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# ARM Interview Questions | MOSFET | CMOS 2021 The questions asked in the online test of the company ARM Holdings which is a VLSI semiconductor and software design company. They conduct online tests through hirepro. Data analysis, Problem-solving, and Puzzle questions were there in the aptitude section.

They focused mainly on MOSFET and CMOS technology. In that, they asked about CMOS circuits, MOSFET physics, and Digital electronics-related questions.

Here are the few memory-based questions of the ARM holdings company. Refer to these questions and excel in your preparation level for the online test of ARM holdings.

1. What is the transit time of the MOSFET, if it has a channel length of 180 nanometers and is Given Vds = 3V and un 750cm^2/V-sec?

Options

1. 144 fS
2. 155 fS
3. 166 fS
4. 133 fS

2. Five input NOR and NAND gates are designed with W/L width by the length of all the transistors are given by 10/1. What are the equivalent (W/L)n and (W/L)p of NAND and NOR gates respectively?

Options

1. 3/1 and 11/1
2. 4/1 and 20/1
3. 2/1 and 10/1
4. 5/1 and 9/1

3. For an enhancement type MOSFET, Given the current ID(on) = 325 mA and the gate to source voltage Vgs(on) = 12V. If the drain current ID for Vgs = 7V is 87.62 mA. What are the values of the proportionality constant K and threshold voltage Vth? Note: The Vth was observed to be less than 6V.

Options

1. K = 3 mA/V^2 and Vth = 1.6 V
2. K = 4.36 mA/V^2 and Vth = 5 V
3. K = 3.5 mA/V^2 and Vth = 2 V
4. K = 4 mA/V^2 and Vth = 2.5 V

4. How a depletion-mode NMOS can be turned OFF? Vg = gate voltage and Vth = the threshold voltage.

Options

1. By applying Vg greater than 0 V
2. By applying Vg less than Vth but Vg greater than 0 V
3. By applying Vg greater than Vth
4. By applying Vg less than -Vth

5. For an n-channel enhancement MOSFET, given u = u0, e = e0, the channel width W is 1 mm, the dielectric thickness is 1 nm, what is the value of the proportionality constant k? Note: u is mobility and e is epsilon(permeability).

Options

1. K = 5.56 mA/V^2
2. K = 11.12 mA/V^2
3. K = 23.41 mA/V^2
4. K = 17.28 mA/V^2

6. For the below circuit shown, if the input frequency is 4.35GHz. Find the output frequency. Options

1. 8.7 GHz
2. 4.35 GHz
3. 1.085 GHz
4. 2.175 GHz

7. A resistance equivalent model of the CMOS circuit is shown below. If R1 = 0.5 kOhm, R2 = 20kOhm, VSS = 5V, then what is the output voltage Vo for 0-state? Options

1. 4.88 V
2. 0 V
3. 0.122 V
4. 0.125 V

8. For CMOS circuits calculate the third-order input intercept point. If the transconductance gm is 30u and first-order and second-order gm is 1u and 0.5u respectively.

Options

1. 19 dB
2. 22 dB
3. 36 dB
4. 8 dB

9. To construct the source and drain of the nMOS, the substrate is doped with a carrier concentration of 10^18/cm^3. If the source and drain junction built-in potential is 0.72 V. Then calculate the depth of the junction depletion region.

Options

1. 30 um
2. 10 um
3. 50 um
4. 70 um

10. Calculate the value of the a.c. output voltage of the following amplifier by considering the Idss = 15 mA, Vin = 400 mV, and gm = 3.5 ms. Options

1. 703.2 mV
2. 806.4 mV
3. 600.9 mV
4. 905.3 mV

Below are the interview questions that are asked in an online test of Qualcomm. These are only memory-based questions, try to prepare these kinds of questions to clear the Qualcomm interview written test.

The written test will be of 60minutes, which consists of the aptitude section, the C programming section, and the technical electronic section. The given time won’t be sufficient to solve all the questions so solve very fast and with great accuracy.

The digital electronics section questions were as below

1. The circuit shown below is used as the Options

3. full subtractor
4. half subtractor

2. A dynamic RAM with a storage capacitance of C = 1uF which can hold a charge of 10uC is refreshed every 12.5msec. What is the discharge current and voltage of the capacitor?

Options

1. I = 0.8 mA current and V = 10 volts voltage
2. I = 1 mA current and V = 5 volts voltage
3. I = 1.25 mA current and V = 12 volts voltage
4. I = 1 mA current and V = 6 volts voltage

3. What is the SNR signal-to-noise ratio of a 16 bit ADC analog to the digital converter?

Options

1. 75
2. 86
3. 98
4. 67

4. Consider the boolean equation given below: F = ABCD’ + A’B’CD + AB’C’D + A’B’C’D’ . Write a minimum sum of products or min. SOP without don’t cares using Karnaugh map.

Options

1. A’B’ + A’B’C’D’ + CD
2. A’B’ + AB’C’D + ABCD’
3. A’B’ + AB’C’D’ + ABCD’
4. AB’ + A’B’C’D’ +CD

5. Find the next state output Qn+1 of the given circuit below.

Options

1. XQ’ + (X+Q)
2. X’Q’+XQ
3. X+Q
4. XQ

6. Find the output of the flipflop with input J and K. J = J1J2J3 and K = K1K2K3. Ans assume initially Q = 0.
J1 = 1011011
J2 = 0111010
J3 = 1111000
K1 = 0001110
K2 = 1101100
K3 = 1010101

Options

1. 0010110
2. 0011000
3. 0110110
4. 0110010

7. A modulo 50 counter can be implemented using

Options

1. 5 modulo 10 counters
2. 10 modulo 5 counters
3. 10 modulo 10 counters
4. modulo 10 counter followed by modulo 5 counter

8. Find the number of 8 to 1 multiplexers required to realize a 32 to 1 multiplexer.

Options

1. 4
2. 5
3. 6
4. 8

9. The instruction move AX, [CX] indicates which kind of addressing mode?

Options

10. Convert the following decimal value into the binary value (112)d = ( )2?

Options

1. (0000011)2
2. (0011011)2
3. (1110000)2
4. (0001100)2

11. Which one of the given options is the same as the NOT-AND gate?

Options

1. XNOR
2. NOR
3. NAND
4. NOT

12. Which one of the given options is the minimum number of AND gates required for the below-given logic function?

PZ + NZ

Options

1. 0
2. 1
3. 2
4. 3

13. Which one of the given options is the correct reduced expression for the below-given logic function?

(P + Y).(P’ + Y)

Options

1. 0
2. Y
3. P
4. P’ + Y

14. What will be the value produced if the number given below is left-shifted once?

11010011

Options

1. 10100110
2. 11100110
3. 10100111
4. 00110110

15. In 8086, If data stored in the AX register is 03H then what will be the content of the AX register after executing the following instructions.
`OR AX,09H`
`AND AX,AAH`
`XOR AX,FFH`
`NEG AX`
`NOT AX`

Options

1. FCH
2. F5H
3. F4H
4. 03HIf