ETC CXB1820ER

2.5Gbps Post Amp
product turn-around time dominates the decision-making process for the customer in vendor selection. The exponential growth in optical technology, due to these high bandwidth
requirements, along with competition in optical components, makes the customer more
demanding and specific about the product
requirement.
High bandwidth demand
The increasing demand for high-bandwidth in different application related to the
Internet, telecommunications, data communications, fiber channel, etc. has created a
tremendous need for fiber rich networks and
the components that support them. To meet
these high bandwidth requirements, the fast
SONY
Optical Fiber
Pre-Amp
Post-Amp
Photo
Diode
CDR
DeMux
Phase
Modulation
Switch
Fabric
Optical Fiber
SONY
Laser
Diode
Laser
Diode
Driver
ode
Multiplexer
Converter
Phase
Modulation
Figure 1. Optical Networking Block Diagram
• Time to market
• Better, faster, most cost efficient, and scalable
• The development cycle
• Meet all the Standard’s specifications
• Marketing and the technical support provided by the vendor
Industry’s Requirements
After studying the market, the customer
has to decide which component is appropriate
for their application. Then, they must develop
an optical module based on the project’s fundamental requirements such as:
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©Copyright 2001, Sony Electronics Inc. All rights reserved.
This is an ideal product for fiber optics
applications. This high-speed Post Amplifier
with Signal Detector, CXB1820, is part of
Sony’s family of 2.5Gbps optical networking
ICs for use in high-performance optical transmitter and receiver functions. It can also be
used in Fiber Channel (2.1Gb/s) applications.
• Evaluation board availability and above all,
the brand name, which is important from
service point of view.
• Compact package size, if needed available
even in wafer form
• Complete specification and application
notes for the product
• The vendor’s roadmaps on products in the
pipeline.
• A back up solution in case the vendor discontinues the product
The Sony’s CXB1820 has design flexibility and meets the needs for performance, reliability, and cost. It comes in a compact 24-pin
VQFN plastic package with a fine lead pitch
of 0.4mm and has been used in the fiber optics
applications. A typical SONET application in
which this product can fully utilize it’s features is an OC-48 module, giving a data rate
2.488 Gbps.
Qualifying Tests
Qualification of these devices is time consuming. The customer needs to perform multiple tests, including:
• Electro-optical test, which requires several
weeks
• Life time tests, which takes a few months
• Fulfill all standards (ITU / Bellcore) specifications
• Check AC / DC characteristics & Power
consumption
• The vendor provides temperature characteristics and package qualification.
About Sony’s Post-Amp
This bipolar post amplifier has an edge
over existing parts in the market and fulfills
the industry requirements. The key receiver
function provides reshaping and regenerating
on a single chip with one power supply of
+3.3V.
A typical optical communication system
needs an alarm function, which asserts the
alarm signal at a very low bit error rate (>1E3). The signal detector in the CXB1820 will
assert an alarm signal at input voltage 24mVpp. The hysteresis width for this chip is
designed to maintain a constant gain of 6db
whereas the typical values are 3db.
Why Sony’s Post Amp
Sony has a line of optical communication
products and a promising road map including
10Gbps follow-on products. Based on the criteria and concerns, one of the high-performance optical networking products is our
Post-Amp.
This post-amp has the power and chipcount savings that can translate into better utilization of the real estate on an optical module
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Other features for the post-amp include:
or printed circuit board. This leads to cost savings to the designer on both fiber-based data
communication and telecom solutions. The
typical signal which is received from a pre
amplifier is weak, so the post amplifier should
have high sensitivity; this high sensitivity is
provided in the CXB1820.
•
•
•
•
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The evaluation board is equipped with a
dual supply capability in order to connect
ECL outputs to measuring instruments.
Auto offset cancel circuit
Signal interruption alarm output
Stabilized Signal Detect output function
TTL/ECL/PECL support
Squelch circuit
Application
Typical applications for the post amp are:
• SONET /SDH transmission systems and
modules.
• OC-48 fiber optic modules
• Gigabit Ethernet
• Fiber Channel up to 2.1Gbps
Photo
Diode
Post-Amp w/ signal detect
Pre-Amp
CXB1820
Data
Clock /
Data
Recovery
DeMux
1:n
Clock
Signal
Detector
Figure 2. Typical Receiver Unit for SONET / SDH Fiber System
the CDR is an industry standard. The basic
approach to accomplish the CDR adopted is
through Phase Lock Loop (PLL).
This gives the customer an additional
option to choose clock data recovery (CDR)
integrated with post-amp or independent
CDR. The interface between the post-amp and
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power supply of 3.3V,the key receiver function inclusive of reshaping and regenerating
provides retiming as well. No reference clock
is required and current mode logic (CML)
mode is added.
Integrated Post Amp & Clock/ Data
Recovery
After analyzing the market trends, for
high-speed and integration, Sony has integrated the post amp with clock and data recovery
(CDR) into a single chip, the CXB1826. It
comes in a 48-pin VQFN package. With one
Photo
Diode
Post-amp + Clock / Data Recovery (CXB1826)
Pre-amp
Post-amp
CDR
Data
Signal
Detector
Clock
Figure 3. Typical Receiver Unit with Integrated Post-amp and CDR
for SONET / SDH Fiber System
tion is possible though not desirable in all
cases, this provides the customer more room
for flexibility.
Conclusions
Benefits
• Available both as post amp and post amp
integrated with CDR @ 2.5Gbps
• Good sensitivity
• Stable signal detect function
• Signal detect hysteresis width of 6dB max
• Supports both TTL/PECL output for signal
detect
Embracing this growing market trend,
Sony will provide more integrated devices
and high-speed optical components that reach
up to 10 Gbps. These devices will be available
in wafer form as well. Sony’s product
roadmap includes products such as Post-Amp,
Laser Diode Driver (LDD), Clock & Data
Recovery (CDR) and Pre-Amp.
As fiber optics data communication products, are growing at a rapid pace, higher
speeds, compact sizes and increased functionality is imminent. Even though more integra-
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