151
CHAPTER 13 A/D CONVERTER
(3) Sample & hold circuit
The sample & hold circuit samples each analog input sequentially applied from the input circuit, and sends it to
the voltage comparator. This circuit holds the sampled analog input voltage value during A/D conversion.
(4) Voltage comparator
The voltage comparator compares the analog input to the series resistor string output voltage.
(5) Series resistor string
The series resistor string is in AV
REF
to AV
SS
, and generates a voltage to be compared to the analog input.
(6) ANI0 to ANI4 pins
These are five analog input pins to input analog signals to undergo A/D conversion to the A/D converter. ANI0
to ANI4 are alternate-function pins that can also be used for digital input.
Caution
Use ANI0 to ANI4 input voltages within the specification range. If a voltage higher than
AV
REF
or lower than AV
SS
is applied (even if within the absolute maximum rating range), the
conversion value of that channel will be undefined and the conversion values of other
channels may also be affected.
(7) AV
REF
pin (Shared with AV
DD
pin)
This pin inputs the A/D converter reference voltage.
This pin also functions as an analog power supply pin. Supply power to this pin when the A/D converter is used.
It converts signals input to ANI0 to ANI4 into digital signals according to the voltage applied between AV
REF
and
AV
SS
.
The current flowing in the series resistor string can be reduced by setting the voltage to be input to the AV
REF
pin to AV
SS
level in the standby mode.
(8) AV
SS
pin
This is the GND potential pin of the A/D converter. Always keep it at the same potential as the V
SS
pin even
when not using the A/D converter.
Summary of Contents for mPD780973 Series
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