11.3 Gbps Active Back-Termination,
Differential Laser Diode Driver
Data Sheet
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FEATURES
3.3 V operation
Up to 11.3 Gbps operation
Typical 24 ps rise/fall times
Full back-termination of output transmission lines
Drives TOSAs with resistances ranging from 5 Ω to 50 Ω
Bias current range: 10 mA to 100 mA
Differential modulation current range: 10 mA to 80 mA
Voltage input control for bias and modulation currents
Data inputs sensitivity: 150 mV p-p diff
Automatic laser shutdown (ALS)
Cross point adjustment (CPA)
XFP-compliant bias current monitor
SFP+ MSA compliant
Optical evaluation board available
Compact 3 mm × 3 mm LFCSP
APPLICATIONS
SONET OC-192 and SDH STM-64 optical transceivers
10 Gb Fibre Channel transceivers
10 Gb Ethernet optical transceivers
SFP+/XFP/X2/XENPAK/XPAK/MSA 300 optical modules
GENERAL DESCRIPTION
The ADN2526 laser diode driver is designed for direct modula-
tion of packaged laser diodes that have a differential resistance
ranging from 5 Ω to 50 Ω. The active back-termination in the
ADN2526 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. ADN2526 is an SFP+ MSA-
compliant device, and its small package and enhanced ESD
protection provide 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 optical power and extinction ratio control schemes,
including closed-loop or look-up table control. The automatic
laser shutdown (ALS) feature allows the user to turn on/off the
bias and modulation currents by driving the ALS pin with a
LVTTL logic source.
The product is available in a space-saving 3 mm × 3 mm LFCSP
specified from −40°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM
50Ω
200Ω
800Ω
200Ω 2Ω
VCC
DATAP
DATAN
MSET VEE BSET
IBMON
IBIAS
IMODP
IMODN
ADN2526
VCC
ALS
VCC
CPA
GND
VCC
50Ω
50Ω
200Ω
800Ω
IMOD
CROSS
POINT
ADJUST
07511-001
Figure 1.
