
22
CHAPTER 1 OVERVIEW
1.8
Notes on Handling Devices
When handling devices, pay special attention to the following nine items:
Strict observation of maximum rated voltage (latchup prevention)
Stabilization of supply voltage
Power-on
Treatment of unused input pins
Treatment of A/D converter power pin
External clock
Power supply pin
Analog power-on sequence of A/D converter
Notes on using the "DIV A, Ri" or "DIVW A, RWi" instruction
s Notes on Handling Devices
r Be sure that the maximum rated voltage is not exceeded (latchup prevention).
Do not apply a voltage higher than Vcc or lower than Vss to the input and output terminals of the
MB90560 or 565 series. Do not apply a voltage higher than the rating between Vcc and Vss. If
a voltage higher than the rating is applied, a latchup may occur. A latchup may result in thermal
damage to an element.
When turning the power to analog circuits, on or off be sure that the analog supply voltages
(AVcc, AVRH, and AVcc) and analog input voltage do not exceed the digital supply voltage
(Vcc).
r Stabilize the supply voltages.
Even within the operation guarantee range of the Vcc supply voltage, a malfunction can be
caused if the supply voltage undergoes a rapid change. For voltage stabilization guidelines, the
Vcc ripple fluctuations (P-P value) at commercial frequencies (50 to 60 Hz) should be
suppressed to "10%" or less of the reference Vcc value. During a momentary change such as
when switching a supply voltage, voltage fluctuations should also be suppressed so that the
"transient fluctuation rate" is 0.1 V/ms or less.
r Power-on
To prevent a malfunction in the built-in voltage drop circuit, secure "50
S (between 0.2 V and
2.7 V)" or more for the voltage rise time during power-on.
r Treatment of unused input pins
An unused input pin, if left open, may cause a malfunction or a permanent damage due to a
latchup. Every unused input pin must be pulled up or down using resistance of 2 k
or more.
An unused I/O pin must be opened by setting it to output mode or handled in the same way as
an input pin after it is set to input mode.