AD420

Rev. H | Page 8 of 16

TERMINOLOGY

Resolution

For 16-bit resolution, 1 LSB = 0.0015% of the FSR. In the

4 mA–20 mA range 1 LSB = 244 nA.

Integral Nonlinearity

Analog Devices defines integral nonlinearity as the maximum

deviation of the actual, adjusted DAC output from the ideal

analog output (a straight line drawn from 0 to FS – 1 LSB) for

any bit combination. This is also referred to as relative accuracy.

Differential Nonlinearity

Differential nonlinearity is the measure of the change in the

analog output, normalized to full scale, associated with an LSB

change in the digital input code. Monotonic behavior requires

that the differential linearity error be greater than –1 LSB over

the temperature range of interest.

Monotonicity

A DAC is monotonic if the output either increases or remains

constant for increasing digital inputs with the result that the

output will always be a single-valued function of the input.

Gain Error

Gain error is a measure of the output error between an ideal

DAC and the actual device output with all 1s loaded after offset

error has been adjusted out.

Offset Error

Offset error is the deviation of the output current from its ideal

value expressed as a percentage of the fullscale output with all

0s loaded in the DAC.

Drift

Drift is the change in a parameter (such as gain and offset) over

a specified temperature range. The drift temperature coefficient,

specified in ppm/°C, is calculated by measuring the parameter

parameter by the corresponding temperature change.

Current Loop Voltage Compliance

which the output current will be equal to the programmed value.