MB89930A Series
5. A/D Converter
(1) A/D Converter Electrical Characteristics
(VCC = 5.0 V ± 10%, AVSS = VSS = 0.0 V, Ta = −40 °C to +85 °C)
Parameter
Symbol
Min
Value
Typ
Unit Remarks
Max
Resolution
10
bit
Total error
Linearity error
−5.0
+5.0
LSB
−3.0
+3.0
LSB
Differential linearity error
−2.5
+2.5
LSB
Zero transition voltage
VOT AVSS − 3.5 LSB AVSS + 0.5 LSB AVSS + 4.5 LSB V
Full-scale transition voltage
VFST VCC − 6.5 LSB VCC − 1.5 LSB VCC + 2.0 LSB V
A/D mode conversion time
38 tINST*
µs
Analog port input current
IAIN
10
µA
Analog input voltage range
0
VCC
V
* : For information on tinst, see “ (4) Instruction Cycle” in “4. AC Characteristics.”
(2) A/D Converter Glossary
• Resolution
Analog changes that are identifiable with the A/D converter
When the number of bits is 10, analog voltage can be divided into 210 = 1024.
• Linearity error (unit : LSB)
The deviation of the straight line connecting the zero transition point (“00 0000 0000” ↔ “00 0000 0001”) with
the full-scale transition point (“11 1111 1111” ↔ “11 1111 1110”) from actual conversion characteristics
• Differential linearity error (unit : LSB)
The deviation of input voltage needed to change the output code by 1 LSB from the theoretical value
• Total error (unit : LSB)
The difference between theoretical and actual conversion values
Theoretical I/O characteristics
Total error
3FF
VFST
3FF
3FE
3FE
Actual conversion
3FD
1.5 LSB
3FD
value
{1 LSB × N + 0.5 LSB}
004
003
VOT
002
1 LSB
001
AVSS
0.5 LSB
Analog input
1 LSB =
VFST − VOT
1022
(V)
004
003
VNT
Actual conversion
002
value
001
Theoretical value
VCC
AVSS
VCC
Analog input
Total error of digital output N = VNT − {1 LSB × N + 0.5 LSB}
1 LSB
32