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Hey,patriot!
It's also can be explained from the view of large signal point. The gate voltage of M3 forces the drain current of M4 to increase, but the current of M2 decreases. In other words, M4 has to sink identical low current with M2 while keep identical high |vgs| with M3. So, |vds| of M4...
Bandgap Reference
I agree with jnuhope.
Generally, opamp is biased by current not voltage, to get a constant Gm. So you need to design a current source independent with temperature and power supply.
What do you want to bias by voltage reference? The gate of current source MOS?
Thank you everyone!
I also think it is to limit peak current. In fact, this chip has no requirement in speed, and it needs delay intendedly. But power is important for it. So I think it is for geting low-power by sacrificing speed.
I also need other advice!
There are the papers about bgr psr analysis, but i think they're not detailed enough, and i don't understand how to calculate them. My questions are mainly about dc psr, not including frequence part.
Wish you give me a easy explain.
Thank you!
The two kind bgr circuits and dc psr solutions are shown below. They were refered from papers, but I don't know how to calculate (There were no detailed deduction process in papers). I have no textbooks such as Gray, Allen, Razavi, Baker's books refering to topics about bgr psr calculation (most...
explain current sources
The circuit is shown in Fig 1. as you can see, this is a inverter, but I don't know why M3 is used in here. Obviously, M3 is a current source. Is it for biasing the inverter?
The circuit is a basic unit of a chip. In that chip a lot of digital circuits, such as AND, OR...
ro from model
walker5678, I agree with your point. I think the way of geting lambda is to run a single MOS Ids-Vds simulation sweeping different L value, and get different lambda for each L value.
lambda + bsim model
I've found methods in Allen's book to exact parameters such as Lambda, K', gamma for hand caculation from Ids-Vds curves. Does anyone use this way to get parameters for first step design?
Hello, evilguy, I have a question that whether PCLM in BSIM3v3 can be used to...
Thanks so much for your advice! I'm a beginner and inexperienced. In the textbooks authors said that the first design step was to do hand calculation before computer simulation. So I always try to do hand calcution, and I think it's a good way to obtain design intuition. I'm using XFAB 0.6u...
weak inversion id0
I'm designing low power circuits,the current each branch is about several decad or hundred nA. i think it can be generated by biasing MOS in weak inversion region. The simplified formula in weak inversion region is as follows: id=(w/l)*Id0*exp{vgs/[n*(kt/q)]}, so if know...
bsim3v3 model parameters cox
Is this the way of caculating?
get gds and id from operating point analysis, and lamda=gds/id?
but i found the value of lamda is still large variable for different vgs and w/l. maybe it's true that lamda is useless for BSIM3v3. So do you have better method to...
bsim3v3 model parameters
Hello everyone! I am a beginner of analog IC design, and I have some questions about how to use BSIM3v3 model parameters to design by hand. From BSIM3v3 model parameter UO, VTHO, TOX can be found, and COX can be get by COX=εOX/TOX, but lambda is unknown. Someone has...
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