©NEC Electronics Corporation 2004

78K0/KF2

ZUD-CC-04-0129-E

Data Published Oct 2004 N CP(K)

Ring-OSC Oscillator Characteristics

(TA = -40 to +85

°C, 1.8 V ≤ VDD = EVDD ≤ 5.5 V, 2.3 V ≤ AVREF ≤ VDD= EVDD, VSS = EVSS = AVSS = 0 V)

Resonator

Parameter

Conditions

MIN.

TYP.

MAX.

Unit

2.7 V

≤ VDD ≤ 5.5 V

7.6

Note2

8.0

Note2

8.4

Note2

8 MHz Ring-OSC oscillator

High-speed Ring-OSC

Oscillation

frequency(fRH)

Note1

1.8 V

≤ VDD ≤ 5.5 V

T.B.D

8.0

Note2

T.B.D

MHz

2.7 V

≤ VDD ≤ 5.5 V

216

240

264

240 kHz Ring-OSC oscillator

Low-speed Ring-OSC

Oscillation frequency(fRL)

1.8 V

≤ VDD ≤ 5.5 V

T.B.D

240

T.B.D

kHz

Note 1. Indicates only oscillator characteristics.

Refer to AC Characteristics for instruction execution

time.

2. This is the frequency in the case of RSTS(RCM.7)=1. This is 5 MHz(TYP.) in the case of

RSTS=0.

Subsystem Clock Oscillator Characteristics

(TA = -40 to +85

°C, 1.8 V ≤ VDD = EVDD ≤ 5.5 V, 2.3 V ≤ AVREF ≤ VDD= EVDD, VSS = EVSS = AVSS = 0 V)

Resonator

Recommended

Circuit

Parameter

Conditions

MIN.

TYP.

MAX.

Unit

Crystal resonator

Oscillation

frequency(fSUB)

Note

32

32.768

35

kHz

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 VSS.

• 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 power

consumption, and is more prone to malfunction due to noise than the high-speed 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.

XT1

XT2

C4

C3

Rd

VSS