Help me choose between studying PLL or ADC/DAC

[Bryan79]

pll for dac

Sorry to ask a personal question.

I have been sent to Toshiba Japan for Analog IC design since last year November. Before I go to Japan, they told me I am going to learn PLL design. But when I am in Japan, they changed. So I asked for ADC/DAC design, but I didn't get it. I end up doing Pierce Oscillator design until now. I have 10 months left for my training.

Hence, I told my supervisor that I want to learn PLL on myself (thru self study and research) since they are unable to provide me the necessary training. Then, they decided to let me do ADC/DAC design. They said I can choose between PLL (self learning) or ADC/DAC design (Toshiba circuit is available for reference and there are people who know about this design). There is no technical PLL people around in my department.

I feel that Oscillator is more related to PLL and if I switch to ADC/DAC training, my training will looked a bit akward and unrelated. I think if they mean to let me do SAR ADC/DAC, they should have let me do it at the first place, not spending my past few months doing the oscillator.

Now, I am in dilemma and need some advice. Should I go for PLL or ADC/DAC design? Is PLL design that useless compared to ADC/DAC?

 

[Btrend]

Re: PLL or DAC/ADC?

In my opinion, doing things deep is more important than doing things wide.
There are too many "analog circuit" for u to study in the future, it's endless.
So, why hurry ?
and by the way, most BIG company will not employ a guy knowing "everything", only small company need this kind of people.

 

[dog1357]

PLL or DAC/ADC?

For what i know so far, industry prefer people with real project experience, and it takes quite long to finish one project, so no need to worry too much,just take this one year as a good experience, there are too much waiting for you.

 

[yibinhsieh]

Re: PLL or DAC/ADC?

I think either one is OK for your training. PLL and ADC/DAC are very common blocks in many products. Like wireless baseband transciver, DVD applications, settop box, and etc. For mixed-signal design, I think it is helpful if someone can guide you. And if you do yourself, I think you may lose direction.

Yibin.

 

[Bryan79]

Re: PLL or DAC/ADC?

I would like to say thanks to all people here who gave me sincere advice. I have spent like 2 weeks researching up and down on PLLs, printing and downloading whatever useful material and reading them.

I believe that designing a PLL is a VERY difficult thing. It is a very complex because it involves control system theory and analog design. This is not too difficult. I think the MOST difficult thing for me is the concept of PHASE NOISE and JITTER. It is too abstract and difficult to understand.

If I am not mistaken, designing PLL needs to simulate the control system (closed loop) and the phase noise / jitter. I have no idea how to simulate phase noise and jitter.

Yibin is right. I think if I am going to do PLL without an expert guidance, I think I will be lost half way. I will be like those people who start posting FAQ in the forum, asking how to this and how to that. lol. This is in fact stupid because this is meant to be a training (trained by people), not a full self research thing. Even a PHD student has at least one supervisor to guide them. What is more, I have only 10 months left.

I think I GIVE UP the idea of PLL although it is VERY interesting and TEMPTING. If only I wish I have met with someone with such experty to teach me. Unfortunately, there isn't anyone in TOSHIBA in my department. Sad indeed.

On the other hand, I will be focus my training in new area of SAR if nothing goes wrong. Most probably designing the control logic circuit and DAC/ADC. As for the pierce oscillator, I believe it is not totally a waste, as I do learn some feedback theories from there too, though not much.

 

[layes2]

Re: PLL or DAC/ADC?

PLL or adc of course adc

 

[feier0251]

PLL or DAC/ADC?

you'd better start at adc design ,because pll is very diffcult to design,the simulation and layout are different things.

you should study the design of mixed signal circuit for several years that you can start to design pll.

regards