What should I learn to migrate from CMOS to bipolar?

hi all,

I am going to migrate from CMOS to bipolar design, what are the topics should i study or things should i know?

Surianova

Re: from CMOS to bipolar

surianova said:

hi all,

I am going to migrate from CMOS to bipolar design, what are the topics should i study or things should i know?

Surianova

Click to expand...

sorry that I am not helping you..
Still, I am very curious that why you will switch from CMOS to BJT?

Scottie

Re: from CMOS to bipolar

scottieman said:

surianova said:

hi all,

I am going to migrate from CMOS to bipolar design, what are the topics should i study or things should i know?

Surianova

Click to expand...

sorry that I am not helping you..
Still, I am very curious that why you will switch from CMOS to BJT?

Scottie

Click to expand...

For higher speed in GHZ range, u need to be in bipolar or Sige process,Cmos
cannot go that high speed.

from CMOS to bipolar

yes, rf about biplor is a good topics.
another is low cost ic, such as 431.
you can study from bicmos, too

Re: from CMOS to bipolar

surianova,

I am going to migrate from CMOS to bipolar design, what are the topics should i study or things should i know?

Click to expand...

From CMOS to Bipolar technology, you are refering to Process or Circuit? Which kind of Bipolar, BJT or HBT?

scottieman,

Still, I am very curious that why you will switch from CMOS to BJT?

Click to expand...

Bipolar (HBT) can operate at higher frequencies than CMOS, although at the expense of higher power consumption.


surianova,

Saw you later post, I presume you mean transistor circuit level.
You should know:
1. DC Biasing, Circuit Gain Configuration, Parasitics, Feedback and Stability in Bipolar.
2. Larger Leakage Current and Shot Noise in Bipolar.
3. In RFIC, impedance matching to a Bipolar is different from MOS. Bipolar is easier to match, in fact.
4. Bipolar has a better linearity than MOS (BJT vs MOS), in most cases, although some MOS are better (HEMT vs HBT) but HBT is faster than HEMT.
5. Need to emphasise on noises in Bipolar. Bipolar is notorious for being very noisy.

Re: from CMOS to bipolar

thanks for the answer. By the way, any homepage can i refer to, to get
more infomartion?

Re: from CMOS to bipolar

I had this problem in the past.

GHz Microwave and RFIC designs in Bipolar are not readily available in books. IEEE(USA) and IEE(UK) journals are the best sources.

Few microwave books like "Microwave Transistor Amplifiers: Analysis and Design" by Guillermo Gonzalez. But this doesn' touch much on HBT Amplifier.

Bipolar for RF are usually very old books, refering to BJTs.
More books on CMOS RFIC designs, not surprised.

I still recommend journals.

Re: from CMOS to bipolar

Bipolar is only device ... the design tech. will be remain the same .. u need know how biasing n some trade off ... only part is diff.. laid them out not easy task... expecially for higher speed......

Re: from CMOS to bipolar

Hi Surianova,

Migrating from CMOS to Bipolar is a good choice especially when you are about to design a high frequency circuits. Even in CMOS we can achieve to design for 10Gbps but with the help of On chip inductor where it is not a good choice for designers when it comes to chip size. I think that in order for you to understand about Bipolar design, it wont be a big problem because all the method of biasing and operating a transistor will be the same concept as in CMOS, only thing will be different is in the sizing of transistors coz the amount of current follows is determined by the area size of emitter and also in biploar we have to consider more on the β (current gain factor) that involve base compared to CMOS in the gain determination an so on and also understand the process as well before start to design.

As a starter you can refer books like Sedra & Smith, Paul Gray Meyer, Laker & Sansen which are covered more on Bipolar design.


Cheers,
Suria

Re: from CMOS to bipolar

Hi SkyHigh

[/quote]
Bipolar (HBT) can operate at higher frequencies than CMOS, although at the expense of higher power consumption.
[/quote]

I have a question about this, if we would like operate cmos and bjt in the same
frequency, 1GHz for example, which one consumes more power? bjt should
consume less power, right?


[/quote]
Saw you later post, I presume you mean transistor circuit level.
You should know:
1. DC Biasing, Circuit Gain Configuration, Parasitics, Feedback and Stability in Bipolar.
2. Larger Leakage Current and Shot Noise in Bipolar.
3. In RFIC, impedance matching to a Bipolar is different from MOS. Bipolar is easier to match, in fact.
4. Bipolar has a better linearity than MOS (BJT vs MOS), in most cases, although some MOS are better (HEMT vs HBT) but HBT is faster than HEMT.
5. Need to emphasise on noises in Bipolar. Bipolar is notorious for being very noisy.[/quote]

For 4. Do you mean bipolar has better linearity is because of additional feedback
resistor? For crude bipolar, it should be worse linearity than cmos due to the junction
law.

Re: from CMOS to bipolar

i think there is no method to can be easy to migrate cmos to bipolar . i think if the circuit migrate should based on the comprehension of the original circuit .based on the original circuit comprehended ,we can redesign the circuit on the new technology .