Document Number: 002-04578 Rev. *A
Page 16 of 64
MB90910 Series
5.
Power supply pins (V
CC
/V
SS
)
■
If there are multiple V
CC
and V
SS
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 malfunction such 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 V
CC
and V
SS
pins to the power supply and ground externally.
■
Connect V
CC
and V
SS
pins 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
F as a bypass capacitor between V
CC
pin and V
SS
pin in the vicinity of V
CC
and V
SS
pins of the device.
6.
Pull-up/down resistors
■
The MB90910 series does not support internal pull-up/down resistors (Port 2 : built-in pull-up resistors) . Use external components
where needed.
7.
Crystal oscillator circuit
Noises around X0 or X1 pin may be possible causes of malfunctions. Make sure to provide bypass capacitors via shortest distance
from X0, X1 pins, crystal oscillator (or ceramic resonator) and ground lines, and make sure, that lines of oscillation circuit do not cross
the lines of other circuits.
It is highly recommended to provide a printed circuit board artwork surrounding X0 and X1 pins with a ground area for stabilizing the
operation. Please ask the crystal maker to evaluate the oscillational characteristics of the crystal and this device.
8.
Turning-on sequence of power supply to A/D converter and analog inputs
Make sure to turn on the A/D converter power supply (AV
CC
and AVR) and analog inputs (AN0 to AN15) after turning-on the digital
power supply (V
CC
) .
Turn-off the digital power after turning off the A/D converter power supply and analog inputs. In this case, make sure that the voltage
does not exceed AVRH or AV
CC
.
9.
Connection of unused pins of A/D converter if A/D converter is not used
Connect unused pins of A/D converter to AV
CC
V
CC
, AV
SS
AVR
V
SS
.
10. Notes on energization
To prevent the internal regulator circuit from malfunctioning, set the voltage rise time during energization at
50
s or more (0.2 V to 2.7 V) .
V
CC
V
CC
V
CC
V
CC
V
CC
V
SS
V
SS
V
SS
V
SS
V
SS
MB90910
Series
