843751 Datasheet, PDF (1/17 Pages) Integrated Device Technology – FemtoClock™ SAS/SATA Clock Generator

FemtoClock™ SAS/SATA Clock Generator
843751
DATA SHEET
General Description
The 843751 is a low jitter, high performance clock generator. The
843751 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 843751 has excellent (<1ps)
RMS phase jitter, over the SAS defined integration range. The
843751 uses an external, 25MHz, parallel resonant crystal to
generate 75MHz. This silicon based approach provides excellent
frequency stability and reliability. The 843751 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.
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 systems
• Up, down and center Spread Spectrum Clocking (SSC)
• One differential 3.3V or 2.5V LVPECL output pair
• Output frequency: 75MHz
• RMS phase jitter @ 75MHz, (900kHz – 7.5MHz):
0.734ps (typical) @ 3.3V
• 3.3V or 2.5V operating supply modes
• 0°C to 70°C ambient operating temperature
• Available in lead-free (RoHS 6) package
• Functional replacement part: 843002AYLF
Block Diagram
25MHz
XTAL_IN
XTAL_OUT
OSC
SSC_SEL[1:0] ^Pulldown
FemtoClock™
PLL
Pin Assignment
75MHz
Q
nQ
843751
8-Lead SOIC, 150 Mil
3.90mm x 4.90mm x 1.375mm package body
M Package
Top View
843751 REVISION B 08.21.15
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