h8s-2111b Renesas Electronics Corporation., h8s-2111b Datasheet - Page 460

• Manufacturer Part Number: h8s-2111b
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

16.7.3
If conditions shown below are not met, the reliability of this LSI may be adversely affected.
• Analog input voltage range
• Relation between AVcc, AVss and Vcc, Vss
• AVref pin reference voltage specification range
16.7.4
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 AN5), analog reference voltage
(AV
(AV
16.7.5
A protection circuit connected to prevent damage due to an abnormal voltage such as an excessive
surge at the analog input pins (AN0 to AN5) and analog reference voltage (AV
connected between AVcc and AVss as shown in figure 16.8. 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 AN5) 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.
Rev. 1.00, 05/04, page 426 of 544
The voltage applied to analog input pin ANn during A/D conversion should be in the range
AVss ≤ ANn ≤ AVref (n = 0 to 5).
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.
The reference voltage of the AVref pin should be in the range AVref ≤ AVcc.
ref
SS
), and analog power supply (AV
) should be connected at one point to a stable digital ground (V
Setting Range of Analog Power Supply and Other Pins
Notes on Board Design
Notes on Noise Countermeasures
SS
.
ref
, and the filter capacitor connected to AN0 to AN5, must be
CC
) by the analog ground (AV
SS
). Also, the analog ground
SS
) on the board.
in
), an error will arise in
ref
) should be