02066-BRF-001-A Datasheet, PDF (1/2 Pages) M/A-COM Technology Solutions, Inc. – 3 Gbps Laser Driver

™
A CONEXANT BUSINESS
3 Gbps Laser Driver
CX02066
3.3 Volt Highly Integrated, Programmable
Laser Driver IC for SONET/SDH Applications
Mindspeed Technologies’^™ 3 Gbps laser driver delivers
industry-leading power-consumption figures in small
form-factor BCC packages. Ideal for datacom and
telecom modules, it enables a progression path into
OC-48 applications with a low external component count.
The CX02066 is a highly integrated, programmable laser
driver intended for short-reach SONET/SDH applications
with forward error correction (FEC). The versatile
CX02066 can be used in lower data-rate access rings
(OC-12 and lower), as well as in metro link add/drop
multiplexers operating at OC-48.
Using differential PECL data and clock inputs, the
CX02066 supplies the bias and modulation current for
driving an edge-emitting laser. The modulation output
can be DC-coupled to the laser diode, giving a significant
power savings over AC-coupled operation.
The CX02066 includes automatic power control (APC) to
maintain a constant average laser output power over
temperature and life. In addition, the modulation current
is temperature-compensated to minimize variation in
extinction ratio over temperature. Output flags indicate
laser end-of-life as well as failure of the APC circuitry
to maintain average output power.
The CX02066 laser driver consists of a high-speed
modulation driver and a laser bias generator with mean
power control (MPC). It is optimized for high-speed,
> KEY FEATURES
> High-speed operation;
suitable for applications
up to 3 Gbps
> Differential data and
clock inputs minimize
pattern-dependent jitter
> DC- or AC-coupled
modulation drive consumes
significantly less power
than competing solutions
at 3.3 volts
> Minimal external
component count
> Bias and modulation
current monitor
> Automatic laser power
control, with programmable
temperature compensation
and ‘slow-start’
low-power operation with a 3.3 V supply. To minimize the
pattern-dependent jitter of the input signal, the device
accepts an input clock signal for data retiming.
To maintain constant average optical power, the
CX02066 incorporates a control loop to compensate
for the changes in laser threshold current over
temperature and lifetime.
The modulator output stage is designed to drive up to
85 mA into a 25 Ω load, in AC-coupled or DC-coupled
mode. The DC-coupled mode significantly reduces power
consumption. Unlike many competing devices, the CX02066
is capable of operating in this mode at 3.3 V, further
reducing power consumption.
A monitor photodiode mounted in the laser package is
used to convert the optical power into a photocurrent.
The MPC loop adjusts the laser bias current so that the
voltage at PD is matched to an on-chip reference voltage.
>