PLL to VCO

[hantto]

2½ year old post...

 

[Pilot]

SAA1057...

**broken link removed**

http://www.donberg.ie/descript/s/saa1057.htm

**broken link removed**

:lol:

 

[hantto]

Thanks, but it would be to expensive to order a single part! So I still ask if someone would help me design a PLL circuit without this part or a VCO.

 

[kinjalgp]

For PLL/VCO a cheaper solution would be LM565/LM567 from National semiconductor.

 

[mictester]

For PLL/VCO a cheaper solution would be LM565/LM567 from National semiconductor.

You've just looked up PLL on Google and posted the first things you've found! The 565 is a really good PLL IC for AUDIO frequencies but is useless for RF work. The 567 is just a tone decoder IC and cannot be used in a PLL frequency controller.

There are many more modern ICs available for RF PLL use - the SAA1057 is a very old device, and becoming difficult to obtain (Philips haven't made them since 1996). The LMX series are current and available from most suppliers - they are I2C programmed so PIC code for them is trivial.

If you want an RF frequency controller PLL, you can easily make one from cheap, easily obtained standard 74HC CMOS ICs - the 74HC4060 is ideal as your crystal oscillator, the 74HC4059 for the programmable divider, and the 74HC4046 for the phase comparator. You'll need a reference crystal (4 MHz or 6.4 MHz are easiest to work with) and you'll have to calculate the loop filter time constants - really easy if you use the 4046 data sheet on the Philips website.

If you can't get the 74HC4059, you can use a 74HC4040 with a few diodes and a resistor to program the division ratio - I'll leave it as an exercise for the reader to work out how to do it!

Mike

 

[ee.prasad]

Do you have tutorial on SAA1057

I have a radio tuner to repair with SAA1057 Ic
Please post links regarding SAA1057