PCF8563

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APPLICATION CIRCUIT

Method 1: Fixed OSCI capacitor — By evaluating the average capacitance necessary for

the application layout a fixed capacitor can be used. The frequency is best measured via the

32.768 kHz signal available after power-on at the CLKOUT pin. The frequency tolerance

depends on the quartz crystal tolerance, the capacitor tolerance and the device-to-device

Average deviations of ±5 minutes per year can be easily achieved.

Method 2: OSCI trimmer — The oscillator is tuned to the required accuracy by adjusting a

trimmer capacitor on pin OSCI and measuring the 32.768 kHz signal available after

power-on at the CLKOUT pin.

Method 3: OSCO output — Direct output measurement on pin OSCO (accounting

for test probe capacitance).