Cautions - Panasonic MN101L Series User Manual

16.3.3

Cautions

As A/D conversion could be easily damaged by noise, sufficient anti-noise measures are needed.
Anti-noise measures
Connect capacitors to analog input pins AN7 to AN0, which is positioned close to VSS pins.
In addition, Connect capacitors (the different capacities more than two are recommended.) to ADC reference volt-
age pins VREFP, which is positioned close to VSS pins.
During the A/D conversion, if the output level of LSI is changed, or the additional peripheral
circuits are switched to ON/OFF, the ADC may operate incorrectly, as the analog control ter-
minals cannot be fixed.
..
At circuit board evaluation, confirm the waveform of analog input pins.
..
VDD30 VSS
VREFP
AN0
to
AN7
Set near the VSS pin
Figure:16.3.3 ADC Recommended Example 1
VDD30 VSS
VREFP
AN0
to
AN7
Set near the VSS pin
Figure:16.3.4 ADC Recommended Example 2
Digital V
DD
Analog V
DD
Power
Supply
V
SS
V
DD
Power
Supply
V
SS
Chapter 16
A/D Converter (ADC)
Operation XVI - 13