ELECTRICAL SUBASSEMBLY
DATA
DATA
POST
AMPLIFIER IC
PRE-
AMPLIFIER
IC
OPTICAL
SUB-
ASSEMBLIES
LASER
DRIVER
IC
PIN PHOTODIODE
SIGNAL DETECT
DATA
DATA
DUPLEX SC
RECEPTACLE
LASER
Other Members of Agilent SC Duplex
155 Mb/s Product Family
• HFCT-5801, 1300 nm single
mode transceiver for links up
to 15 km. The part is based on
the 2 x 9 industry standard
package and has laser bias,
optical power monitor and
transmitter disable functions.
Applications Information
Typical BER Performance of Receiver
versus Input Optical Power Level
The HFCT-5805 transceiver can
be operated at Bit-Error-Rate
conditions other than the
required BER = 1 x 10
-10
of the
ATM Forum 155.52 Mb/s Physical
Layer Standard. The typical
trade-off of BER versus Relative
Input Optical Power is shown in
Figure 2. The Relative Input
Optical Power in dB is
referenced to the actual
sensitivity of the device. For BER
conditions better than 1 x 10
-10
,
more input signal is needed (+dB).
TOP VIEW
Figure 1. Block Diagram
Transmitter Section
The transmitter section of the
HFCT-5805 consists of a 1300 nm
InGaAsP laser in an eyesafe
optical subassembly (OSA) which
mates to the fiber cable. The laser
OSA is driven by a custom IC
which converts differential input
LVPECL logic signals into an
analog laser drive current.
Receiver Section
The receiver utilizes an InGaAs
PIN photodiode mounted
together with a transimpedance
preamplifier IC in an OSA. This
OSA is connected to a circuit
providing post- amplification
quantization, and optical signal
detection.
Receiver Signal Detect
Signal Detect is a basic fiber
failure indicator. This is a
single-ended LVPECL output. As
the input optical power is
decreased, Signal Detect will
switch from high to low (deassert
point) somewhere between
sensitivity and the no light input
level. As the input optical power
is increased from very low levels,
Signal Detect will switch back
from low to high (assert point).
The assert level will be at least
0.5 dB higher than the deassert
level.
Transceiver Specified for Wide
Temperature Range Operation
The HFCT-5805 is specified for
operation over normal commercial
temperature range of 0° to +70°C
(HFCT-5805B/D) or the extended
temperature range of -40° to
+85°C (HFCT-5805A/C).
Characterization of the parts has
been performed over the ambient
operating temperature range in
an airflow of 2 m/s.
2
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
