UPD78F0138 NEC, UPD78F0138 Datasheet - Page 509

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

Ring-OSC Oscillator Characteristics
(T
Subsystem Clock Oscillator Characteristics
(T
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
Remark For the resonator selection and oscillator constant, customers are requested to either evaluate the
On-chip Ring-OSC oscillator
Crystal
resonator
External clock
A
A
Resonator
= −40 to +125°C, 3.3 V ≤ V
= −40 to +125°C, 3.3 V ≤ V
2. The subsystem clock oscillator is designed as a low-amplitude circuit for reducing power
oscillation themselves or apply to the resonator manufacturer for evaluation.
Resonator
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.
consumption, and is more prone to malfunction due to noise than the X1 oscillator. Particular
care is therefore required with the wiring method when the subsystem clock is used.
Recommended Circuit
V
XT2
SS
C4
CHAPTER 31 ELECTRICAL SPECIFICATIONS ((A2) GRADE PRODUCTS)
Rd
XT2
C3
XT1
XT1
DD
DD
Oscillation frequency (f
= EV
= EV
DD
DD
Oscillation frequency
(f
XT1 input frequency
(f
XT1 input high-/low-level
width (t
Parameter
XT
XT
≤ 5.5 V, 3.3 V ≤ AV
≤ 5.5 V, 3.3 V ≤ AV
)
)
Note
Note
User’s Manual U16228EJ2V0UD
Parameter
XTH
, t
XTL
R
)
)
REF
REF
≤ V
≤ V
DD
DD
Conditions
, V
, V
Conditions
SS
SS
= EV
= EV
SS
SS
= AV
= AV
SS
SS
MIN.
MIN.
120
32
32
12
= 0 V)
= 0 V)
32.768
TYP.
TYP.
240
SS
MAX.
MAX.
38.5
495
35
15
.
Unit
kHz
Unit
kHz
kHz
µ
s
509