SY88353BL_07 Datasheet, PDF (1/11 Pages) Micrel Semiconductor – 3.3V, 3.2 Gbps Limiting Post Amplifier with Programmable Decision Threshold

SY88353BL
3.3V, 3.2 Gbps Limiting Post Amplifier with
Programmable Decision Threshold
General Description
The SY88353BL limiting post amplifier is designed for
use in fiber-optic receivers, and is specially optimized for
WDM applications where optical amplifiers such as
EDFAs and Raman amplifier are used. The device
connects to typical transimpedance amplifiers (TIAs).
The linear signal from TIAs can contain significant
amounts of noise that is unevenly distributed between
top and bottom rails due to the ASE noise generated by
the optical amplifiers, crosstalk, or non-linear effect in
the fiber. In order to optimize the BER in such noisy
conditions, the decision threshold between bit 1 and bit
0, needs to be moved to the rail that contains less noise.
The SY88353BL features a pin at which an external
voltage can be applied to move the crossing point up
and down, from 20% to 80%, for BER optimization
purposes.
The SY88353BL operates from a single +3.3V power
supply, over temperatures ranging from –40^oC to +85^oC.
Signals with data rates from 155Mbps up to 3.2Gbps,
and as small as10mV_pp, can be amplified to drive
devices with CML or PECL inputs.
The SY88353L features a Loss-of-Signal (LOS) open-
collector TTL output. A programmable Loss-of-Signal
level set pin (LOS_LVL) sets the sensitivity of the input
amplitude detection. LOS asserts high if the input
amplitude falls below the threshold sets by LOS_LVL and
de-asserts low otherwise. The enable bar input (/EN)
de-asserts the true output signal without removing the
input signal. The LOS output can be fed back to the /EN
input to maintain output stability under a loss-of-signal
condition. Typically, 3.3dB LOS hysteresis is provided to
prevent chattering.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Features
• Single 3.3V power supply
• Fast LOS release/assert
• 155Mbps to 3.2Gbps operation
• Low-noise CML data outputs
• Chatter-free Open-Collector TTL loss-of-signal (LOS)
output
• TTL /EN input
• Programmable LOS level set (LOS_LVL)
• Programmable Decision Threshold
• Available in a tiny 3mm x 3mm MLF^® package
Applications
• WDM Systems
• Gigabit Ethernet, 1X and 2X Fibre Channel
• SONET/SDH: OC-3/12/24/48 – STM1/4/8/16
• Low-gain TIA interface
Markets
• Datacom/telecom
• Optical transceiver
MLF and MicroLeadFrame are registered trademarks of Amkor Technology.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
February 2007
1
M9999-021707-B
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