AD5721 datasheet(20/31 Pages) AD

20 / 31 page

AD5761/AD5721

Data Sheet

Rev. C | Page 20 of 31

TERMINOLOGY

Total Unadjusted Error (TUE)

Total unadjusted error is a measure of the output error taking

all the various errors into account, namely INL error, offset

error, gain error, and output drift over supplies, temperature,

and time. TUE is expressed in % FSR.

Relative Accuracy or Integral Nonlinearity (INL)

For the DAC, relative accuracy, or integral nonlinearity, is a

measure of the maximum deviation, in LSB, from a straight line

passing through the endpoints of the DAC transfer function. A

typical INL error vs. DAC code plot is shown in Figure 7.

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. A

typical DNL error vs. code plot is shown in Figure 11.

Monotonicity

A DAC is monotonic if the output either increases or remains

constant for increasing digital input code. The AD5761/AD5721

are monotonic over their full operating temperature range.

Bipolar Zero Error

Bipolar zero error is the deviation of the analog output from the

ideal half-scale output of 0 V when the DAC register is loaded

with 0x8000 (straight binary coding) or 0x0000 (twos complement

coding) for the AD5761/AD5721.

Bipolar Zero Temperature Coefficient (TC)

Bipolar zero TC is a measure of the change in the bipolar zero

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

Zero-Scale Error

Zero-scale error is the error in the DAC output voltage when

0x0000 (straight binary coding) or 0x8000 (twos complement

coding) is loaded to the DAC register. Ideally, the output voltage

is negative full scale. A plot of zero-scale error vs. temperature is

shown in Figure 21.

Zero-Scale Error Temperature Coefficient (TC)

Zero-scale error TC is a measure of the change in zero-scale

error with a change in temperature. It is expressed in µV/°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 Temperature Coefficient (TC)

Offset error TC is a measurement of the change in offset error

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

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 in % FSR. A plot of gain error vs. temperature is

shown in Figure 24.

Gain Error Temperature Coefficient (TC)

Gain error TC is a measure of the change in gain error with

changes in temperature. It is expressed in ppm FSR/°C.

DC Power Supply Rejection Ratio (DC PSRR)

DC power supply rejection ratio is a measure of the rejection of

the output voltage to dc changes in the power supplies applied

to the DAC. It is measured for a given dc change in power supply

voltage and is expressed in mV/V.

AC Power Supply Rejection Ratio (AC PSRR)

AC power supply rejection ratio is a measure of the rejection of

the output voltage to ac changes in the power supplies applied

to the DAC. It is measured for a given amplitude and frequency

change in power supply voltage and is expressed in decibels.

Output Voltage Settling Time

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

the output to settle to a specified level for a full-scale input

change. Full-scale settling time is shown in Figure 39 to Figure 42.

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 (see Figure 47 and Figure 48).

Glitch Impulse Peak Amplitude

Glitch impulse peak amplitude is the peak amplitude of the

impulse injected into the analog output when the input code in

the DAC register changes state. It is specified as the amplitude

of the glitch in mV and is measured when the digital input code

is changed by 1 LSB at the major carry transition.

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 is

measured when the DAC output is not updated. It is specified in

nV-sec and measured with a full-scale code change on the data bus.

Noise Spectral Density

Noise spectral density is a measurement of the internally generated

random noise characterized as a spectral density (nV/√Hz). It is

measured by loading the DAC to full scale and measuring noise

at the output. It is measured in nV/√Hz. A plot of noise spectral

density is shown in Figure 60.

Total Harmonic Distortion (THD)

THD is the ratio of the rms sum of harmonics to the fundamental.

For the AD5761/AD5721, it is defined as

log

)

(

THD

where:

V1 is the rms amplitude of the fundamental.

V2, V3, V4, V5, and V6 are the rms amplitudes of the second

through the sixth harmonics.

AD5721 データシート(PDF) 20 Page - Analog Devices

AD5721 データシート(HTML) 20 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

データシートダウンロード