Electrical Engineer Interview Questions

What types of CMOS memories have you designed? What were their size? Speed? Configuration Process technology?





 
What work have you done on full chip Clock and Power distribution? What process technology and budgets were used?

What types of I/O have you designed? What were their size? Speed? Configuration? Voltage requirements? Process technology?

What package was used and how did you model the package/system? What parasitic effects were considered?

What types of high speed CMOS circuits have you designed?

What transistor level design tools are you proficient with? What types of designs were they used on?

What products have you designed which have entered high volume production?

What was your role in the silicon evaluation/product ramp? What tools did you use?

If not into production, how far did you follow the design and why did not you see it into production?
        
We have a portable device that operates with 12 volts of direct current.

We currently use 8 AA 1.5 volt batteries to generate the 12 volts. However, the 8 AA batteries add too much weight to the device.

Is it possible to substitute the 8 AA batteries with one 9 volt and two AA to create the 12 volts?

Or, can we utilize two 9 volt batteries with a converter to create 12 volts of direct current?

Our objective is to reduce the amount of batteries required, thus reducing the weight. Can you please assist me.

Use two 9 V battery and build a simple resistive voltage divider.

The setup is 18 V from the two 9 V batteries connected in series and in series with 2 resistor R1 and R2. The desired output voltage 12 V will be taken between the 2 series resistors R1 and R2.

The formula is Vout=[R2/(R1+R2)]xVin. Or you can first get the ratio [R2/(R1+R2)] that when multiplied with 18 V will result 12 V. Then the resistance value can be computed.
    
While Vince’s suggestion above would work to make 12V there is a series flaw.

If you have a load on the 12V (which of course you do) then you will draw current through R1.

Thinking about that, you are going to drop your voltage due to power dissipation in the resistor. Besides, the resistors are always consuming power in this situation so it is not such a good idea in the first place.The 9V + 2x 1.5V battery idea works but is still kinda clunky.

Is there more information on the design, ie. Current requirements, battery life expectation, etc. If so, then we can look into a more efficient design.