IC designers need to know system?

[eejli]

how and in which extent does IC designer understand the system level thing? I am wondering. how sytem spec be partioned to each blocks.please give examples in the wireless communication applications.

Thanks.

 

[wjx197733]

I think somebody have not to understand system if he (she) design analog circuit. but must know system if design digital circuit

 

[SkyHigh]

You have to know system-level for many important reasons:
1. Power consumption
2. Noises
3. Speed
4. Robustness
5. Re-usability
6. Time-to-market
7. Cost
8. Manufacturability
9. Testability

It is not just digital alone. Analog and RF are just as important.

 

[eejli]

You are right. I just wondering if there is anybook talking about system level simulation. ADS can do some IIP3,GAIN,and noise figure system level simulation.But can I run an transient simulation on the system? If analog and digital ckts are put together,is the simulation possible?

Thanks.

 

[SkyHigh]

Yes, you can. I am surprised that you would ask.

OrCAD PSpice, Cadence HSPICE in Spectre/Virtuoso/Analog Design Environment, etc, all equipped with this basic functional capability to simulate transiences of mixed-signal analogue-digital circuits and systems, however only at one input frequency from a clock source or oscillator.

For RF and Microwave, you need to run at "stepped frequency" on Spice. Ansoft has this capability. The latest HP-ADS too, has this capability.

 

[eejli]

Thanks, Skyhigh,that would be great. Our company so far has only HSPICE and HSPICE RF available. It seems hspice RF does not support the mixed signal co-simulation. Anyway it is a tuff topic since not too much guys in company knows both analog/rf and digital design well.

 

[soccer]

i think if you are a front-end designer of digital system or a analog designer, you must have some background knownledge of system.

 

[omara007]

in my opinion, if we mean RTL Engineer by (IC Designer), then he may not need to understand the system itself .. most of the companies have Systems Departement different from RTL departement .. those System guys put all the system architecture and specs .. and then send the documents to the Principle engineer in the RTL team who breaks the specs into Hardware components and put a hardware description to the system ..
for example .. in communication systems .. you may design an FFT component without even knowing that it's FFT .. you maybe told to design some equations in RTL .. like the butterfly .. and those twiddle coefficients ..
But .. it's better to understand the system .. if this doesn't take from ur design time anyhow ..

 

[tony_taoyh]

I think it is better to know system for both analog and digital IC designer.

By the way, for the mixed signal simulation,
you can use:
Nanosim + VCS from Synopsys.
Or: Ultrasim + NC from Cadence.

Sysnopsys also support:
HSpice + VCS.. But is slow.


In the above simulator, you can use transistor level for analog portion, and use RTL or gate level for the digital portion.

Added after 6 minutes:

One SNUG paper for the usage of: Nanosim + VCS