HD64F2638F20J Datasheet, PDF (750/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 17 A/D Converter
H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
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.
*1
*1
R_in* ²
100Ω
0.1 μF
Notes: Values are reference values.
1.
10 μF
0.01 μF
AVCC
Vref
AN0 to AN11
AVSS
2. R_in: Input impedance
Figure 17-7 Example of Analog Input Protection Circuit
Table 17-7 Analog Pin Specifications
Item
Min
Analog input capacitance
—
Permissible signal source impedance
—
Max
Unit
20
pF
5
kΩ
Page 700 of 1458
REJ09B0103-0800 Rev. 8.00
May 28, 2010