Basic Current Mirrors and Single- Stage Amplifiers g p

Basic Current Mirrors and Single‐

Basic Current Mirrors and Single‐

Stage Amplifiers g p

Hossein Shamsi Hossein Shamsi

١

Simple Current Mirror

ds out

W r r

⎜ ⎞

⎛

=

₂

in

out

I

W L W

I ⎛ ⎞

⎠

⎜ ⎞

⎝

⎛

=

² _in

out

L W ⎟

⎠

⎜ ⎞

⎝

⎛

1

eff

out

V

V ≥

٢

Common‐Source Amplifier

٣

Source‐Follower or Common‐Drain Amplifier

g_s1 denotes the body effect. (g_s1 =g_mb1) g_s1 denotes the body effect. (g_s1 g_mb1)

۴

Common‐Gate Amplifier

2 ds

L

r

R =

۵

Common‐Gate Amplifier

۶

Source‐Degenerated Current Mirrors

in

out

I

L I W L

if W ⎟ ⇒ =

⎠

⎜ ⎞

⎝

= ⎛

⎟ ⎠

⎜ ⎞

⎝

⎛

2

1

L

L ⎠ ⎝ ⎠

⎝

1 2

eff out

s

out

R I V

V ≥ +

٧

High‐Output‐Impedance Current Mirrors

Cascode Current Mirror Wilson Current Mirror

٨

Cascode Current Mirror

L I W

I

²

⎟ ⎠

⎜ ⎞

⎝

⎛

=

_in

out

I

L I W

1

⎟ ⎠

⎜ ⎞

⎝

= ⎛

٩

Wilson Current Mirror

L W ⎟

⎠

⎜ ⎞

⎝

⎛

in

out

I

L W

I L

²

⎟ ⎠

⎜ ⎞

⎝

⎛

⎠

= ⎝

L ⎠

₁

⎝

١٠

CASCODE Gain Stage

telescopic-cascode amplifier folded-cascode amplifier

١١

Telescopic‐Cascode Amplifier

R

R ||

out m

V

L d

out

R g

A

R r

R

×

−

≅

=

1 2

||

The folded-cascode amplifier is analyzed similarly.

١٢

Differential Pair Differential Pair

After a few manipulation, it

i th t

r r

r ≅

is proven that:

2 4 ds ds

out

r r

r ≅

Besides, we have:

i

g v

g v i

i

_sc

≅ 2 i

_s

2 g

_m

g

_m

v

_i

i

_{1 1 1}

2 2

2 = =

≅

So the voltage-gain is obtained:

So, the voltage gain is obtained:

out m

V

g r

A =

Frequency Response

Common‐Source Amplifier Common Source Amplifier

١۴

Frequency Response Common‐Source Amplifier p

Assuming that poles are real numbers and ω_p1<< ω_p2, we have:

١۵

Frequency Response Common‐Source Amplifier p

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

( ) g R

A 0 = −

_{m1 2}

b

= 1 ω

0

a Q = b

Si il l l th C D d C G lifi

١۶

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

Frequency Response CASCODE Amplifier p

p

R C R C

1 1

1

≅ ≅

ω

2

g

m

ω ≅

L out d

out

p¹

R C

₂

R C

2 2

s

p

≅ C

ω

١٧