HFCT-5205
SC Duplex Single Mode Transceiver
Part of the Avago METRAK family
Data Sheet
Description
The HFCT-5205 transceiver is a high performance, cost
effective module for serial optical data communications
applications specified for a signal rate of 155 MBd. It is
designed to provide a SONET/SDH compliant link for 155
Mb/s intermediate reach links.
This module is designed for single mode fiber and
operates at a nominal wavelength of 1300 nm. It incorpo-
rates Avago’s high performance, reliable, long wavelength
optical devices and proven circuit technology to give long
life and consistent service.
The transmitter section uses a Multiple Quantum Well
laser with full IEC 825 and CDRH Class I eye safety.
The receiver section uses a planar PIN photodetector for
low dark current and excellent responsivity.
A pseudo-ECL logic interface simplifies interface to
external circuitry.
Features
•
SC duplex single mode transceiver
•
Intermediate SONET OC3 SDH STM1 (S1.1) compliant
•
Single +5 V power supply
•
Multisourced 1 x 9 pin configuration
•
Aqueous washable plastic package
•
Interchangeable with LED multisourced 1 x 9 trans-
ceivers
•
Unconditionally eye safe laser IEC 825/CDRH Class 1
compliant
•
Two temperature ranges:
0° C to +70° C – HFCT-5205B/D
-40° C to +85° C – HFCT-5205A/C
Applications
•
SONET/SDH equipment interconnect
•
ATM 155 Mb/s links
Connection Diagram
RECEIVER SIGNAL GROUND
o
1
RECEIVER DATA OUT
o
2
RECEIVER DATA OUT BAR
o
3
SIGNAL DETECT
o
4
RECEIVER POWER SUPPLY
o
5
TRANSMITTER POWER SUPPLY
o
6
TRANSMITTER DATA IN BAR
o
7
TRANSMITTER DATA IN
o
8
TRANSMITTER SIGNAL GROUND
o
9
N/C
N/C
Top View
Pin Descriptions:
Pin 1 Receiver Signal Ground V
EER
:
Directly connect this pin to the receiver ground plane.
Pin 6 Transmitter Power Supply V
CCT
:
Provide +5 V DC via the recommended transmitter power
supply filter circuit. Locate the power supply filter circuit
as close as possible to the V
CC
pin.
Pin 2 Receiver Data Out RD:
See recommended circuit schematic, Figure 4.
Pin 3 Receiver Data Out Bar RD:
See recommended circuit schematic, Figure 4.
Pin 7 Transmitter Data In Bar TD:
See recommended circuit schematic, Figure 4.
Pin 4 Signal Detect SD:
Normal optical input levels to the receiver result in a logic
“1” output.
Low optical input levels to the receiver result in a fault
condition indicated by a logic “0” output.
This Signal Detect output can be used to drive a PECL
input on an upstream circuit, such as Signal Detect input
or Loss of Signal-bar.
Pin 8 Transmitter Data In TD:
See recommended circuit schematic, Figure 4.
Pin 9 Transmitter Signal Ground V
EET
:
Directly connect this pin to the transmitter ground plane.
Mounting Studs
The mounting studs are provided for mechanical attach-
ment to the circuit board. They are embedded in the
nonconductive plastic housing and are not tied to the
transceiver internal circuit and should be soldered into
plated-through holes on the printed circuit board.
Pin 5 Receiver Power Supply V
CCR
:
Provide +5 V DC via the recommended transmitter power
supply filter circuit. Locate the power supply filter circuit
as close as possible to the V
CC
pin.
2
Functional Description – Receiver Section
Design
The receiver section contains an InGaAs/InP photo
detector and a preamplifier within the receptacle, coupled
to a postamp/decision circuit on a separate circuit board.
The postamplifier is AC coupled to the preamplifier as
illustrated in Figure 1. The coupling capacitor is large
enough to pass the SONET/SDH test pattern at 155 MBd
without significant distortion or performance penalty. If
a lower signal rate, or a code which has significantly more
low frequency content is used, sensitivity, jitter and pulse
distortion could be degraded.
Figure 1 also shows a filter network which limits the
bandwidth of the preamp output signal. The filter is
designed to bandlimit the preamp output noise and thus
improve the receiver sensitivity.
These components will also reduce the sensitivity of the
receiver as the signal bit rate is increased above 155 MBd.
Terminating the Outputs
The PECL Data outputs of the receiver may be terminated
with the standard Thevenin-equivalent 50 ohm to V
CC
–
2 V termination. Other standard PECL terminating tech-
niques may be used.
The two outputs of the receiver should be terminated
with identical load circuits to avoid unnecessarily large
AC current in V
CC
. If the outputs are loaded identically the
AC current is largely nulled. The Signal Detect output of
the receiver is PECL logic and must be loaded if it is to be
used. The Signal Detect circuit is much slower than the
data path, so the AC noise generated by an asymmetrical
load is negligible. Power consumption may be reduced by
using a higher than normal load impedance for the Signal
Detect output. Transmission line effects are not generally
a problem as the switching rate is slow.
The Signal Detect Circuit
The Signal Detect circuit works by sensing the peak
level of the received signal and comparing this level to a
reference.
Noise Immunity
The receiver includes internal circuit components to filter
power supply noise. Under some conditions of EMI and
power supply noise, external power supply filtering may
be necessary. If receiver sensitivity is found to be degraded
by power supply noise, the filter network illustrated in
Figure 2 may be used to improve performance. The values
of the filter components are general recommendations
and may be changed to suit a particular system environ-
ment. Shielded inductors are recommended.
TRANS-
IMPEDANCE
PRE-
AMPLIFIER
RECEIVER
RECEPTACLE
FILTER
LIMITING
AMPLIFIER
DATA OUT
PECL
OUTPUT
BUFFER
DATA OUT
GND
SIGNAL
DETECT
CIRCUIT
PECL
OUTPUT
BUFFER
SD
Figure 1. Receiver Block Diagram
V
CC
100 nF
3.3 µH
100 nF
FILTERED V
CC
to DATA LINK
+
10 µF
Figure 2 .
π
Filter Network for Noise Filtering
3
Functional Description – Transmitter Section
Design
The transmitter section, Figure 3, uses a Multiple Quantum
Well laser as its optical source. The package of this laser is
designed to allow repeatable coupling into single mode
fiber. In addition, this package has been designed to be
compliant with IEC 825 Class 1 and CDRH Class I eye safety
requirements. The optical output is controlled by a custom
IC which detects the laser output via the monitor photo-
diode. 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 life.
PCB mounting
The HFCT-5205 has two solderable mounting studs,
Figures 5 and 6. These studs are not electrically connected.
The transceiver is designed for common production
processes. It may be wave soldered and aqueous washed
providing the process plug is in place.
Each process plug can only be used once during process-
ing, although with subsequent use, it can be used as a
dust cover.
LASER
PHOTODIODE
(rear facet monitor)
DATA
DATA
PECL
INPUT
LASER
MODULATOR
LASER BIAS
DRIVER
LASER BIAS
CONTROL
Figure 3. Simplified Transmitter Schematic
4
NO INTERNAL
CONNECTION
TOP VIEW
NO INTERNAL
CONNECTION
V
EER
1
RD
2
RD
3
SD
4
V
CCR
5
V
CCT
6
TD
7
TD
8
V
EET
9
C1 C7
L1
R7
C6
R8
R10
C3
C8 C2
V
CC
L2
C4
R1
R2
R3
C5
R4
NOTES:
THE SPLIT-LOAD TERMINATIONS FOR ECL SIGNALS
NEED TO BE LOCATED AT THE INPUT OF DEVICES
RECEIVING THOSE ECL SIGNALS. RECOMMEND
4-LAYER PRINTED CIRCUIT BOARD WITH 50 W
MICROSTRIP SIGNAL PATHS BE USED.
R1 = R4 = R6 = R8 = R10 = 130 W
R2 = R3 = R5 = R7 = R9 = 82 W
C1 = C2 = 10 µF (see Figure 2)
C3 = C4 = C7 = C8 = 100 nF
C5 = C6 = 0.1 µF
L1 = L2 = 3.3 µH COIL OR FERRITE INDUCTOR.
V
CC
TERMINATE
AT THE
DEVICE
INPUTS
R6
R5
V
cc
FILTER
AT V
cc
PINS
TRANSCEIVER
R9
TERMINATION
AT
TRANSCEIVER
INPUTS
TD
TD
RD
RD
SD
V
CC
Figure 4. Recommended Circuit Schematic
Regulatory Compliance
Feature
Electrostatic Discharge
(ESD) to the Electrical Pins
Electrostatic Discharge (ESD)
to the Duplex SC Receptacle
Electromagnetic
Interference (EMI)
Test Method
MIL-STD-883C
Method 3015.4
Variation of IEC 801-2
Targeted Performance
Class 1 (>1 kV) – Human Body Model
Products of this type, typically, withstand at least 25 kV without
damage when the Duplex MT-RJ Connector Receptacle is
contacted by a Human Body Model probe.
Typically provide a 17 dB margin to the noted standard limits
up to 6 GHz, when tested in a GTEM cell with the transceiver
mounted to a circuit card with a chassis enclosure.
Typically show no measurable effect from a 10 V/m field swept
from 27 MHz to 1 GHz applied to the transceiver without a chassis
enclosure.
CDRH Accession Number: 9521220-26
TUV Bauart License: 933/510018/02
FCC Class B
CENELEC EN55022 Class B
(CISPR 22A)
VCCI Class 1
Variation of IEC 801-3
Immunity
Eye Safety
FDA CDRH 21-CFR 1040
Class I
IEC 825 Issue 1 1993:11
Class 1
CENELEC EN60825 Class 1
5
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