A/D Converter Cautions; Example Of Method Of Reducing Current Dissipation In Standby Mode - NEC PD78081(A) User Manual

10.5 A/D Converter Cautions

(1) Power consumption in standby mode
The A/D converter operates on the main system clock. Therefore, its operation stops in STOP mode. As a
current still flows in the AV
power dissipation. In Figure 10-9, the power dissipation can be reduced by outputting a low-level signal to
the output port in standby mode. However, there is no precision to the actual AV
the conversion values themselves lack precision and can only be used for relative comparison.
Figure 10-9. Example of Method of Reducing Current Dissipation in Standby Mode
(2) Input range of ANI0 to ANI7
The input voltages of ANI0 to ANI7 should be within the specification range. In particular, if a voltage above
AV or below AV
REF
channel will be indeterminate. The conversion values of the other channels may also be affected.
CHAPTER 10 A/D CONVERTER
pin at this time, this current must be cut in order to minimize the overall system
REF
Output Port
AV
REF
. .
AV = V
REF DD
AV
SS
is input (even if within the absolute maximum rating range), the conversion value for that
SS
V
DD
PD78082
Series Resistor String
voltage, and therefore
REF
131