General Description

The MAX3643 burst-mode laser driver provides bias

and modulation current drive for PON burst-mode ONT

applications. It is specifically designed for use with a

low-cost external controller for the APC (and if desired,

AMC) loop. A high-speed differential burst-enable input

enables the driver to switch the laser from a dark (out-

put off) condition to full on-condition in less than 2ns.

When BEN is inactive, typical modulation and bias cur-

rents are 5µA each.

Laser modulation current can be set from 10mA to 85mA

and bias current can be set from 1mA to 70mA using the

MODSET and BIASSET inputs. A sample-and-hold circuit

is provided to capture the monitor diode output during

short PON bursts, if needed, and the BEN high-speed

signal is mirrored on an LVCMOS output to be used by

the controller operating the APC/AMC loop.

The MAX3643 burst-mode laser driver is packaged in a

4mm x 4mm, 24-pin thin QFN package. It operates from

-40°C to +85°C.

Applications

A/B/GPON ONT Modules up to 2.5Gbps

1.25Gbps IEEE EPON ONT Modules

Features

♦ 10mA to 85mA Modulation Current

♦ 1mA to 70mA Bias Current

♦ Monitor Diode Sample and Hold

♦ 45ps Output Transition Time

♦ 2ns Turn-On/-Off Time

♦ Reference Voltage Generator

♦ LVPECL High-Speed Inputs (Data, Burst Enable)

155Mbps to 2.5Gbps Burst-Mode Laser Driver

________________________________________________________________

Maxim Integrated Products

1

PART

TEMP RANGE

PIN-PACKAGE

MAX3643ETG

-40°C to +85°C

24 TQFN-EP*

MAX3643ETG+

-40°C to +85°C

24 TQFN-EP*

Ordering Information

OUT-

FILTER

+3.3V

OUT+

10

Ω

15

Ω

+3.3V

0.1

μF

24

Ω

27nH

10

Ω

BIAS+

15

Ω

START CONVERT

ANALOG OUT

ANALOG OUT

ANALOG IN

ANALOG IN

ANALOG IN

CONTINUOUS

OPERATION

CONTROLLER

1k

Ω

BIAS-

MDIN

MDOUT

GND

BENOUT

BIASSET

MODSET

VBSET

VMSET

3k

Ω

1k

Ω

1k

Ω

1k

Ω

BCMON

IMAX

EN

VREF

BEN-

BEN+

IN-

IN+

CONTROL

MAX3643

Typical Application Circuit

19-3848; Rev 1; 10/08

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.

EVALUATION

KIT

AVAILABLE

+

Denotes a lead-free/RoHS-compliant package.

*

EP = Exposed paddle.

Pin Configuration appears at end of data sheet.