Datasheet

Section 16 A/D Converter (8 Analog Input Channel Version)
Rev.6.00 Sep. 27, 2007 Page 719 of 1268
REJ09B0220-0600
frequently, as in scan mode, if the current charged and discharged by the capacitance of the
sample-and-hold circuit in the A/D converter exceeds the current input via the input impedance
(R
in
), an error will arise in the analog input pin voltage. Careful consideration is therefore required
when deciding the circuit constants.
AV
CC
*
1
*
1
V
ref
AN0 to AN7
AV
SS
Notes: Values are reference values.
1.
2. R
in
: Input impedance
R
in
*
2
100 Ω
0.1 μF
0.01 μF10 μF
Figure 16.7 Example of Analog Input Protection Circuit
A/D Conversion Precision Definitions: The chip’s A/D conversion precision definitions are
given below.
• Resolution
The number of A/D converter digital output codes
• Offset error
The deviation of the analog input voltage value from the ideal A/D conversion characteristic
when the digital output changes from the minimum voltage value B'0000000000 to
B'0000000001. (See figure 16.9.)