Sometime back i interviewed for a position at a big MNC. I would like
to share my interview with you so that you can know the questions that
interviewer ask these days. Position i was looking for was a Backend
Design Engineer (logic syn, PV etc).
Here are some question which i remember.
1.) Optimize 2 input inverting mux (D1 connected to A, D2 tied low and
Select tied to B)
2.) Solve the following using Boolean logic.
a. O = A + B[(AB+B) + AB’]
3.) Draw circuit for the following logic.
If tag{3:0} == adr(3:0)
Then (
Match = 1
)
Else
(
Match = 0
)
End
4.) What is setup and hold and what factors determine setup and
holdtime calculation for a flop.
5.) What is PV and how does it impact the timing of a chip
6.) What happens to power if voltage drops. Tell me the equation of
static and dyn power.
7.) What is noise and RV and how to fix it
8.) What is spacing and shielding and when to prefer either of two.
9.) What determines the metal pitches for a particular process
technology.
there were more however do not remember now.
will post more once it comes to mind.
The part after STA, FV, CTS would be ASIC Place/ Route.
Few companies would hire specifically for ASIC Place/ Route work.
So, Students should concentrate more on Front-end design part of ASIC
Design. [HDL, testbenches and after some experience students get an
opportunity to do logic synthesis, STA, FV and other front-end tasks.
I think, more new-college-grads are chosen for Front-end design part
of ASIC Design than Back-end.
Once again, dont worry too much about all steps in detail [as a new
college grad]
Remember concepts are important; rattling off specific tool commands
may NOT show your understanding of the tool.
For example,
1] What are various compile strategies?
Which strategy should be used when?
think of all the variables involved, top-down, bottom-up, small-
design, large-design, constraints already defined, tight constraints,
loose constraints, is it a new design OR migration from earlier
design?
I can understand you may NOT be able to think of all the variables
BUT the key here is to "let the interviewer know HOW YOU THINK"
Remember that the interview questions are generic concentrating on
fundamentals.
always ask the questions like why and how that phenomenon happens. If
the phenomenon is happening some particular way, [may be the way you
do NOT want it to happen, then see how to improve that thing ; So,
first you will have to think why it is happening that way and is there
a better way to do it]
Targeting above sentence to VLSI point of view; THINK OF all VLSI
Qns with that approach; area/ speed tradeoff, WHY does textbook say
that critical input should be connected closer to output, 2bit-line
SRAM versus 1 bit-line SRAM tradeoff.
If you can explain it clearly to yourself, any interview will be piece
of cake.
