FEMTOCLOCKS™

SAS/SATA CLOCK GENERATOR

ICS843241

IDT™ / ICS™ SAS/SATA CLOCK GENERATOR

1

ICS843241BG REV. A AUGUST 20, 2008

GENERAL DESCRIPTION

The ICS843241 is a low jitter, high performance clock

generator and a member of the FemtoClocks™ family

of silicon timing products. The ICS843241 is designed

for use in the SAS-2 interconnect and the three

transport protocols that use the SAS-2 interconnect:

Serial SCSI Protocol (SSP), Serial ATA Tunneled Protocol (STP),

and Serial Management Protocol (SMP). The ICS843241 has

excellent (<1ps) RMS phase jitter, over the SAS defined

integration range. The ICS843241 uses an external, 25MHz,

parallel resonant crystal to generate three selectable output

frequencies: 75MHz, 100MHz, 150MHz, and 300MHz. This sili-

con based approach provides excellent frequency stability and

reliability. The ICS843241 features up, down, and center spread

spectrum (SSC) clocking techniques. The up, down and center

SSC will be required in the SAS-2 applications that have three

clock trees in the HBA and expander ASICs (see Applications

Information section, Figure 3).

APPLICATIONS:

• SAS/ SATA Host Bus Adapters

• SATA Port Multipliers

• SAS I/O Controllers

• TapeDrive and HDD Array Controllers

• SAS Edge and Fanout Expanders

• HDDs and Tape Drives

• Disk Storage Enterprise

FEATURES

• Designed for use in SAS-2 systems

• Up, down and center spread spectrum clocking

• One differential 3.3V or 2.5V LVPECL output pair

• Selectable output frequencies: 75MHz, 100MHz, 150MHz,

300MHz

• RMS phase jitter @ 75MHz, (900kHz – 7.5MHz):

0.70ps (typical)

• 3.3V or 2.5V operating supply

• 0°C to 70°C ambient operating temperature

• Available in lead-free (RoHS 6) packages

HiPerClockS™

ICS

BLOCK DIAGRAMS

OSC

FemtoClock™

PLL

Q

nQ

XTAL_IN

XTAL_OUT

SSC_SEL[1:0]

75MHz, 100MHz,

150MHz or 300MHz

See Table 10 for

Ordering Information

25MHz

Pulldown

PIN ASSIGNMENT

XTAL_OUT

XTAL_IN

SSC_SEL0

SSC_SEL1

1

2

3

4

VEE

nQ

Q

VCC

8

7

6

5

ICS843241-XXX

8-Lead SOIC, 150 mil

3.90mm x 4.90mm x 1.37mm package body

M Package

Top View

OSC

F_SEL[1:0]

Q

nQ

XTAL_IN

XTAL_OUT

25MHz

SSC_SEL[1:0]

nPLL_SEL

F_SEL[1:0]

0 0

75MHz

0 1 100MHz

1 0 150MHz

1 1 300MHz

FemtoClock™

PLL

1

0

2

Pulldown

Pulldown

Pullup:Pulldown

PIN ASSIGNMENT

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

ICS843241

16-Lead TSSOP

4.4mm x 5.0mm x 0.92mm package body

G Package

Top View

8-Lead SOIC

16-Lead TSSOP

VEE

XTAL_OUT

XTAL_IN

SSC_SEL0

nc

nc

nc

SSC_SEL1

F_SEL1

VEE

nPLL_SEL

nQ

Q

VCC

F_SEL0

VCC

ADDITIONAL ORDERING INFORMATION TABLE

r

e

b

m

u

N

t

r

a

Pe

g

a

k

c

a

P

y

c

n

e

u

q

e

r

F

t

u

p

t

u

O

G

B

1

4

2

3

4

8

S

C

IP

O

S

S

T

6

1z

H

M

0

0

3

,

z

H

M

0

5

1

,

z

H

M

0

0

1

,

z

H

M

5

7

5

7

-

M

B

1

4

2

3

4

8

S

C

IC

I

O

S

8z

H

M

5

7

0

0

1

-

M

B

1

4

2

3

4

8

S

C

IC

I

O

S

8z

H

M

0

0

1

0

5

1

-

M

B

1

4

2

3

4

8

S

C

IC

I

O

S

8z

H

M

0

5

1

0

0

3

-

M

B

1

4

2

3

4

8

S

C

IC

I

O

S

8z

H

M

0

0

3