Lecture30 2010 BiCMOSAmpsWithActiveLoads_1

Lecture30 2010 BiCMOSAmpsWithActiveLoads_1 - EE 311 Lecture...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
EE 311 Lecture 30 Friday March 26, 2010 6.7 in 4 th ed. BiCMOS Amplifiers Zubair Rehman
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 R in = 2( β+129 r e R in = infinity r e = V T / I E r π = ( β + 1)r e = infinity β = infinity A d = V o / V d = g m R C A d = V o / V d = g m R C g m ≈ 1 / r e = (I o /2) / V T g m = 2I D / (V GS - V T ) g m = I / (V GS - V T ) R IN FET >> R IN BJT but g m BJT > g m FET because V T < V GS - V T
Background image of page 2
3 BJT (FET) With Emitter (Source) Resistor R E (R S ) R out BJT = r o = V A /I C (0) R out FET = r o = (1/λ) / I D (0) Usually V A BJT > 2 x (1/ λ) FET BJTs have larger ROUT than FETs R out BJT = r o [1+g m (r π ||R E )] + r π ||R E BJT FET r π infinity R E R S R out FET = r o [1+g m R S ]
Background image of page 3

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

View Full DocumentRight Arrow Icon
4 Output Resistances Continued R OUT BJT Q4 = r 04 [1 + g m4 * r π4 || R E4 ] where R E4 = r 02 R OUT BJT Q4 = r 04 [1 + g m4 * r π4 || r 02 ] ≈ r 04 [1 + g m4 r π4 ] because r 02 >> r π4 = r 04 [1 + β 4 ] = V A (1+ β 4 ) / (I o / 2)
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 9

Lecture30 2010 BiCMOSAmpsWithActiveLoads_1 - EE 311 Lecture...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online