HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 748

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 16 A/D Converter (8 Analog Input Channel Version)
16.6
The following points should be noted when using the A/D converter.
Setting Range of Analog Power Supply and Other Pins
1. Analog input voltage range
2. Relation between AV
3. V
If conditions 1, 2, and 3 above are not met, the reliability of the device may be adversely affected.
Notes on Board Design: In board design, digital circuitry and analog circuitry should be as
mutually isolated as possible, and layout in which digital circuit signal lines and analog circuit
signal lines cross or are in close proximity should be avoided as far as possible. Failure to do so
may result in incorrect operation of the analog circuitry due to inductance, adversely affecting A/D
conversion values.
Also, digital circuitry must be isolated from the analog input signals (AN0 to AN7), analog
reference power supply (V
Also, the analog ground (AV
on the board.
Notes on Noise Countermeasures: A protection circuit connected to prevent damage due to an
abnormal voltage such as an excessive surge at the analog input pins (AN0 to AN7) and analog
reference power supply (V
16.7.
Also, the bypass capacitors connected to AV
to AN7 must be connected to AV
If a filter capacitor is connected as shown in figure 16.7, the input currents at the analog input pins
(AN0 to AN7) are averaged, and so an error may arise. Also, when A/D conversion is performed
Rev.6.00 Sep. 27, 2007 Page 718 of 1268
REJ09B0220-0600
The voltage applied to analog input pins ANn during A/D conversion should be in the range
AV
As the relationship between AV
not used, the AV
The analog reference voltage input at the V
V
pin open.
ref
ref
SS
input range
pin should be set as V
≤ ANn ≤ V
Usage Notes
CC
ref
.
and AV
CC
ref
ref
, AV
), and analog power supply (AV
) should be connected between AV
SS
ref
) should be connected at one point to a stable digital ground (V
SS
= V
SS
SS
pins must not be left open.
and V
.
CC
CC
, AV
when the A/D converter is not used. Do not leave the V
CC
SS
, V
CC
and V
SS
ref
and V
pin should be set in the range V
CC
, V
ref
and the filter capacitor connected to AN0
SS
, set AV
CC
) by the analog ground (AV
CC
and AV
SS
= V
SS
SS
. If the A/D converter is
as shown in figure
ref
≤ AV
CC
SS
. The
).
SS
ref
)