Frequency Synthesizer using PLL

[audioguru]

The HEF4059 is the same as a CD4059 and an MC14059. They operate from a supply from 3V to 18V. They have detailed spec's in their datasheet when the supply is 5V, 10V and 15V. The HEF datasheet says to look at another "Family Specifications" datasheet to see about supply voltage effects.

They operate at a higher frequency and have a higher output current when their supply voltage is high.

 

[RadioRon]

Hi there,

I was asking one of my lecturers about the 4059 divider IC, he said the HEF4059 IC happen to work in 3 different Vin, which is 5V, 10V and 15V. Is this true? I did check the datasheet, I can't really confirm this.

the datasheet:
https://www.electro-tech-online.com/custompdfs/2009/03/14383-1.pdf

Yes, we already discussed the possibility of using a higher voltage on HEF4059 or CD4059 several posts ago. In fact, the HEF part works at any voltage up to 18 volts and the CD4049 is ok up to 15 or 20 volts depending on which manufacturer you use. The data sheet provides performance figures for HEF4059 at 5, 10 and 15 volts but it works throughout the range. In CMOS technology the higher the voltage, the faster the flip flops can toggle so the higher the input frequency. The old 4000 series were specified up to 15 volts, but 74HCxxx is designed to run at 5V and is ok up to 6V maximum.

The trouble is that the 4046 phase locked loop IC that you are working with is the 74HC4046 type and it only works up to 6V. It would not be able to interface directly to a 4059 running at 15 volts without some additional circuitry. However, I note that while the CD4059 is quite slow, the HEF4059 is much faster. The data sheet for the HEF4059 implies that it will work at 10MHz with a power supply voltage of about 7.5 volts and may work well below 7 volts.

I think that you can solve this problem by operating both the 74HC4046 and the HEF4059 at 6.0 Volts. If you find that the 4059 is struggling to reach 10MHz, you can raise the voltage of just that chip to 7 volts using a second DC power supply. In this case, we would have to add a little bit of extra circuit to interface the counter output back to the 4046 COMP input. There is no extra circuitry needed for interfacing the 4046 VCO output to the 4059, that will work fine. Signals coming from the 4059 back to the 4046 would be too high in voltage so would require a buffer amp or some sort of simple voltage limiter circuit (which is possible using two diodes and a resistor). There is a chance that this won't be needed, so I would first build it for 6 volts and see if it works up to 10Mhz.

(note: the 74HC4059 from some manufacturers say that the absolute maximum supply voltage is 7 volts and they recommend operation up to 6 volts. This means that if you are willing to risk burning out your chip, you can also turn the voltage on this IC up to almost 7 volts, carefully. If this is successfull then extra circuitry won't be needed between the two chips).

 

[yoboy]

Thanks radioron for shedding some light. At least this way I have something to start with. It seems like I don't have any other options considering the difficulties to get 74HC4059. I will start ordering HEF4059 and start some simple programming. Two diodes and a resistor is still reasonable compared to building a divide-by-N function using 4bit decade...Thank you very much...

 

[yoboy]

Radionron, I have ordered, paid and successfully received HEF4059. Yesterday, I brought it to the lab to run some tests. Much to my surprise, the IC did not output correctly... Even with all possible combination that I tried, the output was a random signal which is independent of the input frequency... Have you ever came across this situation? Or could it be the IC was defective? The IC was RM30 I don't know what other options I have left.

By the way, is it possible to input the frequency to a microcontroller and let the microcontroller do the dividing job?

 

[yoboy]

Hi radioron, and other... I would like to thank you guys for guiding me to complete the project.. yes, we have completed the project, and it has been working like a charm.. We have even completed our presentation...

thanks again...

 

[RadioRon]

You are welcome. You are a good student.

 

[the phoenix law]

hello there!

first of all, excuse me yoboy for using your thread to discuss my problem but there is a reason, it is the same problem!
i have to design a frequency synthesizer within 1 week and i found the information here very useful but still want to ask a few questions please, so i hope if you , radiron and the others kindly helped me, now let's begin
1-what was the waveform of the input/output signal ?
my guess it was a square wave, perhaps the reference frequency was based on 555 right ?
2-if i intend to design a sinusoidal frequency synthesizer (it is not a vital requirement to be sinusoidal but would be preferred) with a range of frequencies for FM detection (from 88 to 108 MHZ + the 10MHZ IF frequency) i.e from 98 to 118 Mhz, would the 74HC4046 and any of the dividers mentioned here be suitable ? i mean these high frequencies would not exceed the capture range of the 74HC4046 right ?? if there is any other problem i am not seeing, would you please suggest a solution ?

thanks in advance

 

[audioguru]

Look at the datasheet of a 74HC4046 to see that it cannot go anywhere near as high as 118MHz.

 

[the phoenix law]

@audiguru
yea you are right ... well, is there any replacement for the 74HC4046 to achieve this ?

 

[WVProfessor]

There are but most are surface mount. I am looking for a part that is through hole. Otherwise I would have to use frequency multipliers. If I don't visit this site again send me email at august04@verizon.net by end of year 2010.