1

SY88773V

Micrel, Inc.

M9999-110905

hbwhelp@micrel.com or (408) 955-1690

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

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

or AC-coupled PECL inputs.

The SY88773V incorporates a loss-of-signal (LOS), open-

collector TTL output with internal 4.75k

Ω 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.

All support documentation can be found on Micrel’s web

site at www.micrel.com.

Integrated 50

Ω

LOS

Active LOW

Part Number

Input Termination

or SD

or HIGH Enable

SY88773V

No

LOS

LOW

SY88823V

No

SD

HIGH

SY88843V

Yes

SD

HIGH

SY88973V

Yes

LOS

LOW

Table 1. Limiting Amplifiers Selection Guide

DESCRIPTION

s Multi-rate up to 3.2Gbps operation

s Wide gain-bandwidth product

• 38dB differential gain

• 2GHz 3dB bandwidth

s Low noise 50

• 60ps edge rates

s Chatter-free, Loss-of-Signal (LOS) output

• 4.6dB electrical hysteresis

• OC-TTL output with internal 4.75k

resistor

s Programmable LOS sensitivity using single external

resistor

s Integrated input bias reference

s TTL /EN input allows feedback from LOS

s Wide operating range

• Single 3.3V

• –40

s Available in tiny 10-pin EPAD-MSOP and

16-pin MLF™ packages

FEATURES

3.3V/5V 3.2Gbps CML

LOW-POWER LIMITING POST

AMPLIFIER WITH TTL LOS

SY88773V

APPLICATIONS

s 1.25Gbps and 2.5Gbps Gigabit Ethernet

s 1.062Gbps and 2.125Gbps Fibre Channel

s 155Mbps, 622Gbps, 1.25Gbps, and 2.5Gbps SONET/

SDH

s Gigabit interface converter (GBIC)

s Small form factor (SFF) and small form factor

pluggable (SFP) transceivers

s Parallel 10G Ethernet

s High-gain line driver and line receiver

Rev.: C

Amendment: /0

Issue Date:

November 2005

Micro LeadFrame and MLF are trademarks of Amkor Technology

TYPICAL PERFORMANCE

@3.2Gbps 2

TIME (50ps/div.)