HD6432160 RENESAS [Renesas Technology Corp], HD6432160 Datasheet - Page 613

• Manufacturer Part Number: HD6432160
• Description: Hitachi 16-Bit Single-Chip Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

21.7.3
If conditions shown below are not met, the reliability of this LSI may be adversely affected.
21.7.4
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 voltage
(AV
(AV
21.7.5
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 voltage (AV
connected between AVcc and AVss as shown in figure 21.8. Also, the bypass capacitors
connected to AVcc and AV
connected to AV
If a filter capacitor is connected, 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 frequently, as in
scan mode, if the current charged and discharged by the capacitance of the sample-and-hold circuit
in the A/D converter exceeds the current input via the input impedance (R
the analog input pin voltage. Careful consideration is therefore required when deciding the circuit
constants.
Analog input voltage range
The voltage applied to analog input pin ANn during A/D conversion should be in the range
AVss
Digital input voltage range
The voltage applied to digital input pin CINn should be in the range AVss CINn
and Vss
Relation between AVcc, AVss and Vcc, Vss
For the relationship between AVcc, AVss and Vcc, Vss, set AVss = Vss. If the A/D converter
is not used, the AVcc and AVss pins must on no account be left open.
AVref pin reference voltage specification range
The reference voltage of the AVref pin should be in the range AVref
ref
SS
), and analog power supply (AV
) should be connected at one point to a stable digital ground (V
Notes on Board Design
Notes on Noise Countermeasures
Setting Range of Analog Power Supply and Other Pins
ANn
CINn
SS
.
AVref (n = 0 to 7).
Vcc (n = 0 to 15).
ref
, and the filter capacitor connected to AN2 to AN7, must be
CC
) by the analog ground (AV
Rev. 2.0, 08/02, page 573 of 788
SS
). Also, the analog ground
SS
) on the board.
in
AVcc.
), an error will arise in
ref
) should be
AVref