MB95710M Series
MB95770M Series
Document Number: 002-09307 Rev. *D
Page 157 of 172
22.5.3 Definitions of A/D Converter Terms
• Resolution
It indicates the level of analog variation that can be distinguished by the A/D converter.
When the number of bits is 12, analog voltage can be divided into 2
12
= 4096.
• Linearity error (unit: LSB)
It indicates how much an actual conversion value deviates from the straight line connecting the zero transition point
(“000000000000”
←
→
“000000000001”) of a device to the full-scale transition point (“111111111111”
←
→
“111111111110”) of the same device.
• Differential linear error (unit: LSB)
It indicates how much the input voltage required to change the output code by 1 LSB deviates from an ideal value.
• Total error (unit: LSB)
It indicates the difference between an actual value and a theoretical value. The error can be caused by a zero tran-
sition error, a full-scale transition errors, a linearity error, a quantum error, or noise.
V
FST
Ideal I/O characteristics
0x001
0x002
0x003
0x004
0xFFD
0xFFE
0xFFF
Digital output
Digital output
2 LSB
V
0T
1 LSB
0.5 LSB
Total error
Analog input
Analog input
0x001
0x002
0x003
0x004
0xFFD
0xFFE
0xFFF
Actual conversion
characteristic
Ideal characteristic
Actual conversion
characteristic
N
V
NT
: A/D converter digital output value
: Voltage at which the digital output transits from 0x(N
−
1) to 0xN
{1 LSB
×
(N
−
1)
+
0.5 LSB}
V
NT
Total error of digital output N
V
NT
−
{1 LSB
×
(N
−
1)
+
0.5 LSB}
1 LSB
LSB
=
V
CC
−
V
SS
4096
V
1 LSB =
V
SS
V
CC
V
SS
V
CC
