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Data Sheet

AD5683R/AD5682R/AD5681R/AD5683

Rev. D | Page 17 of 28

TERMINOLOGY

Relative Accuracy or Integral Nonlinearity (INL)

For the DAC, relative accuracy or integral nonlinearity is a

measurement of the maximum deviation, in LSBs, from a straight

line passing through the endpoints of the DAC transfer function.

See Figure 11, Figure 12, and Figure 13 for typical INL vs.

code plots.

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. See Figure 14, Figure 15, and Figure 16 for typical DNL

vs. code plots.

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

must be 0 V. The zero code error is always positive in the

AD5683R/AD5682R/AD5681R because the output of the DAC

cannot fall below 0 V due to a combination of the offset errors

in the DAC and the output amplifier. Zero code error is expressed

in mV. A plot of zero code error vs. temperature is shown in

Figure 24.

Full-Scale Error

Full-scale error is a measurement of the output error when full-

scale code (0xFFFF) is loaded to the DAC register. Ideally, the

output must be VREF – 1 LSB or |2 × VREF| – 1 LSB. Full-scale error is

expressed in percent of full-scale range (% of FSR). See Figure 23

and Figure 26 for plots of full-scale error.

Gain Error

Gain error is a measure of the span error of the DAC. It is the

deviation in slope of the DAC transfer characteristic from the

ideal expressed as % of FSR.

Zero-Code Error Drift

Zero-code error drift is a measurement of the change in zero-

code error with a change in temperature. It is expressed in µV/°C.

Gain Temperature Coefficient

Gain temperature coefficient is a measurement of the change in

gain error with changes in temperature. It is expressed in ppm

of FSR/°C.

Offset Error

Offset error is a measure of the difference between VOUT (actual)

and VOUT (ideal) expressed in mV in the linear region of the

transfer function. Offset error is measured on the AD5683R with

Code 512 loaded in the DAC register. It can be negative or positive.

DC Power Supply Rejection Ratio (PSRR)

PSRR indicates how the output of the DAC is affected by changes

in the supply voltage. PSRR is the ratio of the change in VOUT to

a change in VDD for mid-scale output of the DAC. It is measured

in dB. VREF is held at 2 V, and VDD is varied by ±10%.

Output Voltage Settling Time

Output voltage settling time is the amount of time it takes for

the output of a DAC to settle to a specified level for a ¼ to ¾

scale input change.

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 nV-sec

and is measured when the digital input code is changed by 1 LSB

at the major carry transition (0x7FFF to 0x8000), as shown in

Figure 40.

Digital Feedthrough

Digital feedthrough is a measure of the impulse injected into

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

DAC, but it is measured when the DAC output is not updated.

Digital feedthrough is specified in nV-sec and measured with

a full-scale code change on the data bus, that is, from all 0s to all

1s and vice versa.

Reference Feedthrough

Reference feedthrough is the ratio of the amplitude of the signal

at the DAC output to the reference input when the DAC output

is not being updated. It is expressed in dB.

Output Noise Spectral Density

Noise spectral density is a measurement of the internally generated

random noise. Random noise is characterized as a spectral density

(nV/√Hz). It is measured by loading the DAC to midscale and

measuring noise at the output. It is measured in nV/√Hz. See

Figure 31, Figure 34, and Figure 35 for a plot of noise spectral

density. The noise spectral density for the internal reference is

shown in Figure 30 and Figure 33.

Multiplying Bandwidth

The amplifiers within the DAC have a finite bandwidth. The

multiplying bandwidth is a measure of this finite bandwidth.

A sine wave on the reference (with full-scale code loaded to the

DAC) appears on the output. The multiplying bandwidth is the

frequency at which the output amplitude falls to 3 dB below

the input.

Total Harmonic Distortion (THD)

THD is the difference between an ideal sine wave and the

attenuated version using the DAC. The sine wave is used as the

reference for the DAC, and the THD is a measurement of the

harmonics present on the DAC output. It is measured in dB.

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