305CHAPTER 15 A/D CONVERTER15.5 A/D Converter Cautions(1) Current consumption in standby modeThe A/D converter operates on the main system clock. Therefore, its operation stops in STOP mode or inHALT mode with the subsystem clock. As a current still flows in the AV REF0 pin at this time, this current mustbe cut in order to minimize the overall system power dissipation. In Figure 15-9, the power dissipation canbe reduced by outputting a low-level signal to the output port in standby mode. However, there is no precisionto the actual AV REF0 voltage, and therefore the conversion values themselves lack precision and can onlybe used for relative comparison.Figure 15-9. Example of Method of Reducing Current Consumption in Standby ModeSeries Resistor StringVDDAVREF0AVREF0AVSSOutput Port..μ PD78078, 78078Y= V DD
