Written Test Question for Physical Design Engineer: Question Set – 6



 Code: ALTRN0Y112020PD


Some companies take a written test sometimes to shortlist the candidates before the interview process. This is a common process if the applicants are large in numbers. In such written test, the format is MCQ and some short questions. 

We are very thankful to one of our follower who has appeared in this test and shared these questions based on memory. The purpose of sharing this question is only to provide the right guidance to the candidate who is going to appear in such a written test. I would encourage all the freshers to practice these question for their future test/Interview. I would also encourage to find the answer to these question either by own. There is no sense of proving the answer to these questions here. But if someone finds any question really difficult to solve and open discussion in the comment section. 


1. Hold slack equation 

2. Setup slack equation
3. When did hold analysis depends on the frequency of the clock 
a) half cycle path
b) single cycle path 
C) multicycle path 
d) it never depends 
4. While doing OCV which things are considered for setup analysis 
a) max launch path delay and min capture path delay
b) min launch path delay and max capture path delay 
c) max launch and capture path delay
d) min launch and capture path delay 
5. How to fix EM effect 
a) decreasing the space between metal layers 
b) decreasing straps 
c) increasing drive strength of the driver 
d) increasing space between metal layers 


6. Why do we add tap cells 
a) to maintain well continuity 
b) to prevent latch up  
c) to prevent DRC’s 
d) all of the above 
7. Why do we add metal fillers 
a) to ensure etching properly 
b) to ensure density issues 
c) to increase the area of the chip 
d)to ensure well continuity 
8. If the schematic has 11 and layout is 10 nets then, what might be reason 
a) opens 
b) shorts
c) ERC
d) all of the above 
9. Numerical problem related to finding clock frequency 
10. Numerical problem related to finding slack 
11. High positive skew leads to
a) setup violation 
b) hold violation 
c) DRcs
d) all of the above 
12. In VLSI Design, CMP stands for? 
13. Numerical problem to find setup slack 
14. Nand and Nor gate logic diagram SOP forms
15. Setup uncertainty increases from placement to CTs
a) true 
b) false
c) based on SDC 
d) based on clock frequency 
16. Only clearing LVS leads to the proper functioning of the chip 
a) true 
b) false 
17. Numerical problem related to reg to reg data path delay calculation 
18. A CMOS circuit consumes only a significant amount of power during 
a) static state 
b) when cooling 
c) when warming
d) all of the above 
19. Routing congestion depends on which factors
a) ratio of required layers and available layers 
b) ratio of available and required 
c) depending on availability of metalayers 
d) none of the above 
20. Question related to ground bounce, power bounce and glitch 


21. Value of threshold voltage depends on
a) doping concentration 
b)distance between source and drain 
c) temperature 
d) all of the above 
22. Why we reorder scan chains during placement stage?
23. For multi-voltage blocks which power cells are used 
a) isolation cells
b) retention cells 
c) level shifters 
d) all
24. Which configuration is more preferable for floorplan 
a) double BACK  + channel width spacing 
b) without double back + channel width spacing 
c) double back + row alignment
d) none of the above 
25. Concept of fixing time violations by adjusting clock arrival times at the registers in the preCTS stage is called 
a) time borrowing 
b) managing skew 
c) maintaining timing 
d) none of the above 
26. While calculating standard cell utilization what are all will be considered 
a) macro + blockage + standard cell (area)
b) macro + blockage (area)
c) macro + physical cells + standard cells (area)
d) all of the above 
27. RV checks Are needed for 
28. Inputs for LVS
a) spice + netlist + rule deck
b) spice + rule deck + lib files 
c) OASIS + netlist + lib 
d) none of the above 
29. Via3 will connect which of the following metal layers 
a) 1 and 3
b) 2 and 3
c) 3 and 4
d) none 


30.  A 4-bit modulo 16 ripple counter uses JK flip-flops. If the propagation delay of each FF is 50 ns. The max. clock frequency that can be used is equal to


31. A pulse has a period of 15 ms. Its frequency is
32. A 8-bit successive approximation ADC has a full-scale reading of 2.55 volts and its conversion time for an analog input of 1 volt is 20 µs. The conversion time for a 2 volts input will be?
33 . How many binary numbers are required to represent a decimal number 748?
 34. DRC is used to 
a)to ensure chip fabrication
b)to ensure chip doesn’t get heated 
c)to verify parasitics on chip
d) all of these 
35.  Antenna diodes are used for 
a) to protect the gate 
b) protect VDD and VSS
c) to protect the substrate 
d) all of the above
36.  Buffers are added to 
a) to fix timing violations 
b) to fix DRC
c) to fix parasitic values 
d) all 
37. Metal pitch and metal spacing are the same 
38. What is the effect of high drive strength buffer when added in the long net 
a) delay of net decreases
b) delay of net increases 
c) delay doesn’t effect 
d) none of the above 
39. Cross talk glitch leads to 
a)timing failure 
b) functional failure 
c) substrate failure 
d)all of these 
40. Programmable special cells used during ECO
a) gate array filler cells
b) filler cells

c) metal fills 
d)decap cells 
41. What is a physical cell?
a) cell which doesn’t have any functionality 
b)  cell is not synthesized 
c) cell which is inserted only in layout 
d) all of the above 
42. Power gating technique in low power is used to reduce 
a)static power 
b)leakage power 
c)internal power 
d) all of the above 
43. Which of the following is not present in SDC 
a) max cap
b) max trans 
c) max current density 
d) max fanout 
44. The phenomenon associated with transistor switching when the gate voltage may appear less than the local ground potential 
a) ground bounce 
b) supply bounce
c) glitch 
D) none 
45. Leakage recovery can be achieved through 
a)Hvt to Svt
b) Lvt to Hvt
C)Rvt to Lvt.
d) svt to lvt
46. Which of the following must be fixed during physical design 
a) floating inputs 
b) floating outputs 
C) floating metals 
d) both b and c 
47. Which slew value will be propagated to slew _out of slew _A is 100 ps and slew_B is 80ps for hold analysis 
a) 80 ps
b) 100 ps
c) 20 pls
d) 180 ps
48. A 16-bit modulo 16 ripple counter uses JK flops if propagation delay is 25 ns, the max frequency of the clock is 
a) 25
b) 10
c) 2
d) 16
49. Digital signals transmitted on a single conductor must be transmitted in 
a) serial 
b) digital 
C) slow speed 
d) none 
50. In a certain digital waveform, the period is four times the pulse width, the duty cycle of the waveform will be? 
51. Follow pin connections to the standard s are done in encounter through
a)z- route 
c)trail route 
d) nano- route 
52.  set Y [ ]
        set Z [list a b c]
        lappend $Y $Z
What is the output 
a) empty list 
b) {a b}
c) {a b c}
d) none

[ Note: If you find any question has a typo error or is wrong, comment for the correction.]

 Thank you.


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