Figure 18.7 Example Of Analog Input Protection Circuit; Table 18.6 Analog Pin Specifications - Renesas H8S/2437 Hardware Manual

If a filter capacitor is connected, the input currents at the analog input pins (AN0 to AN15) 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
the analog input pin voltage. Careful consideration is therefore required when deciding the circuit
constants.
1 1
* *
Notes: Values are reference values.
1.
10 µF
2. R : Input impedance
in

Figure 18.7 Example of Analog Input Protection Circuit

Table 18.6 Analog Pin Specifications

Item
Analog input capacitance
Permissible signal source impedance
Rev. 1.00, 09/03, page 522 of 704
2
R 100
*
in
0.1 µF
0.01 µF
Min.
—
—
), an error will arise in
in
AV
CC
Vref
AN0 to AN15
AV
SS
Max.
20
5
Unit
pF
kΩ