SY88349NDL Datasheet, PDF (1/13 Pages) Micrel Semiconductor – 2.5Gbps Burst-Mode Limiting Amplifier

SY88349NDL
2.5Gbps Burst-Mode Limiting Amplifier
with Ultra-Fast Signal Assert Timing
General Description
The SY88349NDL is a high-sensitivity, burst-mode
capable limiting post amplifier designed for optical line
terminal (OLT) receiver applications. The SY88349NDL
satisfies the strict timing restrictions of the GPON
standards by providing ultra-fast loss-of-signal (LOS) or
Signal-Detect (SD) output. Auto reset and manual reset
options are provided to control LOS/SD output timing. For
increased flexibility, this device also includes an option to
select between LOS or SD output. The device can be
connected to burst-mode capable transimpedance
amplifiers (TIAs) using AC or DC coupling.
The SY88349NDL generates a high-gain LOS or SD
LVTTL output. A programmable LOS/SD level set pin
(LOS/SD_LVL) sets the sensitivity of the input amplitude
detection. When LOS/SD SEL pin is left open or tied to
V_CC, JAM is active high, SD is selected and asserts high if
the input amplitude rises above the threshold sets by
LOS/SD_LVL and de-asserts low otherwise. When LOS/SD
SEL pin is set low or tied to GND, JAM is active low, LOS
is selected and asserts low if the input amplitude rises
above the threshold sets by LOS/SD_LVL and de-asserts
high otherwise. The LOS/SD output can be fed back to the
JAM input to maintain output stability under an invalid
signal conditions. Typically, 4dB  5dB SD hysteresis is
provided to prevent chattering.
The SY88349NDL also features a selectable proprietary
noise discriminator that aids by filtering out input signals
that do not qualify as a 2.5Gbps GPON preamble signal in
the initial startup phase. This feature minimizes false SD
asserts that can be triggered by random noise.
The SY88349NDL operates from a single +3.3V power
supply, over temperatures ranging from –40C to +85C.
With its wide bandwidth and high gain, signals up to
2.5Gbps and as small as 5mVpp can be amplified to drive
devices with CML inputs.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
 <5ns SD assert (LOS deassert) time
 Proprietary noise discriminator feature
 Option to AUTO RESET or manual RESET LOS/SD
output
 Selectable LOS/SD option
 Up to 2.5Gbps operation
 Low-noise CML data outputs
 5mVpp input sensitivity
 High-sensitivity LOS/SD detect
 LVTTL LOS/SD output with an external pull-up resistor
 Squelching function to disable output
 Programmable LOS/SD level set (LOS/SD_LVL)
 Single 3.3V power supply
 Available in a 16-pin (3mm  3mm) QFN package
Applications
 XGPON.1/GEPON/GPON
 Gigabit Ethernet
 Fibre Channel
 OC-3/12/24/48 SONET/SDH
 High-gain line driver and line receiver
 Low-gain TIA interface
Markets
 FTTH
 Datacom/Telecom
 Optical transceiver
January 2012
2
M9999-010212-C
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