High speed board design interview questions

1. when board trace starts radiating, Hint:In relation with wavelenth 2. Propagation delay is more in which topology (stipline or microstrip) 3. How to decide layer stack up 4. What is significance of dielectric constant 5. When you call signal as high speed signals: Hint: do not give silly answers such as greater than 100MHz 6. what is the difference between FPGA and ASIC 7. What is CLB and its significance in FPGA 8. What is SSTL and its advantages 9 When to use terminations, Series termination when? and parallel termination when? 10. Disadvantage of each termination 11. Propagation delay of 1 inch PCB trace on micro strip 12. What is buried via 13. Draw the near end cross talk shape 14. what is far end cross talk and near end cross talk: Hint: See black magic for good explanation 15.What is the bandwidth of a signal 16. if you increase width and height of transmission line what is effect on charcterstic impedence (Zo) 17. If we measure a cable impedance(Z0=50 ohm) using multimeter what is impedence 18. what is the min bandwidth of oscilloscope required to measure 100MHz signal. 19.what is skin effect 20.Input impedance of short grounded PCB trace looks like 1.inductive 2.Capacitive 3.Resistive Ans:Inductive 21.what is ISI 22. Write Setup and hold equations for Source synchronous memory 23. Impact of Frequency on on hold time 24. what is great advance of differnetial signalling 25. Why eye diagram used for evaluation of high speed signals 26. What is bath tub curve 27. what is jitter? its types 28. SATA speeds. 29. HDMI speeds 30. HDMI resolutions 31. USB charterstic impedence 32. How USB determines a slave is connected. 33. DDR3 vs DDR2 ( what as hardware board engineer must know) Routing topology has chaged, RESET pin introduced. 34.what are advantages of CML(current mode logic) 35.How to measure reflections using TDR 36.what are dielectic losses 37. what is CL in DDR 38. How DDR3 speed has been incresed when compared to DDR4 Hint: Pre-Fetch technology is different. 39. what is eye specifications 40. What is significane of equalizer 41. can pre-emphasis and equlaiser be used at same time 42. what is insertion losses 43. what is ground bounce 44. how many number of decoupling capacitors you place around an ASIC, hint: I=C*dV/dT 45. what is Vcc sag. 46. Explain how you decrese power consumption if you decrease core voltage 47. what is significance of 2D field solver. 48.common mode noise tolerance for LVDS signalling 49.NEXT near end crosstalk grows at what dB/Decade 50.what is S12 signifies

hardware Interview questions

Hardware Board design Interview questions 1. How do you select following 1. Freewheeling diode purpose selection 2. Micro controller Crystal accuracy 3. Crystal load capacitance 4. R, L, C, FET and BJT selection 2. How do you limit surge voltage and inrush current? 3. How do you choose Instrumentation amplifier? 4. Design considerations for Instrument amplifier? 5. Relation between CMRR and frequency? 6. Design square wave generator using inverters/opamp 7. Power dissipations in LDO and switching regulators 8. How do you interface analog sensor to controller? 9. What is pinch off voltage? 10. What are the ADC errors and how to minimize? 11. What are accuracy, resolution and precision? 12. Decupling capacitors use? How to choose the required decoupling capacitance value for a given controller/PLD 13. Differences between EEPROM and FLASH 14. What will happen if the two trace lengths of differential signals are not same? 15. Draw voltage double circuit 16. Draw charge pump circuit 17. Draw an op-amp based circuit to obtain 0-3V from +/-10V input 18. Important parameters to select op-amp 19. What is virtual GND how it is happening in op-amp? 20. Current mirror circuit and explain 21. I2c timing diagram 22. Flash/SRAM Read timing diagram 23. What is clock stretching? 24. Why do we use pull-ups on I2C bus and how to calculate resistance values? 25. What is noise margin? 26. What is IB, Beta and IC relation for saturated BJT? 27. What is the maximum phase shift you get with capacitor/RC ckt ? 28. Draw BJT amplifier ckt with equations and Output characteristics 29. Draw Schmitt rigger ckt with equations 30. How do you protect circuit from reverse polarity? 31. Differences between RS232 and RS485 communication 32. What is MultiMaster Communication? 33. Frequency response of RC LPF with equations 34. What type of simulations you have done in PSPICE? 35. Compare BJT and FET 36. Draw constant current amplifier using BJT 37. What are the error sources for op-amp? 38. What is slew rate and unity gain bandwidth? 39. How do you select controller for typical application 40. How do you interface 7segment LED’s with controller 41.Serial communications SPI, I2C, RS232,RS485 and RS422 42. Draw BJT amplifier and Derive Gain formula Continental 1. CLK oscillator design using Inverter 2. Inverting and non inverting amplifier design 3. Protection circuits for Surge and inrush current 4. Controller selection 5. Block diagram Power consumption of your board 6. In I2C communication which side (Device or master) is open collector? Honeywell Bangalore: 1. How the isolating amplifier provides impedance matching 2. Instrumentation amplifier practical design considerations 3. EMI/EMC standards 4. Flash and EEPROM differences 5. Differences between LDO and STD LDO 6. Constant current amplifier design 7. How the virtual gnd will happen in opamp 8. OPamp internal diagram 9. Current mirror circuit with equations 10. CMRR and PSRR relation with frequency? 11. How do you select instrument amplifier and advantages of Instrument amp 12. Which source is best for far communication I souce or V source ? and how? 13. Types of simulations in SPICE 14. MTBF and Error budjet calculations 15. ADC types and operations 16. Schmittriger ckt with equations 17. ADC error types and how do we minimize 18. Under/over sampling advantages and disadvantages 19. Aliasing effect in an ADC 1. boost regulator operation 2. +ve and –ve amplifier design using opamp 3. BJT amplifier gain calculations 4. BJT and fet differences 5. how do we select an ADc for 10V i/p with noise environment 6. How will you measure 50V on a board by ADC, Hint: Do not use resistor divider,it loads supply. use a differential amplifier 7. Battery present indication using opamp like how it glows in LAPtop 8. Use of RE resistor in BJT amp 9. BJT amplifier design 10. how do you control ADC errors 11. RC LPF design calculations and frequency response with angle calculations 12. RS232 communication protections 13. Difference between normal diode and surge protection diode 14. Impulse , step ramp equations and if we give thse to RC lpf wht will be the output? Goodrich: 1. Design an Half wave rectifier 2. How do you select frequency of operation in buck regulator 3. what is the significance of schottkey diode in buck regulator, advantages over normal diode 4. L&T: 1. Design a opamp ckt to convert +/-10V to 0-3V 2. buck regulator function 3. optical isolator selection GE: