HD6417706 Datasheet, PDF (557/709 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series

19.9 Usage Note
When using the A/D converter, note the points listed in section 19.7.1 below.
19.9.1 Setting Analog Input Voltage
• Analog Input Voltage Range: During A/D conversion, the voltages input to the analog input
pins ANn should be in the range AV_SS ≤ ANn ≤ AV_CC (n = 0 to 3).
• AV_CC, AV_SS, Input Voltage: AV_CC and AV_SS should be related as follows: AV_CC = V_CCQ ±
0.2 V and AV_SS = V_SS.
19.9.2 Processing of Analog Input Pins
To prevent damage from voltage surges at the analog input pins (AN0 to AN3), connect an input
protection circuit like the one shown in figure 19.11. The circuit shown also includes an RC filter
to suppress noise. This circuit is shown as an example; The circuit constants should be selected
according to actual application conditions. Table 19.4 lists the analog input pin specifications and
figure 19.12 shows an equivalent circuit diagram of the analog input ports.
AV_CC
100 Ω
SuperH microprocessor
AN0 to AN3
*
0.1 µF
AV_SS
Note: _*
10 µF
0.01 µF
Figure 19.11 Example of Analog Input Protection Circuit
AN0 to AN3
1.0 kΩ
20 pF
1 MΩ
Figure 19.12 Analog Input Pin Equivalent Circuit
Rev. 4.00, 03/04, page 511 of 660