AD5693 datasheet(18/26 Pages) AD

18 / 26 page

AD5693R/AD5692R/AD5691R/AD5693

Data Sheet

Rev. D | Page 18 of 26

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. For typical INL vs. code plots, see Figure 9, Figure 10,

and Figure 11.

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. For

typical DNL vs. code plots, see Figure 12, Figure 13, and Figure 14.

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 V. The zero code error is always positive in the AD5693R/

AD5692R/AD5691R/AD5693 because the output of the DAC

cannot go 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. For plots of zero code error, see in Figure 22 and Figure 25.

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 is VREF − 1 LSB or |2 × VREF| − 1 LSB. Full-scale error is

expressed in percent of full-scale range. For plots of full-scale error

vs. temperature, see Figure 21 and Figure 24.

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 AD5693R with

Code 512 loaded in the DAC register (Code 256 for the AD5692R

and Code 128 for the AD5693R/AD5693). 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 full-scale output of the DAC. It is measured

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

Output Voltage Settling Time

This is the amount of time it takes for the output of a DAC to

settle to a specified level for a ¼ to ¾ full-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)

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, that is, from all 0s to all 1s and vice versa.

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. For plots of noise spectral density, see Figure 29,

Figure 32, and Figure 33. The noise spectral density for the

reference is shown in Figure 28 and Figure 31.

Multiplying Bandwidth

The amplifiers within the DAC have a finite bandwidth. The

multiplying bandwidth is a measure of these finite bandwidths. 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 its attenuated

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

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

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

Voltage Reference Temperature Coefficient (TC)

Voltage reference TC is a measure of the change in the reference

output voltage with a change in temperature. The reference TC

is calculated using the box method, which defines the TC as the

maximum change in the reference output over a given tempera-

ture range expressed in ppm/°C as follows:













−

TempRange

REFnom

REFmin

REFmax

where:

VREFmax is the maximum reference output measured over the

total temperature range.

VREFmin is the minimum reference output measured over the total

temperature range.

VREFnom is the nominal reference output voltage, 2.5 V.

TempRange is the specified temperature range, −40°C to +105°C.

AD5693 Datasheet(PDF) 18 Page - Analog Devices

AD5693 Datasheet(HTML) 18 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

Datasheet Download

Link URL