CHAPTER 12 A/D CONVERTER
Preliminary User’s Manual U16315EJ1V0UD
240
(8) Conversion time
This expresses the time since sampling has been started until digital output is obtained.
The sampling time is included in the conversion time in the characteristics table.
(9) Sampling time
This is the time the analog switch is turned on for the analog voltage to be sampled by the sample & hold circuit.
Sampling
time
Conversion time
12.6 Cautions for A/D Converter
(1) Power consumption in standby mode
The A/D converter stops operating in the standby mode. At this time, the power consumption can be reduced by
stopping the conversion operation (by setting bit 7 (ADCS) of the A/D converter mode register (ADM) to 0).
Figure 12-19 shows the circuit configuration of series resistor string.
Figure 12-19. Circuit Configuration of Series Resistor String
AV
REF
AV
SS
P-ch
Series resistor string
ADCS
(2) Input range of ANI0 to ANI7
Observe the rated range of the ANI0 to ANI7 input voltage. If a voltage of AV
REF
or higher and AV
SS
or lower
(even in the range of absolute maximum ratings) is input to an analog input channel, the converted value of that
channel becomes undefined. In addition, the converted values of the other channels may also be affected.