Validation Engineer Interview Questions in San Jose, CA | Glassdoor

# Validation Engineer Interview Questions in San Jose, CA

39

Validation engineer interview questions shared by candidates

## Top Interview Questions

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### Silicon Validation Engineer at NVIDIA was asked...

Aug 2, 2012
 For a 1GHz bandwidth oscilloscope, what will happen if you use it to monitor a 1GHZ square wave. If the Vpp of the square wave is 1V, what's the Vpp of the waveform shown on screen.6 AnswersA 1GHZ sine wave. If you know the Flourier transfer of the square wave you can answer this question easily.i have nothing to say your the best among the other companyIf you measure a 1Vpp 1GHz signal with a 1GHz bandwidth scope you will see a 700mVpp signal on scope's screen. Bandwidth is rated at 3db roll off point ;-)Show More ResponsesIt will show a sine wave. The oscilloscope bandwidth should be comparable to the rise and fall time of the square wave.Same question was asked to me.for a 1Vpp square wave, the amplitude of it's fundamental f0=1GHz component is 2/pi and assume the bandwidth given is 3dB bandwidth then you got half of it original amplitude at 1GHz which is 1/pi Vpp ~= 318mVppDue to bandwidth limit of scope, it will represent 1GHz square wave as 1GHz sine wave with a little higher than 1V p-p based on Fourier series. However, if bandwidth is just 1GHz, then roll-off effect comes in (70.7% of original signal), it might be 800-900mV.

### Validation Engineer at Marvell Semiconductor was asked...

Jul 14, 2010
 what is the cycle time of this circuit give 2 flops and some combi logic in between2 AnswersT>= t(c->q of 1st flop)+ t(delay) + t(setup of second flop) - delta(skew)Can you elaborate on what questions were asked in Phone interview?

### Hardware Validation Engineer at Super Micro Computer, Inc. (Supermicro) was asked...

Aug 31, 2011
 Skill test of schematic1 AnswerPin layout

### Memory Validation Engineer at NVIDIA was asked...

Jul 7, 2012
 Questions on reflection coefficients, return loss, insertion loss, return currents in PCB, EMI concerns, etc.1 AnswerFound in internet

### Validation Engineer at Super Micro Computer, Inc. (Supermicro) was asked...

Nov 19, 2013
 What are the differences between all of the Intel CPU architectures? The answer had to be provided in detail with specifications included.1 AnswerMultithreading, SMT, MOESI cache

### Hardware Validation Engineer at Super Micro Computer, Inc. (Supermicro) was asked...

Jul 20, 2011
 Tell me the waveform output at probe 1 and 2. The problem consist of a dc 5V going to a 5V sine wave input going to a capacitor. This system is then going into a 12V dc input with a two 1K resistor in parallel. This feeds into a emitter side of a transistor with a +-3V toggle as a base. The collector is going to ground. The two probe points is (1) before the cap and (2) before the emitter.1 AnswerThe solution was at probe (1) the waveform is a +-5V sine wave with a reference starting at +5V on the y-axis. At probe (2) the waveform has +-5V sine wave reference starting on +6V because the capacitor filtered out the initial +5V dc voltage and the two 1K resistor was a voltage divider on the 12V to make 6V.

### Memory Validation Engineer at NVIDIA was asked...

Aug 7, 2013
 How do you check PCIe Ref Clk?1 AnswerCPUID/GPU-Z

### Memory Validation Engineer at NVIDIA was asked...

Aug 7, 2013
 What happens if all harmonics are removed from a square wave? 1 Answerfundamental tone

### Memory Validation Engineer at NVIDIA was asked...

Aug 7, 2013
 Square Wave has a period of 1 GHz, Vpp = 1Volt, what will be the voltage displayed on the O-Scope with BW of 1 GHz1 AnswerOscilloscope bandwidth is the maximum frequency at which the signal gets attenuated by 3dB. So if you have a 1000mV signal with the same frequency as the BW of oscilloscope, measured signal will be 700mV.

### Validation Engineer at Google was asked...

Jun 17, 2012
 Google has 300 servers around the world. Servers are failing about 1 every month. How would you go about debugging the failure?? That's great, good answer. The failure is actually random. Nothing you've tried is able to duplicate the failure exactly the same. How do you approach this?? Another good answer. Now, what do you think is actually the cause of these failures?1 AnswerMemory Glitches.
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