CHAPTER 20 ELECTRICAL SPECIFICATIONS
User’s Manual U14826EJ5V0UD
181
System Clock Oscillator Characteristics
Ceramic or crystal oscillation (
µ
PD789860, 789860(A), 78E9860A)
(T
A
= –40 to +85
°
C, V
DD
= 1.8 to 5.5 V)
Resonator Recommended
Circuit Parameter
Conditions
MIN.
TYP.
MAX.
Unit
Oscillation frequency
(f
X
)
Note 1
V
DD
= Oscillation
voltage range
1.0 5.0
MHz
Ceramic resonator
X1
X2
V
SS
Oscillation
stabilization time
Note 2
After V
DD
reaches
oscillation voltage
range MIN.
4
ms
Oscillation frequency
(f
X
)
Note 1
1.0
5.0
MHz
Crystal resonator
X1
X2
V
SS
Oscillation
stabilization time
Note 2
30
ms
X1 input frequency
(f
X
)
Note 1
1.0
5.0
MHz
External clock
X1
X2
X1 input high-/low-
level width(t
XH
,t
XL
)
85
500
ns
Notes. 1.
Indicates only oscillator characteristics. Refer to
AC Characteristics
for instruction execution time.
2.
Time required to stabilize oscillation after reset or STOP mode release.
Caution When using a ceramic or crystal oscillator, wire as follows in the area enclosed by the broken
lines in the above figures to avoid an adverse effect from wiring capacitance.
• Keep the wiring length as short as possible.
• Do not cross with other signal lines.
• Do not route the wiring near a signal line through which a high fluctuating current flows.
• Always make the ground point of the oscillator capacitor the same potential as V
SS
.
• Do not ground the capacitor to a ground pattern through which a high current flows.
• Do not fetch signals from the oscillator.
Remark
For the resonator selection and oscillator constant of the
µ
PD78E9860A, customers are required to
either evaluate the oscillation themselves or apply to the resonator manufacturer for evaluation.
Содержание PD789860
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