MB90610A Series
s
HANDLING DEVICES
1. Preventing Latchup
Latchup occurs in a CMOS IC if a voltage greater than V
CC
or less than V
SS
is applied to an input or output pin
or if the voltage applied between V
CC
and V
SS
exceeds the rating.
If latchup 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.
For the same reason, also ensure that the analog supply voltage does not exceed the digital supply voltage.
2. Treatment of Unused Pins
Leaving unused input pins unconnected can cause misoperation. Always pull-up or pull-down unused pins.
3. External Reset Input
To reliably reset the controller by inputting an “L” level to the RST pin, ensure that the “L” level is applied for at
least five machine cycles. Take particular note when using an external clock input.
4. V
CC
and V
SS
Pins
Ensure that all V
CC
pins are at the same voltage. The same applies for the V
SS
pins.
5. Cautions When Using an External Clock
Drive the X0 pin only when using an external clock.
• Using an External Clock
MB90610A Series
X0
OPEN
X1
6. A/D Converter Power Supply and the Turn-on Sequence for Analog Inputs
Always cut the A/D converter power supply (AV
CC
, AVRH, AVRL) and analog inputs (AN0 to AN7) before
disconnecting the digital power supply (V
CC
).
When turning the power on or off, ensure that AVRH does not exceed AV
CC
.
Also, when using the analog input pins as input ports, ensure that the input voltage does not exceed AV
CC
.
14
FUJITSU [ FUJITSU COMPONENT LIMITED. ]
