General Description

The MAX3746 multirate limiting amplifier functions as a

data quantizer for SONET, Fibre-Channel, and Gigabit

Ethernet optical receivers. The amplifier accepts a wide

range of input voltages and provides selectable-level,

current-mode logic (CML) output voltages with con-

trolled edge speeds. A received-signal-strength indica-

tor (RSSI) is available when the MAX3746 is

DC-coupled to the MAX3744/MAX3724 SFP transim-

pedance amplifier (TIA). A receiver consisting of the

MAX3744/MAX3724 and the MAX3746 can provide up

to 19dB RSSI dynamic range. Additional features

include a programmable loss-of-signal (LOS) detect, an

optional disable function (DISABLE), and an

output-signal polarity reversal (OUTPOL). Output dis-

able can be used to implement squelch.

The combination of the MAX3746 and the MAX3744/

MAX3724 allows for the implementation of all the small-

form-factor SFF-8472 digital diagnostic specifications

using a standard 4-pin TO-46 header.

The MAX3746 is pin-for-pin compatible with the

MAX3748A limiting amplifier and consumes 30% less

power. The MAX3746 is packaged in a 3mm x 3mm,

16-pin QFN package.

Applications

Gigabit Ethernet SFF/SFP Transceiver Modules

Fibre-Channel SFF/SFP Transceiver Modules

Multirate OC-12 to OC48-FEC SFF/SFP

Transceiver Modules

Features

♦ SFP Reference Design Available

♦ Low 115mW Power Consumption

♦ 16-Pin QFN Package with 3mm x 3mm Footprint

♦ 70ps Rise and Fall Time

♦ Loss-of-Signal with Programmable Threshold

♦ RSSI Interface (with MAX3744/MAX3724 TIA)

♦ Output Disable

♦ Polarity Select

♦ Improved EMI Performance

♦ Selectable CML Output levels

♦ Pin Compatible with MAX3748A

Low-Power, 622Mbps to 3.2Gbps

Limiting Amplifier

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-3386; Rev 2; 6/07

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-

PACKAGE

PKG CODE

MAX3746ETE

-40°C to +85°C 16 Thin QFN

T1633F-3

MAX3746HETE*

-40°C to +85°C 16 Thin QFN

T1633F-3

Typical Operating Circuits continued at end of data sheet.

Pin Configuration appears at end of data sheet.

*

The MAX3746HETE is a hybrid lead-free package. See the

Detailed Description

section for more information.

MAX3746

MAX3744 TIA

DS1859

3-INPUT DIAGNOSTIC

MONITOR

R1

3k

Ω

C1

0.1

μF

IN+

IN-

RSSI

TH

DISABLE

LOS

OUTPOL

GND

4.7k

Ω TO 10kΩ

LOS

2.97V TO 3.6V

OUT+

50

Ω

0.1

μF

OUT-

50

Ω

0.1

μF

SERDES

Ω

SUPPLY FILTER

HOST FILTER

4-PIN TO HEADER

HOST BOARD

SFP OPTICAL RECEIVER

Typical Operating Circuits