843442I Datasheet, PDF (1/14 Pages) Integrated Device Technology – FemtoClock SAS/SATA Clock Generator

FemtoClock™ SAS/SATA Clock Generator
843442
DATA SHEET
General Description
The 843442 is a low jitter, high performance clock generator. The
843442 is designed for use in applications using the SAS and SATA
interconnect. The 843442 uses an external, 25MHz, parallel
resonant crystal to generate two selectable output frequencies:
75MHz and 150MHz. This silicon based approach provides excellent
frequency stability and reliability. The 843442 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
• Two differential 3.3V LVPECL output pairs
• Crystal oscillator interface designed for 25MHz (C_L = 18pF)
frequency
• External fundamental crystal frequency ensures high reliability
and low aging
• Selectable output frequencies: 75MHz, 150MHz
• Output frequency is tunable with external capacitors
• RMS phase jitter at 150MHz (integrated from 12kHz to 20MHz):
1.07ps (typical)
• 3.3V operating supply
• -40°C to 85°C ambient operating temperature
• Available in lead-free (RoHS 6) package
• Functional replacement part: 843002AYLF
Block Diagram
nPLL_SEL ^Pulldown
25MHz
XTAL_IN
XTAL_OUT
OSC
FemtoClock™
PLL
0
1
0 = 75MHz
1 = 150MHz
(default)
F_SEL ^Pullup
SSC_SEL[1:0] ^Pulldown
2
Clock Output
Control Logic
Pin Assignment
VEE 1
16 F_SEL
XTAL_OUT 2
15 VEE
Q0
XTAL_IN 3 14 nPLL_SEL
nQ0
SSC_SEL0 4 13 nQ0
nc 5
12 Q0
Q1
nQ1
nc 6 11 nQ1
nc 7 10 Q1
SSC_SEL1 8
9 VCC
843442
16-Lead TSSOP
4.4mm x 5.0mm x 0.925mm package body
G Package
Top View
843442AG REVISION B 08/21/2015
1
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