SH7011 Datasheet, PDF (256/292 Pages) Renesas Technology Corp – CMOS single-chip microprocessors

13.6 Notes on Use
The following points should be noted when using the A/D converter.
13.6.1 Analog Voltage Settings
Analog Input Voltage Range: The voltage applied to analog input pins during A/D conversion
should be in the range AV_SS ANn AV _CC (n = 0 to 6).
AV_CC and AV_SS input voltages: For the AV_CC and AV_SS input voltages, set AV_CC = 3.3 V ± 10%,
and AV_SS = V_SS. When the A/D converter is not used, set AV_CC = V_CC and AV_SS = V_SS.
13.6.2 Handling of Analog Input Pins
To prevent damage from surges and other abnormal voltages at the analog input pins (AN0–AN6),
connect a protection circuit such as that shown in figure 13.8. This circuit also includes a CR filter
function that suppresses error due to noise. The circuit shown here is only a design example;
circuit constants must be decided on the basis of the actual operating conditions.
Figure 13.9 shows an equivalent circuit for the analog input pins, and table 13.5 summarizes the
analog input pin specifications.
AVcc
100 Ω
AN0–AN6
SH7011
*
0.1 µF
AVss
Note:
10 µF
0.01 µF
Figure 13.8 Example of Analog Input Pin Protection Circuit
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