NEC 78K0/KD1 Series User Manual page 411

CHAPTER 27 ELECTRICAL SPECIFICATIONS (TARGET VALUES)
Ring-OSC Oscillator Characteristics
= − − − − 40 to +85° ° ° ° C, 2.7 V ≤ ≤ ≤ ≤ V
(T
A
Resonator
On-chip Ring-OSC oscillator
Subsystem Clock Oscillator Characteristics
= − − − − 40 to +85° ° ° ° C, 2.7 V ≤ ≤ ≤ ≤ V
(T
A
Resonator Recommended Circuit
IC
Crystal
(V ) XT2
PP
resonator
Rd
C4
XT2
External clock
Note Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.
Cautions 1. When using the subsystem clock 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 the wiring with the 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
• • • • Do not ground the capacitor to a ground pattern through which a high current flows.
• • • • Do not fetch signals from the oscillator.
2. The subsystem clock oscillator is designed as a low-amplitude circuit for reducing current
consumption, and is more prone to malfunction due to noise than the main system clock
oscillator. Particular care is therefore required with the wiring method when the subsystem
clock is used.
Remark For the resonator selection and oscillator constant, customers are requested to either evaluate the
oscillation themselves or apply to the resonator manufacturer for evaluation.
≤ ≤ ≤ ≤ 5.5 V, 2.7 V ≤ ≤ ≤ ≤ AV
= EV
DD DD
Parameter
Oscillation frequency (f )
R
≤ ≤ ≤ ≤ 5.5 V, 2.7 V ≤ ≤ ≤ ≤ AV
= EV
DD DD
Parameter
Oscillation frequency
XT1
Note
(f )
XT
C3
XT1
XT1 input frequency
Note
(f )
XT
XT1 input high-/low-level
width (t , t )
XTH XTL
Preliminary User's Manual U16315EJ1V0UD
≤ ≤ ≤ ≤ V
, V = EV = AV
REF DD SS SS
Conditions
≤ ≤ ≤ ≤ V
, V = EV = AV
REF DD SS SS
Conditions
= 0 V)
SS
MIN. TYP. MAX. Unit
120 240 480 kHz
= 0 V)
SS
MIN. TYP. MAX. Unit
32 32.768 35 kHz
32 38.5 kHz
µ s
12 15
.
SS
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