Document Number: 002-04721 Rev.*A
Page 34 of 74
MB966B0 Series
13.8 Pin handling when not using the A/D converter
If the A/D converter is not used, the power supply pins for A/D converter should be connected such as AV
CC
= V
CC
, AV
SS
= AVRH =
AVRL = V
SS
.
13.9 Notes on Power-on
To prevent malfunction of the internal voltage regulator, supply voltage profile while turning the power supply on should be slower
than 50
s from 0.2V to 2.7V.
13.10 Stabilization of power supply voltage
If the power supply voltage varies acutely even within the operation safety range of the V
CC
power supply voltage, a malfunction may
occur. The V
CC
power supply voltage must therefore be stabilized. As stabilization guidelines, the power supply voltage must be
stabilized in such a way that V
CC
ripple fluctuations (peak to peak value) in the commercial frequencies (50Hz to 60Hz) fall within
10% of the standard V
CC
power supply voltage and the transient fluctuation rate becomes 0.1V/
s or less in instantaneous
fluctuation for power supply switching.
13.11 Serial communication
There is a possibility to receive wrong data due to noise or other causes on the serial communication.
Therefore, design a printed circuit board so as to avoid noise.
Consider receiving of wrong data when designing the system. For example apply a checksum and retransmit
the data if an error occurs.
13.12 Mode Pin (MD)
Connect the mode pin directly to Vcc or Vss pin. 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 pin to Vcc or Vss pin and provide a low-impedance connection.
