Datasheet

78K0/Kx2-L CHAPTER 28 ELECTRICAL SPECIFICATIONS

R01UH0028EJ0400 Rev.4.00 743

Sep 27, 2010

Caution The pins mounted depend on the product. Refer to Caution 2 at the beginning of this chapter.

XT1 Oscillator Characteristics

A = −40 to +85°C, 1.8 V ≤ VDD ≤ 5.5 V, VSS = AVSS = 0 V)

Resonator Recommended Circuit Parameter Conditions MIN. TYP. MAX. Unit

Crystal

resonator

XT1

XT2

XT1 clock oscillation

frequency (f

XT)

Note

AMPHXT = 0 32 32.768 35 kHz

Note Indicates only oscillator characteristics. Refer to AC Characteristics for instruction execution time.

Cautions 1. When using the XT1 oscillator, wire as follows in the area enclosed by the broken lines in the above

figure 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

SS.

• Do not ground the capacitor to a ground pattern through which a high current flows.

• Do not fetch signals from the oscillator.

2. The XT1 oscillator is designed as a low-amplitude circuit for reducing power 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 XT1 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.