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FOUR PORT BYPASS AND REPEATER FOR FC-AL
S2072
S2072
February 18, 2000 / Revision D
FEATURES
ANSI X3T11 Fibre Channel Compliant
Monolithic Clock Recovery Unit
– Retimes & Buffers Received Data
– Jitter Peaking < 0.1 dB
Lock Detect Function
– Frequency Detection
Four Port Bypass Circuits
Suitable for both Coaxial and Optical Link
Low Power Operation 0.93 W Typical
106.25 or 53.125 MHz Reference Clock
Compact 10 mm x 10 mm 64 Pin
PQFP Package
3.3 V Supply
Micropower Bipolar Technology
APPLICATIONS
FC-AL Nodes
RAID
JBOD
SAN
GENERAL DESCRIPTION
The Four Port Bypass and Repeater for FC-AL Cir-
cuit is used in full-speed (1.0625 Gb/s) Disk Arrays.
It contains a monolithic Clock Recovery Unit (CRU),
a lock detect feature and four port bypass circuits.
The S2072 may be used to implement a single chip
Arbitrated Loop Port Bypass Retiming Node. The
Figure 1. S2072 Functional Block Diagram
DEVICE
SPECIFICATION
S2072 performs the function of four port bypass cir-
cuits followed by a Clock and Data Retimer (CDR).
The CDR retimes incoming serial data, detects
whether a valid signal is present and outputs a low
jitter serial data stream.
FUNCTIONAL DESCRIPTION
The S2072 functional block diagram is shown in Fig-
ure 1. The S2072 performs two functions. The first
function is a Quad Port Bypass Circuit (PBC) for
nodes in a FC-AL system. The low jitter accumula-
tion of the port bypass path is essential in these
systems. The second function is to restore signal
quality in RAID drives using the FC-AL link configu-
ration. The S2072 clock and data recovery PLL pro-
vides low jitter transfer peaking and high jitter
tolerance. In addition, the lock detect circuit monitors
the incoming signals for frequency, which is useful
for link performance monitoring and detection of
channel present.
Jitter Performance
Input jitter tolerance is defined as the amplitude of
frequency dependent, random and deterministic jitter
that causes the clock recovery PLL to violate the
BER specifications.
The S2072 complies with the minimum jitter toler-
ance requirements proposed by the Fibre Channel
jitter working group when used with differential in-
puts and outputs as shown in Figure 2. In addition,
the S2072 is designed for minimum jitter generation
and jitter transfer specifications. This allows the opti-
mum system design for arbitrated loop architectures.
0
1
0
1
0
1
0
1
DDO0 DDI0
EN0
DDO1
DDI1
EN1
DDO2
DDI2
EN2
DDO3 DDI3
EN3
IN
CDR
OUTP/N
LOCKDET
B
R
L
R
L
L