2

12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012

12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012

12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012

PS8451B

03/28/01

PI6C9911 & PI6C9911E

5V High Speed Programmable Skew

e

m

a

N

l

a

n

g

i

SO

/

In

o

it

p

i

r

c

s

e

D

F

E

R

I

ll

a

h

ci

h

w

e

c

n

e

r

e

f

e

r

g

n

i

m

it

d

n

a

y

c

n

e

u

q

e

rf

e

h

t

s

ei

l

p

p

u

s

t

u

p

n

i

si

h

T

.t

u

p

n

i

y

c

n

e

u

q

e

rf

e

c

n

e

r

e

f

e

R

.

d

e

r

u

s

a

e

m

si

n

o

it

ai

r

a

v

l

a

n

o

it

c

n

u

f

B

F

.)

st

u

p

t

u

o

t

h

g

i

e

e

h

t

f

o

e

n

o

o

t

d

e

t

c

e

n

n

o

c

y

ll

a

ci

p

y

t(

t

u

p

n

i

k

c

a

b

d

e

e

f

L

L

P

S

F.t

c

el

e

s

e

g

n

a

r

y

c

n

e

u

q

e

rf

l

e

v

el

-

e

e

r

h

T

1

el

b

a

T

e

e

S

.

1

F

1

,

0

F

1

.)

1

Q

1

,

0

Q

1

(

1

ri

a

p

t

u

p

t

u

o

r

o

f

st

u

p

n

i

t

c

el

e

s

n

o

it

c

n

u

f

l

e

v

el

-

e

e

r

h

T

2

el

b

a

T

e

e

S

.

1

F

2

,

0

F

2

.)

1

Q

2

,

0

Q

2

(

2

ri

a

p

t

u

p

t

u

o

r

o

f

st

u

p

n

i

t

c

el

e

s

n

o

it

c

n

u

f

l

e

v

el

-

e

e

r

h

T

2

el

b

a

T

e

e

S

.

1

F

3

,

0

F

3

.)

1

Q

3

,

0

Q

3

(

3

ri

a

p

t

u

p

t

u

o

r

o

f

st

u

p

n

i

t

c

el

e

s

n

o

it

c

n

u

f

l

e

v

el

-

e

e

r

h

T

2

el

b

a

T

e

e

S

.

1

F

4

,

0

F

4

.)

1

Q

4

,

0

Q

4

(

4

ri

a

p

t

u

p

t

u

o

r

o

f

st

u

p

n

i

t

c

el

e

s

n

o

it

c

n

u

f

l

e

v

el

-

e

e

r

h

T

2

el

b

a

T

e

e

S

.

T

S

E

T

.s

n

o

it

p

ir

c

s

e

d

m

a

r

g

ai

d

k

c

o

l

b

e

h

t

r

e

d

n

u

n

o

it

c

e

s

e

d

o

m

t

s

e

t

e

e

S

.t

c

el

e

s

l

e

v

el

-

e

e

r

h

T

1

Q

1

,

0

Q

1

O

.

1

ri

a

p

t

u

p

t

u

O

2

el

b

a

T

e

e

S

.

1

Q

2

,

0

Q

2.

2

ri

a

p

t

u

p

t

u

O

2

el

b

a

T

e

e

S

.

1

Q

3

,

0

Q

3.

3

ri

a

p

t

u

p

t

u

O

2

el

b

a

T

e

e

S

.

1

Q

4

,

0

Q

4.

4

ri

a

p

t

u

p

t

u

O

2

el

b

a

T

e

e

S

.

C

C

R

W

P

.s

r

e

v

ir

d

t

u

p

t

u

o

r

o

f

y

l

p

p

u

s

r

e

w

o

P

C

C

.y

rt

i

u

c

ri

c

l

a

n

r

e

t

n

i

r

o

f

y

l

p

p

u

s

r

e

w

o

P

D

N

Gd

n

u

o

r

G

Pin Definitions

Block Diagram Description

Phase Frequency Detector and Filter

These two blocks accept input signals from the reference frequency

(REF) input and the feedback (FB) input and generate correction

information to control the frequency of the Voltage-Controlled

Oscillator (VCO). These blocks, along with the VCO, form a Phase-

Locked Loop (PLL) that tracks the incoming REF signal.

VCO and Time Unit Generator

The VCO accepts analog control inputs from the PLL filter block

and generates a frequency that is used by the time unit generator to

create discrete time units that are selected in the skew mix matrix.

The operational range of the VCO is determined by the FS control

the device and the level of the FS pin as shown in Table 1.

Skew Select Matrix

The skew select matrix is comprised of four independent sections.

Each section has two low-skew, high-fanout drivers (xQ0, xQ1),

and two corresponding three-level function select (xF0, xF1)

inputs. Table 2 shows the nine possible output functions for each

section as determined by the function select inputs. All times are

measured with respect to the REF input assuming that the output