SY88149NDL_12 Datasheet, PDF (1/13 Pages) Micrel Semiconductor – 1.25Gbps Burst-Mode Limiting Amplifier

SY88149NDL
1.25Gbps Burst-Mode Limiting Amplifier
with Ultra-Fast Signal Assert Timing
General Description
The SY88149NDL is a high-sensitivity, burst-mode
capable limiting post amplifier designed for Optical Line
Terminal (OLT) receiver applications. The SY88149NDL
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 SY88149NDL 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
Vcc, 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, 4–5 dB SD hysteresis is
provided to prevent chattering.
The SY88149NDL also features a selectable proprietary
Noise Discriminator that aids by filtering out input signals
that do not qualify as a 1.25Gbps GPON preamble signal
in the initial startup phase. This feature minimizes false SD
Asserts that can be triggered by random noise.
The SY88149NDL operates from a single +3.3V power
supply, over temperatures ranging from –40^oC to +85^oC.
With its wide bandwidth and high gain, signals up to
1.25Gbps and as small as 5mVpp can be amplified to
drive devices with LVPECL inputs.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Features
• <5ns SD Assert (LOS Deassert) time
• Option to AUTO RESET or manual RESET LOS/SD
output
• Selectable LOS/SD output option
• High-sensitivity LOS/SD signal detect
• Low-noise LVPECL data outputs
• Squelching function to maintain output stability
• Programmable LOS/SD level set (LOS/SD_LVL)
• 5mVpp input sensitivity
• 1.25Gbps operation
• Single 3.3V power supply
• Available in a 16-pin (3mm × 3mm) QFN^® package
Applications
• GE-PON/GPON OLT
• Gigabit Ethernet
• Fibre Channel
• OC-3/12/24 SONET/SDH
• High-gain line driver and line receiver
• Low-gain TIA interface
Markets
• FTTH PON
• Datacom/Telecom
• Optical transceiver
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
February 2012
M9999-020712-A
[e-mail] or [phone]