PRELIMINARY DATA SHEET
ICS844441DGI REVISION B OCTOBER 13, 2009 1 ©2009 Integrated Device Technology, Inc.
FemtoClock™ SAS/SATA Clock Generator ICS844441I
General Description
The ICS844441I is a low jitter, high performance clock
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,
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.
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 TapeDrives
•Disk Storage Enterprise
Features
•Designed for use in SAS, SAS-2, and SATA systems
•Center (±0.25%) Spread Spectrum Clocking (SSC)
•Down (-0.23% or -0.5%) SSC
•Better frequency stability than SAW oscillators
•One differential 2.5V LVDS output
•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,
300MHz
•Output frequency is tunable with external capacitors
•RMS phase jitter @ 100MHz, using a 25MHz crystal
(12kHz – 20MHz): 1.1936ps (typical)
•2.5V operating supply
•-40°C to 85°C ambient operating temperature
•Available in lead-free (RoHS 6) packages
HiPerClockS™
ICS
Block Diagrams
FemtoClock™
PLL
OSC
nPLL_SEL
1
0
25MHz
XTAL
XTAL_IN
XTAL_OUT
00 = 75MHz
01 = 100MHz
10 = 150MHz (default)
11 = 300MHz
Q
nQ
SSC_SEL(1:0)
F_SEL(1:0)
Clock Output
Control Logic
16-Lead TSSOP
FemtoClock™
PLL
OSC
25MHz
XTAL
XTAL_IN
XTAL_OUT
00 = SSC Off
01 = 0.5% Down-spread
10 = 0.23% Down-spread
11 = 0.5% Center-spread
Q
nQ
SSC_SEL(1:0) SSC Output
Control Logic
8-Lead SOIC
Pulldown
Pullup:Pulldown
Pulldown:Pulldown
Pulldown:Pulldown
Pin Assignment
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
nc
SSC_SEL0
XTAL_IN
XTAL_OUT
GND F_SEL1
nPLL_SEL
nQ
Q
VDD
F_SEL0
VDD
SSC_SEL1
GND
nc
nc
ICS844441I
16-Lead TSSOP
4.4mm x 5.0mm x 0.925mm package body
G Package
Top View
1
2
3
4
8
7
6
5VDD
XTAL_OUT
XTAL_IN
SSC_SEL0
GND
Q
nQ
SSC_SEL1
ICS844441I
8-Lead SOIC, 150 mil
3.90mm x 4.90mm x 1.375mm package body
M 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.