MB88111 Datasheet, PDF (22/26 Pages) Fujitsu Component Limited. – A/D Converter (With 24-Channel Input at 10-bit Resolution)

MB88111
s DEFINITIONS OF A/D CONVERTER TERMS
• Resolution
Analog transition identifiable by the A/D converter
• Linearity error
Deviation of the straight line drawn between the zero transition point (00 0000 0000 ↔ 00 0000 0001) and
the full-scale transition point (11 1111 1110 ↔ 11 1111 1111) of the device from actual conversion charac-
teristics
• Differential linearity error
Deviation from the ideal input voltage required to shift output code by one LSB
• Total error
Difference between actual and logical values. This error is caused by a zero transition error, full-scale transition
error, linearity error, quantum error, and by noise.
Ideal I/O characteristics
3FF
3FE
3FD
1.5 LSB
004
VOT
(Ideal value)
003
VFST
(Ideal value)
002
1 LSB
(Ideal value)
001
0.5 LSB
AVRL
Analog input
AVRH–AVRL
1 LSB (Ideal value) =
[v]
1024
V OT (Ideal value) = 0.5 LSB
[v]
AVRH
V FST (Ideal value) = AVRH - 1.5 LSB ^[v]
3FF
3FE
3FD
Total error
Actual conversion
characteristics
{1 LSB×(N–1) +0.5 LSB}
004
VNT'
003
(Measured value)
Actual conversion
002
characteristics
Ideal characteristics
001
AVRL
Analog input
AVRH
Total error of
digital output N
=
VNT'– {1 LSB × (N–1) +0.5 LSB}
1 LSB
(Continued)
22