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Thank you Vfone!
If the company said that I will be trained to design LDMOS transistors, but I know nothing about designing transistors, so what does the company mean? It is a good chance or not? And Could anyone kindly give me some book about this such as design process, which aspects should I learn?
Thank you!
I would gather a large amount of advice before taking this job. There are thousands of people in the world who could design such transistors. Why do they not take such a job?
The LDMOS transistors are presently the best RF power transistors for high power applications.
They reache higher power, higher frequency and still giving quite good efficiency.
They are a strong candidate to replace many vacuum tubes still in operation.
I believe it is a good chance for u to go to work with those freescale/motorola guys. You will certainly find very competent people there.
Are you going to design the transistors themselfs or the test amplifiers that are used to evaluate the performance of the transistors?
Both areas are very valuable in the market. I still believe that amplifier design is more important in terms of other job oportunieites after than the transistor design.
Thank you all above!
Hi,Vfone:
Thanks for your PDFs very much!
Hi,Sinatra:
My main job is to design transistor, after that I should design the matching circuit to mearsure the transistor and make datasheet! Before, I am a PA designer. So plz give me some advice, Thank you!
I think LDMOS will be dead in a few years due to GaN. Of course allot of the skills learned in tranistor design can be applied to several processes. Check here for company ratings:
Hello Zltogo.
The oportunity you have is not to be missed. Mainly if you are still young (as I believe).
The LDMOS transistors are the best now for high power applications.
Designing power amplifiers is always an important skill.
I don't expect that you will be developping matching structures in Freescale. I believe they surely have computer controlled power tunners. You can extract parameters and evaluate the performance of any transistor just using those tuners. They are expensive but I believe they should have them.
If they don't have them it is even better for you, that you will really have to find a way to design the matching structures. And test the transistors.
There is also some trend to increase the drain voltage to over 50V to get more power and reduce the drain current (increase reliability). I think the LDMOS will not die. they will be aroung for long time.
The experience you will get is worth trying. Let's hope you will be working with some of those old great Motorola guys.
LDMOS will be dead in a few years? I think this is a joke.
I can bet that even BJT’s will be still alive 10 years from now.
I know that a lot of people hate them, but in my opinion Motorola (and derivates) had and still has the best RF engineers in the world. At least they are not getting lost around Smith chart
I'd say BJTs are dead now and have been for a while, at least for high power RF amps. Even for HF you can use VDMOS. Maybe they still make them for avionics where you need replacement parts for 20 years, but not much for new product development.
I think LDMOS will be where BJTs are today, pretty much just replacement parts.
GaN has advantages over LDMOS of:
High breakdown voltages (I have read of up too 300V).
Higher mobility like that of GaAs, where Si LDMOS putters out at 3 GHz.
Better reliablity since there is no gate oxide to punch through, also better immunity to ionizing radiation.
Now I'm sure GaN will cost more for a while, just as GaAs costs more today. However in volume use the price should come down.
If I were to get a job at a fab today, I'd go with GaN. I know Cree is hiring, and I think Nitronex too.
I know that a lot of people hate them, but in my opinion Motorola (and derivates) had and still has the best RF engineers in the world. At least they are not getting lost around Smith chart.
Never heard of anyone not likeing Motorola engineers, but the company, oh yes. They treated their engineers like crap once it shifted from a tech company to consumer electronics during the dotcom boom. Similar from HP to Agilent.
Maybe if you go for an interview try to escape the HR people and talk to the old timers to see what goes on behind the scenes. This should be done with any company.
Motorola always treated employees poorly. They were laid off at the slightest downturn in the company business volume. It may be even worse today from what some of the above posts say.
As far as what technology is alive or dead, you have to state the application. Linear Technology IC company is making money by the basket full from bipolar products.
Hi, Sinatra:
Thanks for your advice very much, You are so kind!
This RF design center will be in ChengDu of China, So I'm in China now. There is a big market for the coming 3G in China, But the standard of 3G will be TD-SCDMA in China, and there is no transistor for that standard.
As you said, I am young, I will take that job and wrok with older motolola guys.
Thank you!
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