how to use a phase lock loop

[pierre2030]

-can u show me how to use a phase lock loop?can u tell me how the pin to be connected?i am using hcf4046B phase lock loop.i
-this PLL will be using with pic16f877a

thank u

 

[IanP]

"CMOS Phase-Locked-Loop Applications Using the
CD54/74HC/HCT4046A and CD54/74HC/HCT7046A"
http://www.etc.tuiasi.ro/cin/Downloads/pll/PLL-4046.pdf

Regards,
IanP

 

[rkodaira]

For what purpose will you use a 4046 with th 16F877 ?

A phase locked loop is used to synthesize frequency, i.e. multiply frequency. Some PICs have an internal PLL to multiply the frequency of a crystal to be used as a main clock. If it is the case, the 4046 has a maximum operating frequency output of 1MHz @ Vdd = 5V, which is too low for the PIC clock (you can use a 20MHz crystal directly).

If it is not the case and you just try to multiply the frequency of a signal from PIC, just connect the signal to pin 14 (signal in) of 4046, choose pin 2 or 13 for phase comparator, you should calculate a RC low pass filter (to pin 9), choose some componentes to VCO (Capacitors and resistors), use a frequency divider counter (between pins 3 and 4). Better take a look at the 4046 datasheet (search at Philips site).