ADT7518 
 
Rev. A | Page 10 of 40 
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 ?.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)/癈.  
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)/癈. 
Long Term Temperature Drift 
This is a measure of the change in temperature error over time. 
It is expressed in 癈. The concept of long-term stability has been 
used for many years to describe the amount an ICs parameter 
shifts during its lifetime. This is a concept that has typically 
been applied to both voltage references and monolithic temp-
erature sensors. Unfortunately, integrated circuits cannot be 
evaluated at room temperature (25癈) for 10 years or so to 
determine this shift. Manufacturers perform accelerated lifetime 
testing of integrated circuits by operating ICs at elevated temp-
eratures (between 125癈 and 150癈) over a shorter period 
(typically between 500 and 1,000 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 V
OUT
 to 
a change in V
DD
 for full-scale output of the DAC. It is measured 
in dB. V
REF
 is held at 2 V and V
DD
 is varied ?0%. 
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 礦. 
Reference Feedthrough 
This is the ratio of the amplitude of the signal at the DAC out-
put 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...1 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.