SY88149CL_09 Datasheet, PDF (1/10 Pages) Micrel Semiconductor – 3.3V, 1.25Gbps PECL Limiting Post

SY88149CL
3.3V, 1.25Gbps PECL Limiting Post
Amplifier w/High Gain TTL Signal Detect
General Description
The SY88149CL is a high-sensitivity limiting post
amplifier designed for use in fiber-optic receivers. These
devices connect to typical transimpedance amplifiers
(TIAs). The linear signal output from TIAs can contain
significant amounts of noise and may vary in amplitude
over time. The SY88149CL quantizes these signals and
outputs PECL level waveforms.
The SY88149CL 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 with data
rates up to 1.25Gbps, and as small as 5mV_pp, can be
amplified to drive devices with PECL inputs.
The SY88149CL generates a high-gain signal-detect
(SD) open-collector TTL output. The SD function has a
high gain input stage for increased sensitivity. A
programmable Signal Detect level set pin (SD_LVL) sets
the sensitivity of the input amplitude detection. SD
asserts high if the input amplitude rises above the
threshold set by SD_LVL and de-asserts low otherwise.
The enable input (EN) de-asserts the true output signal
without removing the input signal. The SD output can be
fed back to the EN input to maintain output stability
under a loss-of-signal condition. Typically, 3.4dB SD
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 SD enable/disable time
∑ 622Mbps to 1.25Gbps operation
∑ Low-noise PECL data outputs
∑ High-gain SD
∑ Chatter-free Open-Collector TTL signal detect (SD)
output with internal 4.75kΩ pull-up resistor
∑ TTL EN input
∑ Programmable SD level set (SD_LVL)
∑ Available in a tiny 10-pin MSOP package
Applications
∑ GE-PON/GPON/EPON
∑ Gigabit Ethernet
∑ 1062Mbps Fibre Channel
∑ OC-12/24 SONET/SDH
∑ High-gain line driver and line receiver
∑ Low-gain TIA interface
Markets
∑ FTTH/FTTP
∑ Datacom/Telecom
∑ Optical transceiver
January 2009
1
M9999-011609-C
[e-mail] or [phone]