RTC Crystal Problem in Capacitor based Power Supply

I got a problem when using a PCF8563 RTC with a Capacitor based power supply for 5V. The circuit created for the purpose is shown in the attached file. The issue is with the accuracy. When the same circuit is connected to a pure 5V dc supply from an external power source, the RTC gives me exactly 1Hz pulse at the ClKOUT pin of the IC, and the time flow is correct.

But when its powered from the direct line supply, the capacitor power supply is giving exactly 5V and rest of the parts are working fine (a PIC controller) . But the accuracy of the RTC is gone worse, its get delayed. When I noticed , the ClKOUT pin, its waveform is represented in the image file attached . Its seems like a huge delayed oscillator startup.

What is happening in this case, expecting your help

Thanks in advance
Geo

Hi,

What happens if you use a conventional transformer power supply and 5v regulator ?

The 5V alternative supply which I used is a transformer - 5V regulator type . In that case, the RTC works perfect and giving exactly a 1Hz pulse.

That may be due to large ripples from Capacitor type dropper power supply... may be this RTC is not immune to harsh/unstable power supplies..try adding a 100nF decoupling capacitor as RTC I.C supply pins...and also increase the bulk filter capacitor`s value at Zener diode...

Right now a 470uF capacitor is added across the zener diode, and an additional 100nF capacitor is already added beside to the RTC's first 100nF filter capacitor.