VITESSE
SEMICONDUCTOR CORPORATION
Data Sheet
VSC8122
Features
• Multi-Rate OC-3, OC-12, OC-24, OC-48 Clock
and Data Recovery
• Supports Gigabit Ethernet
• Differential Back Terminated I/O
• Maintains Clock Output in the Absence of Data
• Selectable Reference Clock
Multi-Rate SONET/SDH
Clock and Data Recovery IC
• Loss of Lock Indicator
• Exceeds SONET/SDH Requirements for Jitter
Tolerance, Jitter Transfer and Jitter Generation.
• 3.3V Supply Operation
• 1W Typical Power
• 64-pin , 10x10mm PQFP Packaging
General Description
The VSC8122 is a single-chip clock recovery IC for use in SONET OC-48, OC-24, OC-12, OC-3, or Giga-
bit Ethernet systems operating at their respective 2.48832Gb/s, 1.24416Gb/s, 622.08Mbps, 155.52Mbps, or
1.25Gbps data rates. The VSC8122 complies with SONET jitter tolerance, jitter transfer and jitter generation
specifications.
Alarm functions support typical telecom system applications. The Loss of Lock (LOL) output indicates
when the device goes out of lock, which would most often occur in the event of a loss of valid data. The NOREF
output flags when the reference input to the VSC8122 either is removed, or goes severely out of tolerance.
VSC8122 Block Diagram
FILTO+/- FILTI+/-
FSEL[1:0]
DI+
DI-
Ph/Freq.
Detector
Loop
Filter
VCO
Divider
CO+
CO-
Data
Retiming
REFCK1 +/-
REFCK0 +/-
Lock
Detect
DO+
DO-
LOL
NOREF
Divider
REF_INPUTSEL
REF_SEL[1:0]
G52228-0, Rev 4.1
01/05/01
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
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