MB90P678PF Просмотр технического описания (PDF) - Fujitsu

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MB90P678PF

16-bit Proprietary Microcontroller

Fujitsu 

MB90670/675 Series

s HANDLING DEVICES

1. Make Sure that the Voltage not Exceed the Maximum Rating (to Avoid a Latch-up).

In CMOS ICs, a latch-up phenomenon is caused when an voltage exceeding VCC or an voltage below VSS is

applied to input or output pins or a voltage exceeding the rating is applied across VCC and VSS.

When a latch-up is caused, the power supply current may be dramatically increased causing resultant thermal

break-down of devices. To avoid the latch-up, make sure that the voltage not exceed the maximum rating.

In turning on/turning off the analog power supply, make sure the analog power voltage (AVCC, AVRH) and analog

input voltages not exceed the digital voltage (VCC).

2. Connection of Unused Pins

Leaving unused pins open may result in abnormal operations. Clamp the pin level by connecting it to a pull-up

or a pull-down resistor.

3. Notes on Using External Clock

In using the external clock, drive X0 pin only and leave X1 pin unconnected.

• Using external clock

Open

X0

X1

MB90670/675 series

4. Power Supply Pins

In products with multiple VCC or VSS pins, the pins of a same potential are internally connected in the device to

avoid abnormal operations including latch-up. However, connect the pins external power and ground lines to

lower the electro-magnetic emission level and abnormal operation of strobe signals caused by the rise in the

ground level, and to conform to the total current rating.

Make sure to connect VCC and VSS pins via lowest impedance to power lines.

It is recommended to provide a bypass capacitor of around 0.1 µF between VCC and VSS pin near the device.

5. Crystal Oscillator Circuit

Noises around X0 or X1 pins may be possible causes of abnormal operations. Make sure to provide bypass

capacitors via shortest distance from X0, X1 pins, crystal oscillator (or ceramic resonator) and ground lines, and

make sure, to the utmost effort, that lines of oscillation circuit not cross the lines of other circuits.

It is highly recommended to provide a printed circuit board art work surrounding X0 and X1 pins with an grand

area for stabilizing the operation.

6. Turning-on Sequence of Power Supply to A/D Converter and Analog Inputs

Make sure to turn on the A/D converter power supply (AVCC, AVRH, AVRL) and analog inputs (AN0 to AN7) after

turning-on the digital power supply (VCC).

Turn-off the digital power after turning off the A/D converter supply and analog inputs. In this case, make sure

that the voltage not exceed AVRH or AVCC (turning on/off the analog and digital power supplies simultaneously

is acceptable).

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