Cadence / DSD 4 / EE560_DynLog

LOGIC “0” TRANSFER:

Vin

= 0

S

D

Vx

Assume at t = 0:

MP

ID

C

Vx (t = 0) = Vmax = VDD - VT,MP

x

CK = 0 -> VDD

CK

VGS = VDD, VDS = Vmax = VDD - VT,MP

VDS £ VGS - VT,MP => nMOS in LIN

- C

dVx

=

kn

(2(V - V

)V - V2 )

NOTE VSB = 0

x

dt

2

DD

T,MP

x

x

t

= -

2 Cx

Vx

dVx

ò dt

ò

kn

2

0

VDD −VT,MP (2(VDD - VT,MP )Vx - Vx )

t =

2C

é2(VDD - VT,MP )- Vx

ùö

V

x

lnê

ú |VDD −VT , M P

k (V - V

)

ç

ë

V

÷

n

DD

T,MP è

x

û

ø

12

t =

2C

x

æ

é2(VDD - VT,MP )- Vx

ùö

V

lnê

ú

x

ç

|VDD −VT , M P

Vx

÷

kn (VDD - VT,MP )è

ë

ø

û

t =

Cx

é2(VDD - VT,MP )- Vx

ù

kn (VDD - VT,MP )

lnê

Vx

ú

V (t)

ë

û

x

Transfers a STRONG logic “0”

Vmax

VDD - VT,MP

tfall = t10% - t90%

é(2 - 0.9)(VDD - VT,MP )ù

t

90% =

Cx

(VDD

- VT,MP )

lnê

0.9(VDD - VT,MP )

ú

kn

ë

û

t

Cx

æ 1.1ö

= kn (VDD - VT,MP )lnè 0.9ø

Cx

tfall = 2.74

t10%

=

Cx

lnæ1.9ö

(VDD - VT,MP )

kn

kn (VDD - VT,MP )

è 0.1ø

At t = 0 CK = 0, Vx = Vmax, Vin = 0 V

VDD

M2

n

+

Cx

n+

Isubsthreshold

p - Sub

Ireverse

Ileakage = Isubthreshold + Ireverse

Vin

= 0

V = 0

Ileakage

V

CK

x

n

+

Cx

Isubsthreshold

n+

p - Sub

Ireverse

Ileakage = Isubthreshold + Ireverse

Ileakage

Vx

Isubthreshold

Cj

Cin

Ireverse

Cin = Cgb + Cpoly + Cmetal

VT0 = 0.8 V

C

= 0.065 fF/μm2

18

ox

γ = 0.4 V1/2

C’metal = 0.036 fF/μm2

|2φF| = 0.6 V

C’poly = 0.055 fF/μm2

1μ

φ0 = 0.88 V

C

j0

= 0.095 fF/μm2

φ0sw = 0.95 V

C

= 0.2 fF/μm

j0sw

Ileakage,max = 0.85 pA

3μ

6μ

5μ

6μ

3μ

1μ

4μ

5μ

2μ

2μ

1μ

diffusionmetal

4μ

poly

CK

C = C

ox

W L

mask

= 0.065 fF/μm2 (4 μm x 2 μm) = 0.52 fF

gb

C

= C’

metal

W L

metal

= 0.036 fF/μm2 (5 μm x 5 μm) = 0.90 fF

metal

C

= C’

poly

W L

poly

= 0.055 fF/μm2 (36 μm2 + 6 μm2 + 2 μm2) = 2.42 fF

poly

C

= C

A

= 0.095 fF/μm2 (36 μm2 + 12 μm2) = 4.56 fF

bottom

j0

bottom

Csidewall = Cj0swPsidewall = 0.2 fF/μm (30 μm) = 6.00 fF