exam_pastc

# Exam_pastc - 2 3.5V V D V S R D V DD I DS 8V Given V T =1V K = 0.25mA/V 2 2k Ω Find V DS and I DS for V G = 3.5V MOS is in saturation mode mA m V

This preview shows pages 1–4. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 2 3.5V V D V S R D V DD I DS 8V Given V T =1V K = 0.25mA/V 2 2k Ω Find V DS and I DS for V G = 3.5V MOS is in saturation mode mA m V V K I T GS DS 5625 . 1 ) 1 5 . 3 ( 25 . ) ( 2 2 = − = − = V k m R I V V D DS DD DS 875 . 4 2 ) 5625 . 1 ( 8 ≅ − = − = mA k I DS 5625 . 1 2 875 . 4 8 = − = ∴ 4 (18) Given V T = 1V K = 0.25mA/V 2 1 = ∴ I R 1 V 1 I1 8V V 2 V 3 6k Ω 12k Ω R 2 4. (a) If V 2 = 0.5V, find I 1 and V 3 . (b) If V 2 = 2V, find I 1 and V 3 . State clearly the reasons for your answer. Given V T = 1V, K = 0.25mA/V 2 . Given that at triode region, I DS = 2K[(V GS - V T )V DS –V DS 2 / 2] at saturation region, I DS = K[(V GS - V T ) 2 ] (19). (19) If V 2 = 0.5V a V V 8 3 = ∴ If V 2 = 3V b mA m V V K I T GS 1 ) 1 3 ( 25 . ) ( 2 2 1 = − = − = ∴ V k m R I V 2 ) 6 ( 1 8 8 1 1 3 = − = − = ∴ NMOS is saturated since 1. 3 > 1 2. 2 = 3 - 1 Assume NMOS is in saturation NMOS is saturated since 1. V GS > V T 2. V DS = V GS- V T V GS < V T NMOS cut off 0.5 < 1 R 1 V 1 I1 8V V 2 V 3 6k Ω 12k Ω R 2 (26) hence V O = 3 + 1 = 4V V DS = 12 V = V DD is impossible since MOS is not cut off (V DGS > V T ) Vi V O R D V DD I D 13V 2k Ω 9V 3V 2k Ω 5 (26) Given V T = 1V K = 0.5mA/V 2 NMOS is in triode since 1. V GS > V T 2. V DS < V GS- V T NMOS is triode since 1. 6 > 1 2. 1 < 6 - 1 V or V V V V V V V V V m k V V V m V V V V K k V R V V I DS DS DS DS DS DS DS DS DS DS DS DS DS T GS DS D DS DD D 1 10 10 11 ] 2 5 [ 2 10 ] 2 5 [ 1 2 10 )] 2 ) 1 2 8 [( 1 ] 2 ) [( 2 2 10 2 2 2 2 2 = ∴ = + − ∴ − = − ∴ − = − ∴ − − − = − − = −...
View Full Document

## This note was uploaded on 10/28/2011 for the course ELEC 101 taught by Professor Chan during the Spring '09 term at HKUST.

### Page1 / 12

Exam_pastc - 2 3.5V V D V S R D V DD I DS 8V Given V T =1V K = 0.25mA/V 2 2k Ω Find V DS and I DS for V G = 3.5V MOS is in saturation mode mA m V

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online