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CHAPTER 12 A/D CONVERTER
User
’
s Manual U14701EJ3V0UD
(4) Zero scale error
This shows the difference between the actual measured value of the analog input voltage and the theoretical
value (1/2 LSB) when the digital output changes from 0
……
000 to 0
……
001. If the actual measured value is
greater than the theoretical value, it shows the difference between the actual measured value of the analog input
voltage and the theoretical value (3/2LSB) when the digital output changes from 0
……
001 to 0
……
010.
(5) Full scale error
This shows the difference between the actual measured value of the analog input voltage and the theoretical
value (full scale
–
3/2 LSB) when the digital output changes from 1
……
110 to 1
……
111.
(6) Integral linearity error
This shows the degree to which the conversion characteristics deviate from the ideal linear relationship. It
expresses the maximum value of the difference between the actual measured value and the ideal straight line
when the zero scale error and full scale error are 0.
(7) Differential linearity error
The ideal width to output a certain code is 1LSB. The following shows the difference between the actual
measurement values and ideal values of the width when outputting a certain code.
Figure 12-11. Zero Scale Error
Figure 12-12. Full Scale Error
Figure 12-13. Integral Linearity Error
Figure 12-14. Differential Linearity Error
111
011
010
001
Zero scale error
Ideal line
000
0
1
2
3
AV
REF0
D
Analog input (LSB)
111
110
101
000
0
AV
REF0
AV
REF0
–
1
AV
REF0
–
2
AV
REF0
–
3
Analog input (LSB)
D
Ideal line
Full scale error
0
AV
REF0
D
Analog input
Integral
linearity
error
Ideal line
1
……
1
0
……
0
0
AV
REF0
D
1......1
0......0
Ideal width of 1LSB
Differential
linearity error
Analog input