MB90385 Series
•
Sequence of Turning on Power of A/D Converter and Applying Analog Input
• Be sure to turn on digital power (Vcc) before applying signals to the A/D converter and applying analog input
signals (AN0 to AN7 pins).
• Be sure to turn off the power of A/D converter and analog input before turning off the digital power source.
• Be sure not to apply AVR exceeding AVcc when turning on and off. (No problems occur if analog and digital
power is turned on and off simultaneously.)
•
Handling Pins When A/D Converter is Not Used
• If the A/D converter is not used, connect the pins under the following conditions: “AVcc=AVR=Vcc,” and
“AVss=Vss”
•
Note on Turning on Power
• For preventing malfunctions on built-in step-down circuit, maintain a minimum of 50
µs
of voltage rising time
(between 0.2 V and 2.7V) when turning on the power.
•
Stabilization of supply voltage
• A sudden change in the supply voltage may cause the device to malfunction even within the specified V
CC
supply voltage operating range. Therefore, the V
CC
supply voltage should be stabilized.
For reference, the supply voltage should be controlled so that V
CC
ripple variations (peak-to-peak values) at
commercial frequencies (50 Hz to 60 Hz) fall below 10% of the standard V
CC
supply voltage and the coefficient
of fluctuation does not exceed 0.1 V/ms at instantaneous power switching.
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