3.3V/5V 3.2Gbps CML
SY88773V
Micrel, Inc.
LOW-POWER LIMITING POST
AMPLIFIER WITH TTL LOS
SY88773V
DESCRIPTION
FEATURES
■ Multi-rate up to 3.2Gbps operation
■ Wide gain-bandwidth product
• 38dB differential gain
The SY88773V low-power, limiting post 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 SY88773V
• 2GHz 3dB bandwidth
quantizes these signals and outputs typically 800mV
voltage-limited waveforms.
The SY88773V operates from a single +3.3V ±10% or
+5V ±10% power supply, over an industrial temperature
range of –40°C to +85°C. With its wide bandwidth and high
gain, signals with data rates up to 3.2Gbps and as small as
PP
■ Low noise 50Ω CML data outputs
• 800mV output swing
PP
• 60ps edge rates
• 5ps
typ. random jitter
(RMS)
• 15ps
typ. deterministic jitter
10mV can be amplified to drive devices with CML inputs
pp
(PP)
or AC-coupled PECL inputs.
■ Chatter-free, Loss-of-Signal (LOS) output
• 4.6dB electrical hysteresis
The SY88773V incorporates a loss-of-signal (LOS), open-
collector TTL output with internal 4.75kΩ pull-up resistor. A
programmable, loss-of-signal level set pin (LOSLVL) sets
the sensitivity of the input amplitude detection. LOS asserts
high if the input amplitude falls below the threshold set by
LOSLVL and de-asserts low otherwise. LOS can be fed
back to the enable (/EN) input to maintain output stability
under a loss-of-signal condition. /EN de-asserts the true
output signal without removing the input signal. Typically
4.6dB LOS hysteresis is provided to prevent chattering.
Please see Micrel’s website at www.micrel.com for a
complete selection of optical module ICs. The following table
summarizes the differences between devices in Micrel’s
latest family of Limiting Amplifiers.
• OC-TTL output with internal 4.75kΩ pull-up
resistor
■ Programmable LOS sensitivity using single external
resistor
■ Integrated input bias reference
■ TTL /EN input allows feedback from LOS
■ Wide operating range
• Single 3.3V ±10% or 5V ±10% power supply
• –40°C to +85°C industrial temperature range
■ Available in tiny 10-pin EPAD-MSOP and
All support documentation can be found on Micrel’s web
site at www.micrel.com.
16-pin MLF™ packages
Integrated 50Ω
Part Number Input Termination or SD or HIGH Enable
LOS
Active LOW
APPLICATIONS
SY88773V
SY88823V
SY88843V
SY88973V
No
LOS
SD
LOW
HIGH
HIGH
LOW
■ 1.25Gbps and 2.5Gbps Gigabit Ethernet
■ 1.062Gbps and 2.125Gbps Fibre Channel
No
Yes
Yes
SD
■ 155Mbps, 622Gbps, 1.25Gbps, and 2.5Gbps SONET/
SDH
LOS
■ Gigabit interface converter (GBIC)
Table 1. Limiting Amplifiers Selection Guide
■ Small form factor (SFF) and small form factor
TYPICAL PERFORMANCE
pluggable (SFP) transceivers
■ Parallel 10G Ethernet
3.3V, 25°C, 10mVpp Input
@3.2Gbps 231–1 PRBS, RLOAD = 50Ω to VCC
■ High-gain line driver and line receiver
TIME (50ps/div.)
Micro LeadFrame and MLF are trademarks of Amkor Technology
Rev.: C
Amendment: /0
M9999-110905
hbwhelp@micrel.com or (408) 955-1690
1
Issue Date: November2005