Datasheet

DS1868B
ABSOLUTE AND RELATIVE LINEARITY
Absolute linearity, also known as Integral Nonlinearity, is defined as the difference between the actual
measured output voltage and the expected output voltage. Figure 5 presents the test circuit used to
measure absolute linearity. Absolute linearity is given in terms of a minimum increment or expected
output when the wiper is moved one position. In the case of the test circuit, a minimum increment (MI) or
one LSB would equal 5/256V. The equation for absolute linearity is given as follows:
(1) ABSOLUTE LINEARITY (INL)
AL={V
O
(actual) - V
O
(expected)}/MI
Relative linearity, also known as Differential Nonlinearity, is a measure of error between two adjacent
wiper position points and is given in terms of MI by equation (2).
(2) RELATIVE LINEARITY (DNL)
RL={V
O
(n+1) - V
O
(n)}/MI
Figure 6 is a plot of absolute linearity and relative linearity versus wiper position for the DS1868B at
25°C. The specification for absolute linearity of the DS1868B is ±0.75 MI typical. The specification for
relative linearity of the DS1868B is ±0.3 MI typical.
LINEARITY MEASUREMENT CONFIGURATION Figure 5
Maxim Integrated ............................................................................................................................................................................................. 5