+/ 1
LSB max for V+ = +4.5V to +5.5V;
+/ 1
LSB max for V = 12.6V to 11.4V 
SignaltoNoise Ratio (SNR) 
dB 
This
is the ratio of the measured signal at the output of the ADC to
the measured noise. 'Signal' is the RMS magnitude of the
fundamental signal while noise is the RMS sum of all
nonfundamental signals up to half the sampling frequency,
excluding the DC signal.
Example of an Actual Spec:
44 dB
typ. for Fin=1 MHz and Ain=+/1V 
Total
Harmonic Distortion (THD) 
% or
dB 
This
is the ratio of the rms sum of the first six harmonic components
to the rms value of a fullscale input signal, expressed either
in % or dB. The aliased component is used for input signals or
harmonics that are above the Nyquist frequency. The Nyquist
frequency is the input signal frequency that is 1/2 the sampling
frequency of the ADC.
Examples of Actual Specs:
88 dB
typ.; 80 dB max.
0.004%
typ.; 0.010% max. 