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MB89960 Series
14
I
HANDLING DEVICES
1.
Do not exceed maximum rated voltage (to prevent latch-up)
Latch-up may occur on CMOS ICs if voltage higher than V
CC
or lower than V
SS
is applied to input or output pins
other than medium- and high voltage pins or if the voltage applied between V
CC
and V
SS
higher the rating.
If latch-up occurs, the power supply current increases rapidly resulting in thermal damage to circuit elements.
Therefore, ensure that maximum ratings are not exceeded in circuit operation.
Similarly, when turning the analog power supply on or off, ensure the analog power supply voltages (AV
CC
and
AVR) and analog input voltages do not exceed the digital power supply (V
CC
) .
2.
Power supply voltage fluctuations
Rapid fluctuation of the voltage may cause the device to misoperate, even if the voltage remains within the
allowed operating range.
The standard for power supply voltage stability is a peak-to-peak V
CC
ripple voltage at the mains supply frequency
(50 to 60 Hz) of 10
%
or less of V
CC
and a transient voltage change rate of 0.1 V/ms or less such as when turning
the power supply on or off.
3.
Treatment of unused input pins
Leaving unused input pins unconnected can cause misoperation or permanent damage to the device due to
latchup. Always pull-up or pull-down unused input pins using a 2 k
or larger resistor.
If some I/O pins are unused, either set as outputs and leave open circuit or set as inputs and treat in the same
way as input pins.
4.
Treatment of N.C. pins
Always leave N.C. (internally connected) pins open.
5.
Treatment of power supply pins on microcontrollers with an A/D converter
Even if not using the A/D converter, connect to be AV
CC
=
V
CC
and AV
SS
=
AVR
=
V
SS
.
6.
Precautions on using an external clock
An oscillation stabilization delay occurs after a power-on reset or when recovering from sub-clock or stop mode,
even if an external clock is used.