Basic Current Mirrors and Single‐Basic Current Mirrors and Single‐Stage Amplifiersg p

Hossein ShamsiHossein Shamsi

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Simple Current Mirror

dsout

Wrr

⎞⎜⎛

= 2

inout IWLW

I⎞⎛⎠⎞

⎜⎝⎛

= 2inout

LW

⎟⎠⎞

⎜⎝⎛

1

effout VV ≥

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Common‐Source Amplifier

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Source‐Follower or Common‐Drain Amplifier

gs1 denotes the body effect. (gs1 =gmb1)gs1 denotes the body effect. (gs1 gmb1)

۴

Common‐Gate Amplifier

2dsL rR =

۵

Common‐Gate Amplifier

۶

Source‐Degenerated Current Mirrors

inout IILW

LWif =⇒⎟

⎠⎞

⎜⎝⎛=⎟

⎠⎞

⎜⎝⎛

21 LL ⎠⎝⎠⎝ 21

effoutsout VIRV +≥

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High‐Output‐Impedance Current Mirrors

Cascode Current Mirror Wilson Current Mirror

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Cascode Current Mirror

ILW

I 2

⎟⎠⎞

⎜⎝⎛

= inout I

LW

I

1

⎟⎠⎞

⎜⎝⎛

=

٩

Wilson Current Mirror

LW

⎟⎠⎞

⎜⎝⎛

inout I

LWLI 2

⎟⎠⎞

⎜⎝⎛

⎠⎝=

L 1⎠⎝

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CASCODE Gain Stage

telescopic-cascode amplifier folded-cascode amplifier

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Telescopic‐Cascode Amplifier

RR ||

outmV

Ldout

RgARrR×−≅

=

1

2 ||

The folded-cascode amplifier is analyzed similarly.

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Differential PairDifferential PairAfter a few manipulation, it i th t

rrr ≅

is proven that:

24 dsdsout rrr ≅

Besides, we have:

i vgv

gii 22≅ immssc vggii 111 222 ==≅

So the voltage-gain is obtained:So, the voltage gain is obtained:

outmV rgA =

Frequency ResponseCommon‐Source AmplifierCommon Source Amplifier

١۴

Frequency ResponseCommon‐Source Amplifierp

Assuming that poles are real numbers and ωp1<< ωp2, we have:

١۵

Frequency ResponseCommon‐Source Amplifierp

If the poles are complex conjugate, we will write the above transfer function as follows:

( ) RgA m−=0 21

b=

10ω

abQ =

Si il l l th C D d C G lifi

١۶

Similarly, we can analyze the C.D and C.G amplifiers.

Frequency ResponseCASCODE Amplifierp

p CRCR11

1 ≅≅ω

2mg≅ω

Loutdoutp CRCR 21

22

sp C≅ω

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