IN1307
OSCILLATOR CIRCUIT
IN1307 uses an external 32.768kHz crystal. The oscillator circuit does not require any exter-
nal resistors or capacitors to operate. Table specifies several crystal parameters for the external
crystal.
CRYSTAL SPECIFICATIONS*
Parameter
Nominal Frequency
Series Resistance
Load Capacitance
Symbol
fo
Min
Typ
Max
Unit
kHz
k
32.768
ESR
CL
45
12.5
pF
*The crystal, traces, and crystal input pins should be isolated from RF generating signals.
Application Note : Crystal Considerations for Real-Time Clocks for additional specifications. See 12
page.
CLOCK ACCURACY
The accuracy of the clock is dependent upon the accuracy of the crystal and the accuracy of
the match between the capacitive load of the oscillator circuit and the capacitive load for which the
crystal was trimmed. Additional error will be added by crystal frequency drift caused by tempera-
ture shifts. Externalcircuit noise coupled into the oscillator.
OSCILLATOR CIRCUIT SHOWING INTERNAL BIAS NETWORK
.
Figure shows a functional schematic of the oscillator circuit. If using a crystal with the specified
characteristics, the startup time is usually less than one second.
2013, December, Ver.04
6
IKSEMICON [ IK SEMICON CO., LTD ]
