MB90820B Series
14
DS07-13751-2E
■ HANDLING DEVICES
Special care is required for the following when handling the device :
Preventing latch-up
Stabilization of supply voltage
Treatment of unused pins
Using external clock
Power supply pins (VCC /VSS )
Pull-up/pull-down resistors
Crystal Oscillator Circuit
Turning-on Sequence of Power Supply to A/D Converter and Analog Inputs
Connection of Unused Pins of A/D Converter
Notes on turning the power on
Notes on During Operation of PLL Clock Mode
1.
Preventing latch-up
CMOS IC chips may suffer latch-up under the following conditions :
A voltage higher than VCC or lower than VSS is applied to an input or output pin.
A voltage higher than the rated voltage is applied between VCC and VSS pins.
The AVCC power supply is applied before the VCC voltage.
Latch-up may increase the power supply current drastically, causing thermal damage to the device.
In using the devices, take sufficient care to avoid exceeding maximum ratings.
For the same reason, also be careful not to let the analog power-supply voltage (AVCC, AVR) exceed the digital
power-supply voltage.
2.
Stabilization of supply voltage
A sudden change in the supply voltage may cause the device to malfunction even within the specified VCC supply
voltage operation range. Therefore, the VCC supply voltage should be stabilized.
For reference, the supply voltage should be controlled so that VCC ripple variations (peak-to-peak values) at
commercial frequencies (50 Hz/60 Hz) fall below 10
% of the standard VCC supply voltage and the coefficient of
fluctuation does not exceed 0.1 V/ms at instantaneous power switching.
3.
Treatment of unused pins
Leaving unused input pins open may result in misbehavior or latch up and possible permanent damage of the
device. Therefore they must be pulled up or pulled down through resistors. In this case those resistors should
be more than 2 k
.
Unused bidirectional pins should be set to the output state and can be left open, or the input state with the above
described connection.
4.
Using external clock
To use external clock, drive the X0 pin and leave X1 pin open.
X0
X1
MB90820B series
Open