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CHAPTER 8: PRECAUTIONS ON MOUNTING
8 P
CHAPTER
<Oscillation Circuit>
Oscillation characteristics change depending on conditions (board pattern, components used, etc.).
In particular, when using a crystal oscillator, use the oscillator manufacturer's recommended values
for constants such as capacitance and resistance.
Disturbances of the oscillation clock due to noise may cause a malfunction. Consider the following
points to prevent this:
(1) Components which are connected to the OSC1 and OSC2 terminals, such as oscillators, resistors
and capacitors, should be connected in the shortest line.
(2) As shown in the right hand figure, make a V
possible at circumscription of the OSC1 and OSC2 terminals and the
components connected to these terminals.
Furthermore, do not use this V
the oscillation system.
In order to prevent unstable operation of the oscillation circuit due to
current leak between OSC1 and V
signals on the board pattern.
<Reset Circuit>
The power-on reset signal which is input to the RESET terminal changes depending on conditions
(power rise time, components used, board pattern, etc.).
Decide the time constant of the capacitor and resistor after enough tests have been completed with the
application product.
When the built-in pull-down resistor is added to the RESET terminal by mask option, take into
consideration dispersion of the resistance for setting the constant.
In order to prevent any occurrences of unnecessary resetting caused by noise during operating,
components such as capacitors and resistors should be connected to the RESET terminal in the
shortest line.
<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
large as possible.
(2) When connecting between the V
should be connected as short as possible.
(3) Components which are connected to the V
the shortest line.
42
RECAUTIONS ON
DD
pattern for any purpose other than
DD
, please keep enough distance between OSC1 and V
SS
and V
terminals with a bypass capacitor, the terminals
DD
SS
Bypass capacitor connection example
V
DD
V
SS
terminal, such as a capacitor, should be connected in
S2
EPSON
M
OUNTING
pattern as large as
and V
terminal with patterns as short and
DD
SS
V
DD
V
SS
Sample V
pattern
DD
OSC2
OSC1
V
DD
or other
SS
S1C60N03 TECHNICAL MANUAL
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