
CHAPTER 21 ELECTRICAL SPECIFICATIONS
User’s Manual U13952EJ3V1UD
279
Main System Clock Oscillator Characteristics (TA =
40 to +85°C, VDD = 1.8 to 5.5 V)
Resonator
Recommended Circuit
Parameter
Conditions
MIN.
TYP.
MAX.
Unit
Oscillation frequency
(fX)
Note 1
VDD = Oscillation voltage
range
1.0
5.0
MHz
Ceramic
resonator
X2
X1
VSS0
C2
C1
Oscillation stabilization
time
Note 2
After VDD has reached MIN. of
oscillation start voltage
4
ms
Oscillation frequency
(fX)
Note 1
1.0
5.0
MHz
VDD = 4.5 to 5.5 V
10
ms
Crystal
resonator
X2
X1
VSS0
C2
C1
Oscillation stabilization
time
Note 2
VDD = 1.8 to 5.5 V
30
ms
X1 input frequency
(fX)
Note 1
1.0
5.0
MHz
X1
X2
X1 input high-/low-level
widths (tXH, tXL)
85
500
ns
X1 input frequency
(fX)
Note 1
VDD = 2.7 to 5.5 V
1.0
5.0
MHz
External
clock
X1
X2
OPEN
X1 input high-/low-level
widths (tXH, tXL)
VDD = 2.7 to 5.5 V
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.
Use a resonator whose
oscillation is stabilized within the oscillation wait time.
Cautions 1. When using the main system 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 VSS0.
Do not ground the capacitor to a ground pattern through which a high current flows.
Do not fetch signals from the oscillator.
2. When the main system clock is stopped and the device is operating on the subsystem clock,
wait until the oscillation stabilization time has been secured by the program before switching
back to the main system clock.
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.