DATA SHEET

843751 REVISION B 08.21.15

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©2015 Integrated Device Technology, Inc.

FemtoClock™ SAS/SATA Clock Generator

843751

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

Pin Assignment

843751

8-Lead SOIC, 150 Mil

3.90mm x 4.90mm x 1.375mm package body

M Package

Top View

OSC

FemtoClock™

PLL

Q

nQ

XTAL_IN

XTAL_OUT

SSC_SEL[1:0]

75MHz

25MHz

Pulldown