Micrel SY88147DL General Description Manual

General Description

The SY88147DL high-sensitivity,
amplifier is designed for use in fiber-optic receivers.
The device connects 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 SY88147DL quantizes
these signals and outputs PECL-level waveforms.
The SY88147DL operates from a single +3.3V power
supply, over an industrial temperature range of –40°C
to +85°C. With its wide bandwidth and high gain,
signal with data rates up to 1.25Gbps, and as small as
5mV can be amplified to drive devices with PECL
pp
inputs.
The SY88147DL features an open-collector, TTL loss-
of-signal (LOS) indicator. The LOS function has a high
gain input stage for
programmable loss-of-signal level set pin (LOS
sets the sensitivity of the input amplitude detection.
LOS asserts high if the input amplitude falls below the
threshold set by LOS
LVL
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 enable bar (/EN) input to
maintain output stability under a loss-of-signal
condition. Typically, 3.5dB LOS hysteresis is provided
to prevent chattering.
This manual provides information on the SY88147DL
evaluation board. It should be used in conjunction with
the SY88147DL data sheet, which contains the full
specifications of the SY88147DL.
The SY88147DL evaluation board enables fast and
thorough evaluation of the SY88147DL. The board is
an easy-to-use, single supply design. It's designed to
be driven by a high-speed, pattern generator and
provides onboard 50Ω terminations for the generator's
outputs. The input termination network also provides
the required input
SY88147DL.
The SY889147DL evaluation board is intended to
terminate to a 50Ω scope and provides for simple user
adjustability of the LOS threshold through the
adjustment of an on-board potentiometer.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
January 2006
limiting
increased sensitivity.
and de-asserts low otherwise.
bias of V –1.3V for
CC
3.3V, 1.25Gbps PECL Limiting Post
Amplifier with High-Gain TTL Loss-of-
SY88147DL Evaluation Board
All data sheets and support documentation can be
found on Micrel's web site at: www.micrel.com.
post

Features

• Single 3.3V supply
• DC-to-1.25Gbps operation
• Low-noise PECL data outputs
• LOS Indicator
• Chatter-free open-collector TTL loss-of-signal
(LOS) output with internal 4.75kΩ pull-up resistor
• TTL /EN input
• Programmable LOS level set (LOS
• AC-coupled I/O with SMA connectors
• 50Ω input network termination
A

Related Documentation

)
LVL
• SY88147DL, 3.3V, 1.25Gbps PECL Limiting Post
Amplifier w/ High-Gain TTL LOS Data Sheet

Evaluation Board

the
Signal
LVL
M9999-011606-A
hbwhelp@micrel.com or (408) 955-1690
)