HFCT5745P Avago Technologies US Inc., HFCT5745P Datasheet - Page 2

• Manufacturer Part Number: HFCT5745P
• Manufacturer: Avago Technologies US Inc.

Specifications of HFCT5745P

• Optical Fiber Type: TX/RX
• Data Transfer Rate: 2700Mbps
• Optical Rise Time: 0.15ns
• Optical Fall Time: 0.2ns
• Operating Temperature Classification: Commercial
• Peak Wavelength: 1360/1580nm
• Package Type: SFP
• Operating Supply Voltage (min): 3.1V
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.5V
• Operating Temp Range: -10C to 85C
• Mounting: Snap Fit To Panel
• Pin Count: 20
• Lead Free Status / Rohs Status: Not Compliant

Functional Description
Receiver Section Design
The receiver section for the
HFCT-5745xx contains an
InGaAs/InP photo detector and
a preamplifier mounted in an
optical subassembly. This
optical subassembly is coupled
to a postamplifier/decision
circuit on a circuit board. The
postamplifier is ac coupled to
the preamplifier. The coupling
capacitors are chosen to pass
the SONET/SDH test pattern at
155 Mb/s, 622 Mb/s and 2.488
Gb/s without significant
distortion or performance
penalty.
For multirate applications the
sensitivity will meet the
maximum SONET specification
for OC48 across all datarates
(-19dBm) for 2
patterns as well as for dc
balanced codes, e.g. 8B/10B.
For codes that have a
significantly lower frequency
content, jitter and pulse
distortion could be degraded.
Loss of Signal
The Loss of Signal (LOS)
output indicates that the
optical input signal to the
receiver does not meet the
minimum detectable level for
compliant signals. When LOS is
high it indicates loss of signal.
When LOS is low it indicates
normal operation. The Loss of
Signal thresholds are set to
indicate a definite optical fault
has occurred (eg., disconnected
or broken fiber connection to
receiver, failed transmitter).
2
23
-1 PRBS
Transmitter Section Design
A schematic diagram for the
transmitter is shown in Figure
1. The HFCT-5745L
incorporates an FP laser as its
optical source, the HFCT-
5745TL incorporates an DFB
laser as its optical source. All
part numbers have been
designed to be compliant with
IEC 825 and CDRH eye safety
requirements. The optical
output is controlled by a
custom IC that detects the
laser output via the monitor
photodiode. This IC provides
both dc and ac current drive
to the laser to ensure correct
modulation, eye diagram and
extinction ratio over
temperature, supply voltage
and operating life.
TX_FAULT
The HFCT-5745xx modules
feature a transmit fault control
signal output which when high
indicates a laser transmit fault
has occurred and when low
indicates normal laser
operation. A transmitter fault
condition can be caused by
deviations from the
recommended module
operating conditions or by
violation of eye safety
conditions. A fault is cleared
by cycling the TX_DISABLE
control input.
TX_DISABLE
The HFCT-5745xx accepts a
transmit disable control signal
input which shuts down the
transmitter. A high signal
implements this function while
a low signal allows normal
laser operation. In the event of
a fault (eg., eye safety circuit
activated), cycling this control
signal resets the module. The
TX_DISABLE control should be
actuated upon initialization of
the module.
Digital Diagnostic Interface and
Serial Identification (EEPROM)
The HFCT-5745xx complies
with both SFF-8074i (SFP) and
SFF-8472 (Digital Diagnostic
SFP) specifications available
from the SFF Committee at
http://www.sffcommittee.org.
The HFCT-5745xx adds digital
diagnostic monitoring to
standard SFP functionality,
enabling failure prediction,
fault islolation, and component
monitoring capabilities. The
transceiver continues to use
the 2-wire serial CMOS
EEPROM protocol of the
ATMEL AT24C01A or
equivalent. Standard SFP
EEPROM bytes 0-255 are
addressed per SFF-8074i at
memory address 0xA0 (A0h).
New digital diagnostic
information is accessed per
SFF-8472 using EEPROM bytes
0-255 at memory address 0xA2
(A2h).
The HFCT-5745xx provides
real time access to transceiver
internal supply voltage and
temperature, transmitter
output power, laser bias
current and receiver average
input power, allowing a host
to predict system compliance
issues.
These 5 parameters are
reported "internally" calibrated
as described in SFF-8472.