aPPenDiX e SuMMaRY OF nOTeS
aP-e-6
Seiko epson Corporation
S1C63003/004/008/016 TeChniCal Manual
(Rev. 1.1)
Power supply circuit
• Sudden power supply variation due to noise may cause malfunction. Consider the following points to prevent this:
(1) The power supply should be connected to the V
DD
and V
SS
terminals with patterns as short and large as
possible.
(2) When connecting between the V
DD
and V
SS
terminals with a bypass capacitor, the terminals should be
connected as short as possible.
V
DD
V
SS
Bypass capacitor connection example
V
DD
V
SS
(3) Components which are connected to the V
D1
,V
OSC
and V
C1
–V
C3
terminals, such as capacitors, should be
connected in the shortest line. In particular, the V
C1
–V
C3
voltages affect the display quality.
• Do not connect anything to the V
C1
–V
C3
terminals when the LCD driver is not used.
arrangement of signal lines
• In order to prevent generation of electromagnetic induction noise caused
by mutual inductance, do not arrange a large current signal line near the
circuits that are sensitive to noise such as the oscillation unit and analog
input unit.
• When a signal line is parallel with a high-speed line in long distance or
intersects a high-speed line, noise may generated by mutual interference
between the signals and it may cause a malfunction.
Do not arrange a high-speed signal line especially near circuits that are
sensitive to noise such as the oscillation unit and analog input unit.
Output terminals
• When an output terminal is used to drive an external component that con-
sumes a large amount of current, the operation of the external component
affects the built-in power supply circuit of this IC and the output voltage
may vary. When driving a bipolar transistor by a periodic signal such as
the BZ or timer output in particular, it may cause variations in the voltage
output from the LCD system voltage circuit that affects the contrast of
the LCD display. To prevent this, separate the traces on the printed circuit
board. Put one between the power supply and the IC's V
DD
and V
SS
termi-
nals, and another between the power supply and the external component
that consumes the large amount of current. Furthermore, use an external
component with as low a current consumption as possible.
Precautions for Visible Radiation (when bare chip is mounted)
• Visible radiation causes semiconductor devices to change electrical characteristics. It may cause the IC to
malfunction. When developing products, consider the following precautions to prevent malfunctions caused
by visible radiation.
(1) Design the product and bond the IC on the board so that it is shielded from visible radiation in actual
use.
(2) The inspection process of the product needs an environment that shields the IC from visible radiation.
(3) Shield not only the face of the IC but the back and side as well.
(4) After the shielded package has been opened, the IC chip should be bonded on the board within one week.
If the IC chip must be stored after the package has been opened, be sure to shield the IC from visible
radiation.
V
DD
V
SS
Piezo
BZ
C
P
Example: Buzzer output circuit
+
OSC4
OSC3
V
SS
Large current signal line
High-speed signal line
Prohibited pattern example