MAX3946_10 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

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MAX3946_10

1.0625Gbps to 11.3Gbps, SFP+ Laser Driver with Laser Impedance Mismatch Tolerance

Maxim Integrated 

19-5182; Rev 0; 3/10

EVAALVUAAILTAIOBNLEKIT

1.0625Gbps to 11.3Gbps, SFP+ Laser Driver

with Laser Impedance Mismatch Tolerance

General Description

The MAX3946 is a +3.3V, multirate, low-power laser

diode driver designed for Ethernet and Fibre Channel

transmission systems at data rates up to 11.3Gbps.

This device is optimized to drive a differential transmit-

ter optical subassembly (TOSA) with a 25I flex circuit.

The unique design of the output stage enables use of

unmatched TOSAs, greatly reducing headroom limita-

tions and lowering power consumption.

The device receives differential CML-compatible signals

with on-chip line termination. It can deliver laser modula-

tion current of up to 80mA, at an edge speed of 20ps

(20% to 80%), into a 5I to 25I external differential load.

The device is designed to have a symmetrical output

stage with on-chip back terminations integrated into

its outputs. A high-bandwidth, fully differential signal

path is implemented to minimize deterministic jitter. An

equalization block can be activated to compensate for

the SFP+ connector. The integrated bias circuit provides

programmable laser bias current up to 80mA. Both the

laser bias generator and the laser modulator can be dis-

abled from a single pin, DISABLE.

A 3-wire digital interface reduces the pin count and

permits adjustment of input equalization, pulse-width

adjustment, Tx polarity, Tx deemphasis, modulation cur-

rent, and bias current without the need for external com-

ponents. The MAX3946 is available in a 4mm x 4mm,

24-pin TQFN package.

Applications

4x/8x FC SFP+ Optical Transceivers

10GFC SFP+ Optical Transceivers

10GBASE-LR SFP+ Optical Transceivers

10GBASE-LRM SFP+ Optical Transceivers

OC192-SR XFP/SFP+ Transceivers

Features

S 225mW Power Dissipation Enables < 1W SFP+

Modules

S Up to 100mW Power Consumption Reduction by

Enabling the Use of Unmatched FP/DFB TOSAs

S Supports SFF-8431 SFP+ MSA and SFF-8472

Digital Diagnostic

S 225mW Power Dissipation at 3.3V (IMOD = 40mA,

IBIAS = 60mA Assuming 25I TOSA)

S Single +3.3V Power Supply

S Up to 11.3Gbps (NRZ) Operation

S Programmable Modulation Current from 10mA to

100mA (5I Load)

S Programmable Bias Current from 5mA to 80mA

S Programmable Input Equalization

S Programmable Output Deemphasis

S 25I Output Back Termination at TOUT+ and

TOUT-

S DJ Performance 7psP-P with Mismatched

Differential Load (5I)

S DJ Performance 5psP-P with Mismatched

Differential Load (25I)

S DJ Performance 5psP-P with 50I Differential Load

S Programmable Pulse Width

S Edge Transition Times of 20ps

S Bias Current Monitor

S Integrated Eye Safety Features

S 3-Wire Digital Interface

S -40°C to +95°C Operation

Ordering Information

PART

TEMP RANGE

PIN-PACKAGE

MAX3946ETG+

-40°C to +85°C

24 TQFN-EP*

Note: Parts are guaranteed by design and characterization to

operate over the -40°C to +95°C ambient temperature range

(TA) and are tested up to +85°C.

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

________________________________________________________________ Maxim Integrated Products   1

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.

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