SH7709S Datasheet, PDF (676/807 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer Super RISC engine Family/SH7700 Series

Digital output
Digital output
(2) Full-scale error
Ideal A/D
conversion
111
characteristic
110
101
100
011
010
(3) Quantization
error
001
000
0 1/8 2/8 3/8 4/8 5/8 6/8 7/8 FS
Analog input
FS: Full-scale voltage
voltage
Ideal A/D
conversion
characteristic
(4) Nonlinearity
error
Actual A/D
convertion
characteristic
(1) Offset error
FS
Analog input
voltage
Figure 20.8 Definitions of A/D Conversion Accuracy
20.7 Usage Notes
When using the A/D converter, note the following points.
20.7.1 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 7).
• Relationships of AV_CC and AV_SS: AV_CC and AV_SS should be related as follows: AV_CC =
V_CC ± 0.3 V and AV_SS = V_SS.
20.7.2 Processing of Analog Input Pins
To prevent damage from voltage surges at the analog input pins (AN0 to AN7), connect an input
protection circuit like the one shown in figure 20.9. The circuit shown also includes an CR filter to
suppress noise. This circuit is shown as an example; the circuit constants should be selected
according to actual application conditions. Table 20.5 lists the analog input pin specifications and
figure 20.10 shows an equivalent circuit diagram of the analog input ports.
Rev. 5.00, 09/03, page 632 of 760