AD5398A

Rev. 0 | Page 9 of 16

TERMINOLOGY

Relative Accuracy

For the DAC, relative accuracy or integral nonlinearity is a

measurement of the maximum deviation, in LSB, from a

straight line passing through the endpoints of the DAC transfer

function. A typical INL vs. code plot is shown in Figure 5.

Differential Nonlinearity

(DNL)

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

ensures monotonicity. This DAC is guaranteed monotonic by

design. A typical DNL vs. code plot is shown in Figure 6.

Zero-Code Error

Zero-code error is a measurement of the output error when

zero code (0x0000) is loaded to the DAC register. Ideally, the

output is 0 mA. The zero-code error is always positive in the

AD5398A because the output of the DAC cannot go below

0 mA. This is due to a combination of the offset errors in the

DAC and output amplifier. Zero-code error is expressed in mA.

Gain Error

This is a measurement of the span error of the DAC. It is the

deviation in slope of the DAC transfer characteristic from the

ideal, expressed as a percent of the full-scale range.

Gain Error Drift

This is a measurement of the change in gain error with changes

in temperature. It is expressed in LSB/°C.

Digital-to-Analog Glitch Impulse

Digital-to-analog glitch impulse is the impulse injected into the

analog output when the input code in the DAC register changes

state. It is normally specified as the area of the glitch in nA-sec

and is measured when the digital input code is changed by

1 LSB at the major carry transition.

Digital Feedthrough

Digital feedthrough is a measurement of the impulse injected

into the analog output of the DAC from the digital inputs of

the DAC, however is measured when the DAC output is not

updated. It is specified in nA-sec and measured with a full-

scale code change on the data bus, that is, from all 0s to all 1s

and vice versa.

Offset Error

function, expressed in mA. Offset error is measured on the

AD5398A with Code 16 loaded into the DAC register.

Offset Error Drift

This is a measurement of the change in offset error with a

change in temperature. It is expressed in μV/°C.