3.3 Volt Laser Driver IC for Applications to 3 Gbps
Safety logic is provided in order to limit the maximum
bias current. The bias current at which the safety
logic trips is set by an external resistor to ground
(ROCA) from the OCASET pin. When the bias current
limit is reached alarm flag OCA is asserted LOW. A
loop failure alarm is also provided to detect when the
bias current can no longer be adjusted to achieve the
desired average optical power.
Data Input Latch
To minimize input data pattern-dependent jitter, a
differential clock signal can be connected to the data
input latch. If CEN is HIGH, the input data is retimed
by the rising edge of CLK+. If CEN is LOW, the input
data is directly connected to the output stage. If
CEN is left floading it will be pulled HIGH by the internal
circuitry. When this latch function is not used, connect
CLK+ to VCC and leave CLK- unconnected.
The CX02066 incorporates a dual laser driver enable
function. When ENA is LOW or DIS is HIGH, both the
bias and modulation currents are off. Only DIS is
available on the BCC package.
The CX02066 features bias and modulation current
monitor outputs. The BIASMON output sinks a current
equal to nominally 1/55 of the laser bias current (IBIAS).
The MODMON output sinks a current equal to
nominally 1/55 of the laser peak to peak modulation
current (IMOD). BIASMON and MODMON should be
connected through a pull-up resistor to VCC. Choose
a pull-up resistor value that ensures a voltage at
BIASMON greater than VCC - 1.6V and a voltage at
MODMON greater than VCC - 1.0V. These pins should
be tied to VCC if not used.
For laser safety and reliability, the CX02066
incorporates a slow-start circuit that provides a delay
of approximately 200ns before enabling the laser
TYPICAL EYE DIAGRAM
2.5Gbps Optical Eye @ -3dBm
ADVANCED INFORMATION - REV FF