MB90860E Ver la hoja de datos (PDF) - Fujitsu
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MB90860E Datasheet PDF : 67 Pages
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MB90860E Series
■ HANDLING DEVICES
1. Preventing latch-up
CMOS IC 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.
For the same reason, also be careful not to let the analog power-supply voltage (AVCC, AVRH) exceed the digital
power-supply voltage.
2. Handling 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 kΩ .
Unused bidirectional pins should be set to the output state and can be left open, or the input state with the above
described connection.
3. Power supply pins (VCC/VSS)
• If there are multiple VCC and VSS pins, from the point of view of device design, pins to be of the same potential
are connected the inside of the device to prevent such malfunctioning as latch up.
To reduce unnecessary radiation, prevent malfunctioning of the strobe signal due to the rise of ground level,
and observe the standard for total output current, be sure to connect the VCC and VSS pins to the power supply
and ground externally.
• Connect VCC and VSS to the device from the current supply source at a low impedance.
• As a measure against power supply noise, connect a capacitor of about 0.1 µF as a bypass capacitor between
VCC and VSS in the vicinity of VCC and VSS pins of the device
Vcc
Vss
Vcc
Vss
Vss
MB90860E
Vcc
Series
Vcc
Vss
Vss
Vcc
4. Mode Pin (MD0 to MD2)
Connect the mode pin directly to VCC or VSS pins.
To prevent the device unintentionally entering test mode due to noise, lay out the printed circuit board so as to
minimize the distance from the mode pins to VCC or VSS pins and to provide a low-impedance connection.
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