SH7040 Datasheet, PDF (622/923 Pages) Renesas Technology Corp – Renesas 32-Bit Single-Chip RISC Microprocessor SuperH RISC engine Family/SH7040 Series(CPU Core SH-2)

16.7 Usage Notes
The following points should be noted when using the mid-speed A/D converter.
16.7.1 Analog Voltage Settings
(1) Analog input voltage range
The voltage applied to analog input pins during A/D conversion should be in the range AVSS
≤ ANn ≤ AV_ref (n = 0 to 7).
(2) AV_CC and AV_SS input voltages
For the AV_CC and AV_SS input voltages, set AV_CC = V_CC ±10% and AV_SS = V_SS. When the
medium-speed A/D converter is not used, set AV_CC = V_CC and AV_SS = V_SS.
(3) AVref input voltage
For the AV_ref pin input voltage analog reference, set AV_ref ≤ AV_CC. When the medium-speed
A/D converter is not used, set AV_ref = AV_CC.
(4) AV_CC and AV_ref must be connected to the power supply (V_CC) even if the medium-speed A/D
converter is not used or is in standby mode.
16.7.2 Handling of Analog Input Pins
To prevent damage from surges and other abnormal voltages at the analog input pins (AN0-AN7),
connect a protection circuit such as that shown in figure 16.8. 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 16.9 shows an equivalent circuit for the analog input pins, and table 16.6 summarizes the
analog input pin specifications.
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