HD64F3039F18 Datasheet, PDF (455/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 13 A/D Converter
If a filter capacitor is connected as shown in figure 13.7, the input currents at the analog input pins
(AN₀ to AN₇) are averaged, and so an error may arise. Also, when A/D conversion is performed
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. Therefore careful consideration is required
when deciding the circuit constants.
AV_CC
R_in^*2
100 Ω
*1
0.1 µF
Notes: Values are reference values.
1.
10 µF
0.01 µF
AN0 to AN7
AV_SS
2. R_in: Input impedance
Figure 13.7 Example of Analog Input Protection Circuit
Table 13.5 Analog Pin Specifications
Item
Min
Max
Unit
Analog input capacitance
—
20
pF
Permissible signal source impedance
—
10*
kΩ
Note: * When V_CC = 4.0 V to 5.5 V and φ ≤ 12 MHz
Rev.3.00 Mar. 26, 2007 Page 431 of 682
REJ09B0353-0300