3.3 V Dual-Loop, 50 Mbps to 3.3 Gbps
Laser Diode Driver
SFP/SFF and SFF-8472 MSA compliant
SFP reference design available
Any rate from 50 Mbps to 3.3 Gbps operation
Dual-loop control of average power and extinction ratio
Typical rise/fall time: 60 ps
Bias current range: 2 mA to 100 mA
Modulation current range: 5 mA to 90 mA
Laser FAIL alarm and automatic laser shutdown (ALS)
Bias and modulation current monitoring
3.3 V operation
4 mm × 4 mm LFCSP
Voltage setpoint control
Resistor setpoint control
Multirate OC3 to OC48-FEC SFP/SFF modules
1×/2×/4× Fibre Channel SFP/SFF modules
DWDM/CWDM SFP modules
1GE SFP/SFF transceiver modules
Like the ADN2870, the ADN28721 laser diode driver is designed
for advanced SFP and SFF modules, using SFF-8472 digital
diagnostics. The device features dual-loop control of the average
power and extinction ratio, which automatically compensates
for variations in laser characteristics over temperature and aging.
The laser needs only be calibrated at 25°C, eliminating the need
for expensive and time consuming temperature calibration. The
ADN2872 supports single-rate operation from 50 Mbps to
3.3 Gbps, or multirate operation from 155 Mbps to 3.3 Gbps.
With a new alarm scheme, this device avoids the shutdown issue
caused by the system transient generated from various lasers.
The average power and extinction ratio can be set with a
voltage provided by a microcontroller DAC or by a trimmable
resistor. The part provides both bias and modulation current
monitoring, as well as fail alarms and automatic laser shutdown.
The ADN2872, a SFF-/SFP-compliant laser diode driver, can
work with the Analog Devices, Inc., ADuC7019/ADuC702x
MicroConverter® family and the ADN289x limiting amplifier
family, to form a complete SFP/SFF transceiver solution. The
ADN2872 is available in a space-saving 4 mm × 4 mm LFCSP
specified over the −40°C to +85°C temperature range.
Figure 1 shows an application diagram with a microcontroller
1 Protected by U.S. Patent 6,414,974.
IBMON IMMON PAVCAP ERCAP
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
©2009 Analog Devices, Inc. All rights reserved.