SN8P2740 Series
ADC, OP-amp, Comparator 8-Bit Micro-Controller
13.6 ADC APPLICATION CIRCUIT
C
B
A
External High
Reference Voltage
AVREFH
47uF
0.1uF
0.1uF
MCU
Analog Signal Input
AINn/P4.n
VSS
VCC
Main Power Trunk
GND
The analog signal is inputted to ADC input pin “AINn/P4.n”. The ADC input signal must be through a 0.1uF capacitor
“A”. The 0.1uF capacitor is set between ADC input pin and VSS pin, and must be on the side of the ADC input pin as
possible. Don‟t connect the capacitor‟s ground pin to ground plain directly, and must be through VSS pin. The capacitor
can reduce the power noise effective coupled with the analog signal.
If the ADC high reference voltage is from external voltage source, the external high reference is connected to AVREFH
pin (P4.0). The external high reference source must be through a 47uF ”C” capacitor first, and then 0.1uF capacitor “B”.
These capacitors are set between AVREFH pin and VSS pin, and must be on the side of the AVREFH pin as possible.
Don‟t connect the capacitor‟s ground pin to ground plain directly, and must be through VSS pin.
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