MAX3850 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 2.7Gbps, +3.3V DC-Coupled Laser Driver

19-2294; Rev 1; 5/03
EVAALVUAAILTAIOBNLEKIT
2.7Gbps, +3.3V DC-Coupled
Laser Driver
General Description
The MAX3850 is a +3.3V DC-coupled laser driver for
SDH/SONET applications up to 2.7Gbps. The device
accepts differential data and clock inputs and provides
bias and modulation currents for driving a laser. If a
clock signal is available, a synchronizing input latch
can be used to reduce jitter. An automatic power-con-
trol (APC) feedback loop is incorporated to maintain a
constant average optical power over temperature and
lifetime. The wide modulation current range of 5mA to
60mA (up to 80mA AC-coupled) and bias current of
1mA to 100mA are easy to program, making this prod-
uct ideal for SDH/SONET applications. The MAX3850
also provides laser current-enable control, two current
monitors that are directly proportional to the laser bias
and modulation currents, and a failure-monitor output to
indicate when the APC loop is unable to maintain the
average optical power. Designed to be DC-coupled to
the laser with a supply voltage of only 3.3V, the
MAX3850 greatly simplifies interface requirements. The
MAX3850 is available in a small 32-pin QFN package
as well as dice.
Applications
SDH/SONET Transmission
Systems
MPLS Transmitter Systems
Add/Drop Multiplexers
Digital Cross-Connects
Section Regenerators
Features
♦ Single +3.3V Power Supply
♦ 35mA Supply Current
♦ Programmable Bias Current from 1mA to 100mA
♦ Programmable Modulation Current from 5mA to
60mA (Up to 80mA AC-Coupled)
♦ Bias Current and Modulation Current Monitors
♦ 70ps Rise/Fall Time
♦ Automatic Average Power Control with Failure
Monitor
♦ Complies with ANSI, ITU, and Bellcore
SDH/SONET Specifications
♦ Laser Current-Enable Control
Ordering Information
PART
TEMP
RANGE
PIN-
PACKAGE
PACKAGE
CODE
MAX3850EGJ -40°C to +85°C 32 QFN
MAX3850E/D -40°C to +85°C Dice*
G3255-1
—
*Dice are designed to operate over this range, but are tested
and guaranteed at T_A = +25°C only. Contact factory for
availability.
Typical Application Circuits are continued at the end of the
data sheet.
Pin Configuration appears at the end of the data sheet.
Typical Application Circuits
MAX3890
SERIALIZER
WITH
CLOCK GEN
100Ω
100Ω
TYPICAL APPLICATION CIRCUIT
WITH DC-COUPLED INPUTS
3.3V 3.3V
0.01µF
LD
DATA+
16Ω
VCC
DATA-
CLOCK+
MAX3850
OUT-
OUT+
11Ω
50Ω
8.0pF
CLOCK-
BIAS
MD
BIASMON
MODMON
0.1µF 0.1µF _{392Ω 392Ω}
3.3V
1000pF
Covered by U.S. Patent numbers 5,802,089 and 5,883,910
________________________________________________________________ Maxim Integrated Products 1
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