# VLSI Questions and Answers – Scaling Factors -2

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This set of VLSI Interview Questions and Answers for freshers focuses on “Scaling Factors -2”.

1. Carrier density is scaled by
a) α
b) β
c) 1
d) α2

Explanation: Carrier density in channel Qon is scaled by 1. Carrier density is given by C0*Vgs where C0 is scaled by β and Vgs is scaled by 1/β.

2. Channel resistance Ron is scaled by
a) α
b) β
c) 1
d) α2

Explanation: Channel resistance Ron is scaled by 1. Channel resistance is given by (L/W)*(1/Qonµ).

3. Gate delay is given by
a) Ron/Cg
b) Ron * Cg
c) Cg/Ron
d) Cg2 /Ron

Explanation: Gate delay Td is given as the product of Ron, channel resistance and Cg the gate capacitance.

4. Maximum operating frequency is scaled by
a) α/β
b) β/α
c) α2
d) β2

Explanation: Maximum operating frequency f0 is scaled by α2/β. This is given by (W/L)*(µ*C0*Vdd/Cg).

5. Saturation current is scaled by
a) α
b) β
c) 1/α
d) 1/β

Explanation: Saturation current Idss is scaled by 1/β. This is given by (Co*µ/2)*W/L*(Vgs-Vt)2 .

6. Vgs is scaled by
a) α
b) β
c) 1/α
d) 1/β

Explanation: Gate to source voltage Vgs is scaled by 1/β. All voltages are scaled by 1/β.

7. Current density J is scaled by
a) α/β
b) β/α
c) α2
d) β2

Explanation: Current density J is scaled by α^2/β. Current density is given by Idss/A where Idss is scaled by 1/β and area A by 1/α^2.

8. Power dissipation per gate is scaled by
a) 1/α
b) 1/β
c) 1/α2
d) 1/β2

Explanation: Power dissipation per gate is scaled by 1/β^2. This is the sum of static component Pgs and dynamic component Pgd.

9. Power dissipation per unit area is scaled by
a) 1/α
b) 1/β
c) β22
d) α22

Explanation: Power dissipation per unit area Pa is scaled by α22. This is given by Pg/Ag where Pg is scaled by 1/β2 and Ag by 1/α2.

10. In constant voltage model, the saturation current is scaled by
a) α
b) β
c) 1
d) β2

Explanation: Saturation current is scaled by 1 in constant voltage model. This is because saturation current is scaled by 1/β and here in constant voltage model β is 1.

11. In constant field model, maximum operationg frequency is scaled by
a) α
b) β
c) α2
d) β2

Explanation: In constant field model, maximum operating frequency is scaled by α. Maximum operating frequency is scaled by α2/β and here in this model β = α.

12. In constant electric field model, power dissipation per unit area is scaled by
a) α
b) β
c) 1
d) β2

Explanation: Power dissipation per unit area is scaled by 1 in constant electric field model. This is scaled by α22 and here in constant electric field model β = α.

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