Differential Nonlinearity: Ideally, any two adjacent digital
codes correspond to output analog voltages that are exactly
one LSB apart. Differential non-linearity is a measure of the
worst case deviation from the ideal 1 LSB step. For example,
a DAC with a 1.5 LSB output change for a 1 LSB digital code
change exhibits 1⁄2 LSB differential non-linearity. Differential
non-linearity may be expressed in fractional bits or as a percentage
of full scale. A differential non-linearity greater than
1 LSB will lead to a non-monotonic transfer function in a
DAC.
Gain Error (Full Scale Error): The difference between the
output voltage (or current) with full scale input code and the
ideal voltage (or current) that should exist with a full scale input
code.
Gain Temperature Coefficient (Full Scale Temperature
Coefficient): Change in gain error divided by change in temperature.
Usually expressed in parts per million per degree
Celsius (ppm/°C).
Integral Nonlinearity (Linearity Error): Worst case deviation
from the line between the endpoints (zero and full scale).
Can be expressed as a percentage of full scale or in fraction
of an LSB.
LSB (Lease-Significant Bit): In a binary coded system this
is the bit that carries the smallest value or weight. Its value is
the full scale voltage (or current) divided by 2n, where n is the
resolution of the converter.
Monotonicity: A monotonic function has a slope whose sign
does not change. A monotonic DAC has an output that
changes in the same direction (or remains constant) for each
increase in the input code. the converse is true for decreasing codes.
