Ming c wu 9 mos current mirror not this is not a

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Unformatted text preview: Transconductance Example Gm = g m1 EE105, Fall 2013 Lecture 20 – Slide 15 Prof. Ming C. Wu MOS Cascode Amplifier Av = −Gm Rout Av ≈ − g m1 [(1 + g m 2 rO 2 )rO1 + rO 2 ] Av ≈ − g m1rO1 g m 2 rO 2 EE105, Fall 2013 Lecture 20 – Slide 16 Prof. Ming C. Wu 8 PMOS Cascode Current Source as Load §༊  A large load impedance can be achieved by using a PMOS cascode current source. RoN ≈ g m 2 rO 2 rO1 RoP ≈ g m 3 rO 3 rO 4 Rout = RoN || RoP Lecture 20 – Slide 17 EE105, Fall 2013 Prof. Ming C. Wu MOS Current Mirror §༊  The moIvaIon behind a current mirror is to duplicate a (scaled version of the) “golden current” to other locaIons. Current mirror concept Generation of required VGS 1 ⎛ྎ W ⎞ྏ 2 I REF = µnCox ⎜ྎ ⎟ྏ (VX − VTH ) 2 ⎝ྎ L ⎠ྏ REF VX = EE105, Fall 2013 2 I REF + VTH 1 µ nCox (W / L )1 Lecture 20 – Slide 18 Current Mirror Circuitry I copy1 = 1 ⎛ྎ W ⎞ྏ µnCox ⎜ྎ ⎟ྏ (VX − VTH )2 2 ⎝ྎ L ⎠...
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This note was uploaded on 01/22/2014 for the course EE 105 taught by Professor King-liu during the Fall '07 term at University of California, Berkeley.

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