MC 145152 synthesizer

mc145152

Hello dear friends:

I decide to build a VHF synthesizer (210 Mhz to 270 Mhz) using MC145152-2 & a minicircuits POS400 VCO (0 to 16v tuning voltage). I have been studying about the integer-n synthesizers and different types of loop filters used in plls for a while. but I still have some problems with the MC145152 & I will really appreciate it if you help me with them.
1.Are the output pulses of phase detector of MC145152-2 (Φv & Φr) current pulses or volatage pulses & are they the outputs of a charge pump or not?
2.How should I consider the transfer function of MC145152 phase detector in my calculations?
3.How should I design my active first or second order loop filter based on this two output phase detector (Φv & Φr of MC145152) & how will be its transfer function form (Vo(s)/Vi(s) or Vo(s)/Ii(s))?
4.Is there any online tutorial about designing synthesizers with MC145152 or any tutorial about designing loop filters for phase detectors like the one in MC145152?
5.Is there any software that I can use to design a loop filter based on the specific charecteristics of my synthesizer & VCO?

Thank you very much for your answers.

pll 145152

THat Freescale part is crusty and old. I'd recommend sampling some parts from National Semiconductor or Analog Devices to get something a little more current. You really want to use something with a charge pump output, which that part doesn't have. National semiconductor has a nice app note on PLL design on their web page @ wireless.national.com .

Dave
www.keystoneradio.com

mc-145152

Hello dear RFdave:
first I want to thank you for your answer.
I am working on this project as my final university project & the problem is that the
university doesnt let me to use such advanced synthesizer ICS (I mean that they want me to build this synthesizer as discrete as I can & use VCO, phase detector,frequency divider & etc as different modules not integrated in one chip like those from analog devices) so the best choice I could find is MC145152 which its programing is also very easy. finally I will really appreciate it if you answer my above questions & give me some information about MC145152.
By the way, dont you know any article which describes practically the process of designing loop filters compatible with MC145152?

with respect
Yashar

145152

Interesting teaching approach.

Take a look at the data sheet,
www.freescale.com/files/rf_if/doc/data_sheet/MC145151-2.pdf

There are a couple of pages there that cover loop filter design. I'd poke around on the Freescale website to see that sort of design assistance they provide. I've never designed a PLL with a voltage output PFD, I'll have to do some digging to figure out what's going on there.

Dave
www.keystoneradio.com

mc145151 tutorial

Hi again:
Dear Dave I had seen the datasheet of MC145152 before. In that document freescale has offered an active loop filter with the equations of damping factor (zeta) & natural frequency (ωn). if i use this loop filter, how should I define damping factor & natural frequency to make my synthesizer work well?
By the way whats your opinion about using HEF4750 & HEF4751 instead of MC145152?

Thanks

analog synth project

Damping Factor and Natural frequency are used to set the loop bandwidth and the settling time. TO start with, you should use a Damping factor of 0.707, and a natural bandwidth of Fcomp/20. This should give you a stable loop with a narrow enough bandwidth that you shouldn't see any reference spurs. Since your VCO need's an tuning voltage of 0 to 16 volts, you will have to make sure that the Op amp output swing is that large.

Dave

programação mc 145152

Hi Dave:

Thanks a lot for all the information & help you gave me.
I have designed the loop filter according to the values you said & I am going to test it practically. I wish it will work well. I will tell you the result soon.

Yashar

mc145152 vco

Hello Dave & all other friends:

I built the synthesizer on a dot matrix PCB board & I replaced the resistor in the feedback branch of the OPAMP of the loop filter (R2) with a potentiometer.
fortunately all the frequencies in the band 210 Mhz to 270 Mhz are made by the synthesizer & by adjusting the potentiometer I can achieve -60dbc/HZ phase noise in whole of the band.
now i want to know if building the circuit on a designed PCB instead of a dot matrix one & covering the circuit with a metal box will improve the phase noice noticeably.

Thanks for the tips.
Yashar

vhf synthesizer datasheet

Putting it on a PCB could either help or hurt. It's more likely to help the performance if you do a good job with the layout. It also might help to determine the value of the potentiometer, and replace it with a resistor.

Dave
www.keystoneradio.com

mc 145152 pll

Hello all viewers & dear Dave:

I have approximately done my synthesizer project & now I am going to write my thesis for it. therefore I am looking for a good online document about integer-N synthesizer theory for example an IEEE article about integer-n synthesizers architecture & analysis.so it will be appreciated if you introduce me such a document or give me an IEEE article in this field.

Thank you very much for all of your helps & answers.
Yashar