HD64F2357F20V Datasheet, PDF (584/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

However, if a large capacitance is provided externally, the input load will essentially comprise only the internal input
resistance of 10 kohm, and the signal source impedance is ignored.
However, since a low-pass filter effect is obtained in this case, it may not be possible to follow an analog signal with a
large differential coefficient (e.g., 5 mV/µs or greater).
When converting a high-speed analog signal, a low-impedance buffer should be inserted.
Influences on Absolute Precision: Adding capacitance results in coupling with GND, and therefore noise in GND may
adversely affect absolute precision. Be sure to make the connection to an electrically stable GND such as AV_SS.
Care is also required to insure that filter circuits do not communicate with digital signals on the mounting board, so acting
as antennas.
Sensor output
impedance
to 10 k Ω
Sensor input
Low-pass
filter C
to 0.1 µF
H8/2357
Group
C_in =
15 pF
A/D converter
equivalent circuit
10 kΩ
20 pF
Note: Values are reference values.
Figure 16-10 Example of Analog Input Circuit
Rev.6.00 Oct.28.2004 page 554 of 1016
REJ09B0138-0600H