AD7538
Rev. B | Page 8 of 16
TERMINOLOGY
Relative Accuracy
Relative accuracy or endpoint nonlinearity is a measure of the
maximum deviation from a straight line passing through the
endpoints of the DAC transfer function. It is measured after
adjusting for zero error and full-scale error and is normally
expressed in least significant bits or as a percentage of full-
scale reading.
Differential Nonlinearity
Differential nonlinearity is the difference between the measured
change and the ideal 1 LSB change between any two adjacent
codes. A specified differential nonlinearity of ±1 LSB maximum
over the operating temperature range ensures monotonicity.
Gain Error
Gain error is a measure of the output error between an ideal
DAC and the actual device output. It is measured with all 1s
in the DAC after the offset error has been adjusted out and is
expressed in least significant bits. Gain error is adjustable to
zero with an external potentiometer.
Digital-To-Analog Glitch Impulse
The amount of charge injected from the digital inputs to the
analog output when the inputs change state is called digital-to-
analog glitch impulse. This is normally specified as the area of
the glitch in either pA-secs or nV-secs depending upon whether
the glitch is measured as a current or voltage. It is measured
with V
REF
= AGND.
Output Capacitance
This is the capacitance from I
OUT
to AGND.
Output Leakage Current
Output leakage current is current which appears at I
OUT
with the
DAC register loaded to all 0s.
Multiplying Feedthrough Error
This is the ac error due to capacitive feedthrough from the V
REF
terminal to I
OUT
with the DAC register loaded to all zeros.
