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Folded Cascode Op-amp

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Given Values:

Bias voltages: Power Budget=1mW Cu1)V1=1!"#V Vdd=$!#V

B1=#%u&

')V'=%V Vss=-$!#V

B'=#%u&$)V$=-1!"#V BW=1(*

B$='#u&

  Vswing=#VB+='#u&

=

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Calculation:Von calculation:

Von,pmos)=Vsg-Vtp  ,Vtp=-%!)

Von,nmos)=Vgs-Vtn  ,Vtn= %!")

Von,.%)=Vsg-/Vtp/=$!#-1!"#-%!=%!0#V

Von,.0)=Vgs- Vtn  =-1!"#$!#-%!"=1!%#V

&s we 2ave decided t2e output swing as #V3soVdd-Vss=sum,Von)$3#3"30Vswing3so

4um,Von)$3"3#='-Von0='-1!%#=%!0#V

 We are dividing %!0#V among .$3.#3."3as 5ollowing,rea

Von#=%!'#V3Von"=%!'#V3so Von$=%!0#-',%!'#)=%!+#V

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Calculation,cont!)W78 calculation :

&s we (now t2e values o5 Von and 9d 5or t2e mos5ets3 so u

5ollowing e;uation3 we can get t2is ratio6

W78='9d7,(n!0#> as Von=%!'#V39d='#u&

,W78)#3>=1!0" as Von=%!'#V39d='#u&

,W78)1131'31$31+=%!0>$# as Von=%!0#V39d=#%u&

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Calculation,cont!)

Calculation o5 ,W78)1 using gain e;uation:Gain,di?)=gm17gout=@ gm1=Gain,di?) A gout

W2ere3

gout=,gds$!gds"7gm"),gds#,gds1gds0)7gm#)

,1)ere3gds=lamda9d3so

gds$=lamda3p9d=%!''#u=#u4 ,lamda3p%!

lamda3n=%!$)

4imilarl3

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Calculation,cont!)

gm"=,'9d(p

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 E2eoretical vs simulation result

Parameters Theoretical values Practical(simu

values

Gain >>dB ">!10dB

P4 ->!0+dB -%!>$dB

Power dissipation 1%#%uW 1>>!0"uW

Gain BW product #%%.* 0!">.*

4wing #V +!10V

V13'3$ 1!"#3%3-1!"#V 1!0>003'#>mV3-

4lew ate '# V7us %!0'V7us

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Fre;uenc esponse,simulation

Plot wit2 dB:

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Fre;uenc esponse,cont):

% dB BW:

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Fre;uenc esponse,cont):

-$ dB BW:

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Fre;uenc esponse,cont):

4wing:

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Fre;uenc esponse,cont):

4lew ate:

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Fre;uenc esponse,cont):

Common .ode Gain

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8aout o5 t2e 5olded cascode opamp:

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8aout ules:

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  E&D HOI