Line Card Protection Switch for
SONET/SDH Systems
ACS8525 LC/P
PRELIMINARY
PRODUCT BRIEF
ADVANCED COMMUNICATIONS
COMMUNICATION
Description
The ACS8525 is a highly integrated, single-chip solution
for 鈥淗it-less鈥?protection switching of SEC (SDH/SONET
Equipment Clock) + Sync clock 鈥淕roups鈥? from Master
and Slave SETS clock cards and a third (Stand-by) source,
for Line Cards in a SONET or SDH Network Element. The
ACS8525 has fast activity monitors on the SEC clock
inputs and will implement automatic system protection
switching against the Master clock failure. The selection
of the Master/Slave input can be forced by a Force Fast
Switch pin. If both the Master and Slave input clock fail,
the Stand-by 鈥淕roup鈥?is selected or, if no Stand-by is
available, the device enters Digital Holdover mode.
The ACS8525 can perform frequency translation,
converting, for example, an 8 kHz SEC input clock from a
backplane into a 155.52 MHz clock for local line cards.
Master and Slave SEC inputs to the device support
TTL/CMOS and PECL/LVDS. The Stand-by SEC and three
Sync inputs are TTL/CMOS only.
The ACS8525 generates two SEC clock outputs, via one
PECL/LVDS and one TTL/CMOS port, with spot
frequencies from 2 kHz up to 311.04 MHz (up to
155.52 MHz on the TTL/CMOS port). It also provides an
8 kHz Frame Sync and a 2 kHz Multi-Frame Sync signal
output with programmable pulse width and polarity.
The ACS8525 includes a Serial Port, which can be SPI
compatible, providing access to the configuration and
status registers for device setup.
IEEE 1149.1 JTAG Boundary Scan is supported.
Features
SONET/SDH applications up to OC-3/STM-1 bit rates
Switches between grouped inputs (SEC/Sync pairs)
Inputs: three SECs at any of 2, 4, 8 kHz (and N x 8 kHz
multiples) up to 155.52 MHz, plus Frame Sync/Multi-
Frame Sync
Outputs: two SEC clocks at any of several spot
frequencies from 8 kHz up to 77.76 MHz via the
TTL/CMOS port and up to 155.52/311.04 MHz via the
PECL/LVDS port
Selectable clock I/O port technologies
Modes for E3/DS3 and multiple E1/DS1 rate output
clocks
Generates 8 kHz Frame Sync and 2 kHz Multi-Frame
Sync output clocks with programmable pulse width
and polarity
Frequency translation of SEC input clock to a different
local line card clock
Robust input clock source activity monitoring on all
inputs
Supports Free-run, Locked and Digital Holdover
modes of operation
Automatic 鈥淗it-less鈥?source switchover on loss of input
External force fast switch between SEC1/SEC2 inputs
Phase Build-out for output clock phase continuity
during input switchover
PLL 鈥淟ocked鈥?and 鈥淎cquisition鈥?bandwidths
individually selectable from 18, 35 or 70 Hz
Serial interface for device set-up
Single 3.3 V operation, 5 V I/O compatible
Operating temperature (ambient) of -40 to +85擄C
Available in LQFP 64 package
Block Diagram
Figure 1
Block Diagram of the ACS8525 LC/P
3 x SEC/Sync Input Groups
SEC1 & SEC2:
TTL/PECL/LVDS,
SEC3 and all Syncs
TTL only
SEC1
Master
SYNC1
SEC2
Slave
SYNC2
SEC3
Stand-by
SYNC3
SEC Inputs:
Programmable
Frequencies
2 kHz, 4 kHz,
TCK
N x 8 kHz
TDI
1.544/2.048 MHz
TMS
6.48 MHz
TRST
19.44 MHz
TDO
25.92 MHz
38.88 MHz
51.84 MHz
77.76 MHz
155.52 MHz
DPLL1
Input
SEC Port
Monitors
and
Input
Selection
Control
DPLL2
MUX
2
APLL2
Output
Port
Frequency
Selection
MUX
1
APLL 1
SEC Outputs:
01 (PECL/LVDS)
02 (TTL)
Selector
Digital Feedback
E1/DS1
Synthesis
APLL3
Sync Outputs:
MFrSync 2 kHz (TTL)
FrSync 8 kHz (TTL)
01 and 02:
E1/DS1 (2.048/1.544 MHz)
and frequency multiples:
1.5x, 2x, 3x, 4x, 6x, 12x,
16x, and 24x E1/DS1
E3/DS3, 2 kHz, 8 kHz.
and OC-N* rates: OC-1 51.84 MHz
OC-3 155.52 MHz and derivatives:
6.48 MHz (O2 port only)
19.44 MHz, 25.92 MHz,
38.88 MHz, 51.84 MHz, 77.76 MHz,
155.52 MHz (01 port only)
311.04 MHz (01 port only)
F8525D_001BLOCKDIA_05
IEEE
1149.1
JTAG
Chip
Clock
Generator
Priority Register Set
Table
Serial Interface
Port
TCXO or
XO
Revision 2.00/January 2003 漏 Semtech Corp.
Page 1
www.semtech.com
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