FemtoClock™ SAS/SATA Clock Generator
ICS844441I
PRELIMINARY DATA SHEET
General Description
Features
The ICS844441I is a low jitter, high performance clock
• Designed for use in SAS, SAS-2, and SATA systems
• Center ( 0.25%) Spread Spectrum Clocking (SSC)
• Down (-0.23% or -0.5%) SSC
S
IC
generator and a member of the FemtoClock™ family
of silicon timing products. The ICS844441I is designed
for use in applications using the SAS and SATA
interconnect. The ICS844441I uses an external,
HiPerClockS™
• Better frequency stability than SAW oscillators
• One differential 2.5V LVDS output
25MHz, parallel resonant crystal to generate four selectable output
frequencies: 75MHz, 100MHz, 150MHz, and 300MHz. This silicon
based approach provides excellent frequency stability and reliability.
The ICS844441I features down and center spread spectrum (SSC)
clocking techniques.
• Crystal oscillator interface designed for 25MHz
(CL = 18pF) frequency
• External fundamental crystal frequency ensures high reliability
and low aging
• Selectable output frequencies: 75MHz, 100MHz, 150MHz,
Applications
300MHz
• SAS/SATA Host Bus Adapters
• Output frequency is tunable with external capacitors
• SATA Port Multipliers
• RMS phase jitter @ 100MHz, using a 25MHz crystal
• SAS I/O Controllers
(12kHz – 20MHz): 1.1936ps (typical)
• TapeDrive and HDD Array Controllers
• SAS Edge and Fanout Expanders
• HDDs and TapeDrives
• 2.5V operating supply
• -40°C to 85°C ambient operating temperature
• Available in lead-free (RoHS 6) packages
• Disk Storage Enterprise
Pin Assignment
Block Diagrams
1
2
3
4
8
7
6
5
XTAL_OUT
XTAL_IN
SSC_SEL0
SSC_SEL1
GND
nQ
Q
XTAL_IN
VDD
25MHz
XTAL
00 = SSC Off
FemtoClock™
OSC
01 = 0.5% Down-spread
10 = 0.23% Down-spread
11 = 0.5% Center-spread
Q
ICS844441I
PLL
nQ
XTAL_OUT
8-Lead SOIC, 150 mil
3.90mm x 4.90mm x 1.375mm package body
M Package
SSC Output
Control Logic
Pulldown:Pulldown
SSC_SEL(1:0)
nPLL_SEL
8-Lead SOIC
Top View
Pulldown
GND
16
15
14
13
12
11
10
9
F_SEL1
GND
nPLL_SEL
nQ
Q
VDD
1
2
3
4
5
6
7
8
XTAL_IN
XTAL_OUT
XTAL_IN
FemtoClock™
PLL
25MHz
XTAL
OSC
0
1
00 = 75MHz
SSC_SEL0
01 = 100MHz
Q
nc
nc
nc
XTAL_OUT
10 = 150MHz (default)
11 = 300MHz
nQ
Pullup:Pulldown
F_SEL(1:0)
F_SEL0
VDD
SSC_SEL1
Clock Output
Control Logic
Pulldown:Pulldown
SSC_SEL(1:0)
16-Lead TSSOP
ICS844441I
16-Lead TSSOP
4.4mm x 5.0mm x 0.925mm package body
G Package
Top View
The Preliminary Information presented herein represents a product in pre-production. The noted characteristics are based on initial product characterization
and/or qualification. Integrated Device Technology, Incorporated (IDT) reserves the right to change any circuitry or specifications without notice.
ICS844441DGI REVISION B OCTOBER 13, 2009
1
©2009 Integrated Device Technology, Inc.