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ADT7517
(Rev.:RevA)

SPI/I2C Compatible, Temperature Sensor, 4-Channel ADC and Quad Voltage Output DAC

Analog Devices 

ADT7516/ADT7517/ADT7519

TERMINOLOGY

Relative Accuracy

Relative accuracy or integral nonlinearity (INL) is a measure of

the maximum deviation, in LSBs, from a straight line passing

through the endpoints of the transfer function. Typical INL

versus code plots can be seen in Figure 10, Figure 11, and

Figure 12.

Differential Nonlinearity

Differential nonlinearity (DNL) is the difference between the

measured change and the ideal 1 LSB change between any two

adjacent codes. A specified differential nonlinearity of ±0.9 LSB

maximum ensures monotonicity. Typical DAC DNL versus code

plots can be seen in Figure 13, Figure 14, and Figure 15.

Total Unadjusted Error (TUE)

Total unadjusted error is a comprehensive specification that

includes the sum of the relative accuracy error, gain error, and

offset error under a specified set of conditions.

Offset Error

This is a measure of the offset error of the DAC and the output

amplifier (See Figure 8 and Figure 9). It can be negative or

positive, and it is expressed in mV.

Offset Error Match

This is the difference in offset error between any two channels.

Gain Error

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

deviation in slope of the actual DAC transfer characteristic

from the ideal expressed as a percentage of the full-scale range.

Gain Error Match

This is the difference in gain error between any two channels.

Offset Error Drift

This is a measure of the change in offset error with changes in

temperature. It is expressed in (ppm of full-scale range)/°C.

Gain Error Drift

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

temperature. It is expressed in (ppm of full-scale range)/°C.

Long Term Temperature Drift

This is a measure of the change in temperature error with the

passage of time. It is expressed in °C. The concept of long-term

stability has been used for many years to describe the amount

an IC’s parameter would shift during its lifetime. This is a

concept that has typically been applied to both voltage

references and monolithic temperature sensors. Unfortunately,

integrated circuits cannot be evaluated at room temperature

(25°C) for 10 years or so to determine this shift. Manufacturers

perform accelerated lifetime testing of integrated circuits by

operating ICs at elevated temperatures (between 125°C and

150°C) over a shorter period (typically between 500 and 1000

hours). As a result, the lifetime of an integrated circuit is

significantly accelerated due to the increase in rates of reaction

within the semiconductor material.

DC Power Supply Rejection Ratio (PSRR)

This 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 dB. VREF is held at 2 V and VDD is varied ±10%.

DC Crosstalk

This is the dc change in the output level of one DAC in response

to a change in the output of another DAC. It is measured with a

full-scale output change on one DAC while monitoring another

DAC. It is expressed in µV.

Reference Feedthrough

This 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 (i.e., LDAC is high). It is expressed in dB.

Channel-to-Channel Isolation

This is the ratio of the amplitude of the signal at the output of

one DAC to a sine wave on the reference input of another DAC.

It is measured in dB.

Major-Code Transition Glitch Energy

Major-code transition glitch energy is the energy of the impulse

injected into the analog output when the code in the DAC

register changes state. It is normally specified as the area of the

glitch in nV-s and is measured when the digital code is changed

by 1 LSB at the major carry transition (011 . . . 11 to 100 . . . 00 or

100 . . . 00 to 011 . . . 11).

Digital Feedthrough

Digital feedthrough is a measure of the impulse injected into

the analog output of a DAC from the digital input pins of the

device but is measured when the DAC is not being written to. It

is specified in nV-s and is measured with a full-scale change on

the digital input pins, i.e., from all 0s to all 1s or vice versa.

Digital Crosstalk

This is the glitch impulse transferred to the output of one DAC

at midscale in response to a full-scale code change (all 0s to all

1s and vice versa) in the input register of another DAC. It is

measured in standalone mode and is expressed in nV-s.

Analog Crosstalk

This is the glitch impulse transferred to the output of one DAC

due to a change in the output of another DAC. It is measured by

loading one of the input registers with a full-scale code change

(all 0s to all 1s and vice versa) while keeping LDAC high. Then

pulse LDAC low and monitor the output of the DAC whose

digital code was not changed. The area of the glitch is expressed

in nV-s.

Rev. A | Page 11 of 44

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