15.6.6
Effect on Absolute Accuracy
Attaching an external capacitor creates a coupling with ground, so if there is noise on the ground
line, it may degrade absolute accuracy. The capacitor must be connected to an electrically stable
ground, such as AVSS.
If a filter circuit is used, be careful of interference with digital signals on the same board, and
make sure the circuit does not act as an antenna.
H8/3337 Series
or H8/3397
Series chip
Equivalent circuit of A/D
converter
Sensor output
impedance,
10 kΩ
up to 10 kΩ
Sensor input
Cin
15 pF
=
20 pF
Low-pass
filter C,
up to 0.1 µF
Note: Figures are reference values.
Figure 15.10 Example of Analog Input Circuit
352
RENESAS [ RENESAS TECHNOLOGY CORP ]
