CMOS operational amplifier design

Discussion in 'Homework Help' started by Mohamad, May 25, 2010.

  1. Mohamad

    Thread Starter New Member

    Jun 16, 2007
    1
    0
    Hello Friends,

    I'm taking an electronics course this semester and i got to do a small homework project like for this course..

    the amplifier is a differential input single ended cmos op amp

    it has to meet the following specs as in the figure

    [​IMG]

    I should use a positive +VDD/2 supply and a negative –VDD/2 supply only.

    The requirement to have VOS = 0 V means that there should be no differential mode offset; for a 0 V differential input and a common-mode input at the midpoint of the common-mode input range, the output should be 0 V under nominal supply conditions.

    I am free to choose the midpoint of the common mode input range.

    The available components are: NMOS transistors, PMOS transistors and resistors. Ideal sources can only be used to generate the supply voltages, not to generate bias currents.

    Device Models

    The device models are encapsulated in a sub-circuit; use:

    x1 d g s b nmos w=10u l=0.13u
    x2 d g s b pmos w=10u l=0.13u

    The sub-circuit definitions are as follows:

    .subckt nmos d g s b params: w=10u l=0.13u
    m0 d g s b nmos_internal w={w} l={l}
    .model nmos_internal
    + nmos level=1 kp=500u vto=0.3 gamma=0.2 phi=0.6
    + ld=0.025u
    + lambda={0.2*exp(0.13u/{l})/exp(1)}
    .ends

    .subckt pmos d g s b params: w=10u l=0.13u
    m0 d g s b pmos_internal w={w} l={l}
    .model pmos_internal
    + pmos level=1 kp=120u vto=-0.3 gamma=0.2 phi=0.6
    + ld=0.025u
    + lambda={0.15*exp(0.13u/{l})/exp(1)}
    .ends

    [​IMG]

    ------------

    i'm finding this very difficult to achieve

    i tried something on a draft and is as follows:

    [​IMG]

    [​IMG]

    am i close to something ??? any suggestions ?? how to assign a value for every transistor ?

    how to complete the schematic ?? and examples close to what i'm going to do

    thank you in advance
     
  2. aimiazri

    New Member

    Jan 7, 2010
    6
    0
    i dont really know act.. but, i have read it.. try to get reference from book CMOS Analog Circuit Design. Philip E. Allen & Douglas R Holberg..
     
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