R01UH0823EJ0100 Rev.1.00
Page 1618 of 1823
Jul 31, 2019
RX23W Group
44. 12-Bit A/D Converter (S12ADE)
44.8.11
Voltage Range of Analog Power Supply Pins
If this MCU is used with the voltages outside the following ranges, the reliability of the MCU may be affected.
Analog input voltage range
Voltage applied to analog input pins ANn: AVSS0 ≤ VAN ≤ AVCC0
Reference voltage range applied to pins VREFH0 and VREFL0: VREFH0 ≤ AVCC0, VREFL0 = AVSS0
Conversion will not succeed if the voltage applied to analog input pins ANn is greater than VREFH0 (see
Figure 44.30
Relationship Between Voltage Applied to Analog Input Pins and Output Code
Relationship between power supply pin pairs (AVCC0–AVSS0, VREFH0–VREFL0, VCC–VSS)
The following condition should be satisfied: AVSS0 = VSS. When performing A/D conversion of analog input pin
ANn (n = 016 to 020, 027), the following condition should be satisfied: AVCC0 = VCC. A 0.1-μF capacitor should
be connected between each pair of power supply pins to create a closed loop with the shortest route possible as
shown in
, and connection should be made so that the following conditions are satisfied at the supply
side.
VREFL0 = AVSS0 = VSS
When the 12-bit A/D converter is not used, the following conditions should be satisfied.
VREFH0 = AVCC0 = VCC and VREFL0 = AVSS0 = VSS
Figure 44.31
Power Supply Pin Connection Example
A/D converter output code
FFFh (logical value)
VREFL0 = AVSS0
VREFH0
AVCC0
VAN
VCC
AVCC0
AVSS0
VREFH0
VSS
0.1 µF
VREFL0
0.1 µF
0.1 µF