SY87725L Datasheet, PDF (1/20 Pages) Micrel Semiconductor – 2.5Gbps GPON/BPON ONU SERDES

SY87725L
2.5Gbps GPON/BPON ONU SERDES
General Description
The SY87725L is a single chip transceiver for data rates
up to 2.5Gbps. On the receive side, it includes a
complete clock recovery and data retiming circuit with
an integrated 4-bit serial-to-parallel data converter. On
the transmit side, it includes a synthesizer with an
integrated 4-bit parallel-to-serial data converter.
The SY87725L receiver has a synthesizer that
generates an internal clock from an externally supplied
TTL or PECL REFCLK that can be either 155.52MHz or
77.76MHz. This internal clock can be used by the clock
recovery PLL if an absence of transitions on the input
serial data stream prevents normal clock recovery. This
enables it to provide a stable clock source in the
absence of transitions on the incoming serial data
stream.
The transmit synthesizer uses the CLKIN parallel data
clock to generate its own serial rate clock locked to
CLKIN. This enables the transmit and receive to operate
at different data rates.
The serial interface for both the transmit and receive
functions feature industry standard high-speed
differential CML I/O. The parallel interfaces feature high-
speed LVDS I/O with an internal 100Ω termination on
the LVDS inputs.
The first bit for the serial-to-parallel conversion can be
moved using the RCV_SYNC input. The RCV_SYNC
input enables the parallel word boundary to move up in
time by one bit time for each pulse. This allows it to in
effect “swallow” one bit each time the RCV_SYNC pulse
is asserted.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
• Single 3.3V supply and 1W typ. power consumption
• 2.5G/1.25G/625Mbps down stream
• 1.25G/625M/156Mbps up stream
• 4-bit Serdes with LVDS interfaces
• Serial Data input sensitivity of 30mV typical
• Training mode for fast lock acquisition
• Link Fault Indicator (LFIN: “HIGH” = Locked)
• Separate training and MUX synthesizers
• Loop back function for diagnostics
• TTL–CML Translator for MAC-to-Laser diode driver
burst control
• Selectable double data rate option for low cost
FPGA/ASIC MAC implementation
• Available in Pb-Free (10mm x 10mm) 64-pin
EPAD-TQFP
Applications
• BPON/GPON/GEPON/EPON
Markets
• FTTH/FTTP
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
February 2007
M9999-021607-A
[e-mail] or [phone]