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How to design a mixed signal IC?

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triquent

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mixed signal IC?

can we discuss something about mixed-signal IC? I was told that mixed signal ICs is the combination of digital ICs and Analog ICs on the same chip. So usually how to design the mixed-signal ICs in industry? :D
 

Re: mixed signal IC?

mixed signal usually when there is a mixture of digital and analog signals: for example a PLL has both square digital waves and sine waves, same with a data converter and so on. also a chip can have an analog section and a digital logic section, so they are mixed signals.
 

Re: mixed signal IC?

so mixed-signal circuits means a specfic kind of circuits. such as ADC, DAC or PLL as you named. When you design this kind of circuits, you are designing mixed signal circuits. But I found ADC or PLL are included in the analog circuits books.
also can you give an example about the chips that have an analog section and a digital section?
thanks.
Puppet1 said:
mixed signal usually when there is a mixture of digital and analog signals: for example a PLL has both square digital waves and sine waves, same with a data converter and so on. also a chip can have an analog section and a digital logic section, so they are mixed signals.
Click to expand...
 

mixed signal IC?

i think mixed IC is the future,for it use the both of digital & ananlog.
 

Re: mixed signal IC?

Noise isolation is important issue in mixed-mode chip. You have to face boundary and pin arrangement problems. ESD design is a big challenge as well.
 

mixed signal IC?

Interface circuits such as USB PHY, IEEE-1394, DVI, and LVDS are good examples of mixed-mode signal ICs.

If SOC is the future, mixed-mode signal will be the key.
 

Re: mixed signal IC?

PLL is a mixed signal IC, since you can argue that an LC VCO is an analog circuit, the divider in the PLL is digital, the charge pump is analog, and the phase detector is digital.

also the signals are analog and also digital through the PLL, since some are square, some are sinusoidal.

for example most circuits using a square waves, are are switching would be digital, while one that is amplifying would be analog.

does that make it more clear to you now ?
 

Re: mixed signal IC?

i'm working on mixed-signal SoC.

Challenges actually lay on fab. but not design.

An Intel manager have claimed that SoC is dead meat for the high cost, while TI try all they can to fight back.
 

mixed signal IC?

Intel have little experence in analog ic,so if Ti want to win intel in the digital consume area, the mixed-signal IC is a very important thing to fight with Intel.
 

Re: mixed signal IC?

SOC is tendency in IC design field.
 

Re: mixed signal IC?

Hi

The challenge is in layout...you have very carefull when placing the block especially sensitive analog blocks ( VCO ) .....
 

Re: mixed signal IC?

I don't know much except that the mixed signal designers are on high demand in this (kind of) sluggish hi-tech semi industry.
 

Re: mixed signal IC?

Hi, I can't really realize why ESD deisgn also play an
critical role in mixed signal design?
 

Re: mixed signal IC?

Rather than pure analog or digital design, circuit designer and layout designer will find much more difficulties in mixed -signal design.
 

Re: mixed signal IC?

anyone can talk about the procedure of desinging mixed_signal circuits.
ex. all of mixed-signal IC is designed as full customer circuits? or digital part will be designed as the ASIC, using a lot of tools.
 

Re: mixed signal IC?

my experience about mixed mode IC is a power speech chip, it consists of DAC12bit, rc osc, lvr, rom, ram, 8/4 bits MCU.....etc.
schematic tool: all built up with workview (schematic entry tool)
digital simulation tool: modelsim or nc-verilog (analog parts use verilog model)
analog simulation tool:hspice
debuging tool: Debussy
 

Re: mixed signal IC?

The general oppinion is that SoC is kinda stupid and a simple buzz word. It is really dificult and expensive sometimes to combine certain blocks. Only try to put high speed digital with some decent accuracy ADC, and by high speed digital I dont mean a pentium iV, but only some simple buffers. Bye bye adc. Si is expensive and area disappaers in guard rings and noise decoupling.
So, is impossible to say at this momment that Soc is the future. You can definitely put on the same chip sometimes digital and analog, but for the rest of the time I thnk smart packaging is a much better idea.
 

mixed signal IC?

can anybody introduce the ESD in mixed-signal design ,especially in adc design?
thx
 

Re: mixed signal IC?

i don't know about ADC ESD protection but check out this:

**broken link removed**

Added after 2 minutes:

about SOC

there are two different drivers:

academia wants to integrate and make everything single chip because professors like to make new advances and integration makes them famous -- look at the single chip cmos radio -- this has been going on for years....

now industry is now doing system in a package -- for mixed rf, analog and digital SOC doesn't make sense, is more expensive ...
 

Re: mixed signal IC?

Exactly whap puppet said. Academia has time and they want something new and exciting at any price. They have also very good expertise, the best maybe. They can play with things, failure is not a problem, this is how science works.
On the other hand industry has 2 main problems: money and time to market. Moreover, not all the companies out there have excellent analog designers. They want to do it fast, first of all, and cheap (cheap and fast come toghether most of the times, becuase the cost of design is large). They can't afford to spend 5 years like PhD students optimizing a single circuit.
 

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