UPD78F1502AGK-GAK-AX Datasheet, PDF (897/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 31 ELECTRICAL SPECIFICATIONS
XT1 Oscillator Characteristics
(TA = −40 to +85°C, 1.8 V ≤ VDD = EVDD ≤ 5.5 V, VSS = EVSS = AVSS = 0 V)
Resonator
Recommended
Circuit
Items
Conditions
Crystal resonator
VSS XT2 XT1
Rd
XT1 clock oscillation
frequency (fXT)^Note
C4 C3
MIN. TYP. MAX. Unit
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 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 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.
R01UH0004EJ0501 Rev.5.01
881
Jun 20, 2011