11.3 Gbps, Active Back-Termination,

Differential VCSEL Driver

ADN2530

Rev. A

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FEATURES

Up to 11.3 Gbps operation

−40°C to +100°C operation

Typical 26 ps rise/fall times

Full back-termination of output transmission lines

Crosspoint adjust function

PECL-/CML-compatible data inputs

Bias current range: 2 mA to 25 mA

Differential modulation current range: 2.2 mA to 23 mA

Automatic laser shutdown (ALS)

3.3 V operation

Compact 3 mm × 3 mm LFCSP

Voltage-input control for bias and modulation currents

XFP-compliant bias current monitor

APPLICATIONS

10 Gb Ethernet optical transceivers

10G-BASE-LRM optical transceivers

8× and 10× Fibre Channel optical transceivers

XFP/X2/XENPAK/MSA 300 optical modules

SONET OC-192/SDH STM-64 optical transceivers

GENERAL DESCRIPTION

The ADN2530 laser diode driver is designed for direct modula-

tion of packaged VCSELs with a differential resistance ranging

from 35 Ω to 140 Ω. The active back-termination technique

provides excellent matching with the output transmission lines

while reducing the power dissipation in the output stage. The

back-termination in the ADN2530 absorbs signal reflections

from the TOSA end of the output transmission lines, enabling

excellent optical eye quality to be achieved even when the

TOSA end of the output transmission lines is significantly

misterminated. The small package provides the optimum

solution for compact modules where laser diodes are packaged

in low pin count optical subassemblies.

The modulation and bias currents are programmable via the

MSET and BSET control pins. By driving these pins with

control voltages, the user has the flexibility to implement

various average power and extinction ratio control schemes,

including closed-loop control and look-up tables. The eye

crosspoint in the output eye diagram is adjustable via the

crosspoint adjust (CPA) control voltage input. The automatic

laser shutdown (ALS) feature allows the user to turn on/off the

bias and modulation currents by driving the ALS pin with the

proper logic levels. The product is available in a space-saving

3 mm × 3 mm LFCSP specified from −40°C to +100°C.

FUNCTIONAL BLOCK DIAGRAM

100Ω

200Ω

800Ω

200Ω

10Ω

VCC

DATAP

DATAN

MSET

GND

BSET

IBMON

IBIAS

IMODP

IMODN

ADN2530

VCC

ALS

GND

VCC

VCC

50Ω

50Ω

CPA

200Ω

800Ω

CROSS

POINT

ADJUST

IMOD

Figure 1.