frequency synthesizer

[oufa]

hi
any one can tell me aname of a PLL IC so i can use as afrequency synthesizer?
also please tell me how it works and the meaning of 2 input phase detector as there is an ic which has aspecification of 2 input phase detector
thanks so much for your patiencs and help

[dlgoff]

Well, a PLL needs two inputs in order to obtain a phase error signal.
http://en.wikipedia.org/wiki/Phase-locked_loop#Analog_phase-locked_loop
Here's a list of PLL Synthesizers IC (http://www.fujitsu.com/global/services/microelectronics/product/assp/rf/pll/)

[oufa]

sorry you misunderstood me
i mean that there is aphase detector of 2 inputs beside the output of the VCO
i know that apll compares acertain input frequency with the frequency of vco and the diffrence or error is amplified and filterd so as to be applied as an input to the vco
so on;y one input exists with the output of vco
but i saw ics which have 2 inputs beside the feed back signal and i dont know what is it ?

[dlgoff]

You mean something like this?
Dual Serial Input PLL Frequency Synthesizer (www.fujitsu.com/downloads/MICRO/fma/pdf/e421339.pdf)
The MB15U10 has two PLL frequency synthesizer circuits on a single chip: one for transmission and the other for reception (PLL1 and PLL2).

[Averagesupernova]

I've never heard of a phase detector with 3 inputs if that is what you are wondering.
-
Which IC is it that you noticed 2 inputs to the phase detector besides the VCO? I'd like a part# so I could look up a data sheet.

[Bob S]

The 4030 MOSFET quad 2-input exclusive OR can be used as a digital PLL phase detector. See

http://www.datasheetcatalog.org/datasheets/208/206742_DS.pdf

Also look up the NE565 PLL chip, which is a classic PLL chip

http://pdf1.alldatasheet.com/datasheet-pdf/view/118262/ETC/NE565N.html

Bob S