SY88149HL
3.3V 1.25Gbps Burst-Mode Limiting
Amplifier with Ultra-Fast Signal Assert
Timing
General Description
Features
The SY88149HL is a high-sensitivity, burst-mode capable
limiting post amplifier designed for Optical Line Terminal
(OLT) receiver applications. The SY88149HL 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 SY88149HL generates a high-gain LOS or SD LVTTL
output. A programmable LOS/SD level pin (LOS/SDLVL)
sets the sensitivity of the input amplitude detection. This
device also offers the option to choose between a Loss-ofSignal (LOS) and a Signal-Detect (SD) output from the
LOS/SD pin based the LOS/SDSEL pin setting. To select
SD output, leave LOS/SDSEL pin open or connect to Vcc;
to select LOS output, tie LOS/SDSEL-to-ground. If the
input signal amplitude falls below the threshold set by
LOS/SDLVL, LOS will assert high (or SD will de-assert low).
Once the input signal rises above the threshold set by
LOS/SDLVL, LOS will de-assert low (or SD output will
assert high). The SY88149HL also features a JAM function
which, when active, disables the LVPECL outputs. JAM is
active LOW when SD is selected and active HIGH when
LOS is selected. The LOS/SD output should be fed back to
the JAM input to maintain output stability under an invalid
signal condition. Typically, 3dB SD hysteresis is provided
to prevent chattering.
The SY88149HL operates from a single +3.3V power
o
o
supply over temperatures ranging from –40 C to +85 C.
With its wide bandwidth and high gain, signals up to
1.25Gbps and as small as 4mVpp can be amplified to
drive devices with LVPECL inputs.
• Single 3.3V power supply
• <5ns SD assert (LOS de-assert) time
• Option to AUTORESET or Manual RESET LOS output
to HIGH and SD output to LOW
• Option to select LOS or SD output
• Up to 1.25Gbps operation
• Low-noise differential LVPECL data outputs
• 4mVpp input sensitivity
• High sensitivity LOS/SD detect
• Ultra fast LVTTL LOS/SD output
• Squelching function to disable output
• Programmable LOS/SD level set (LOS/SDLVL)
• Available in a 16-pin (3mmx 3mm) QFN package
Applications
•
•
•
•
•
•
GE-PON/GPON/EPON OLT
Gigabit Ethernet
Fibre Channel
OC-3/12/24 SONET/SDH
High-gain line driver and line receiver
Low-gain TIA interface
Markets
• FTTH/FTTP
• Datacom/Telecom
• Optical transceiver
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 2010
M9999-061110-I
hbwhelp@micrel.com or (408) 955-1690
