AFCT-5962TLZ/TGZ/ATLZ/ATGZ/NLZ/NGZ
Single Mode Laser Small Form Factor Transceivers for
ATM, SONET OC-3 /SDH STM-1
Part of the Avago Technologies METRAK family
Data Sheet
Description
The AFCT-5962TLZ/TGZ/ATLZ/ATGZ/NLZ/NGZ are high per-
formance, cost effective modules for serial optical data
communications applications specified for a signal rate
of 155 Mb/s. They are designed to provide SONET/SDH
compliant intermediate and long reach links at 155 Mb/s.
All modules are designed for single mode fiber and
operate at a nominal wavelength of 1300 nm. They in-
corporate high performance, reliable, long wavelength
optical devices and proven circuit technology to give long
life and consistent service.
The transmitter section of the AFCT-5962TLZ/TGZ/ATLZ/
ATGZ/NLZ/NGZ incorporates a 1300 nm Fabry Perot (FP)
laser.
The transmitter has full IEC 825 and CDRH Class 1 eye
safety.
The receiver section uses an MOVPE grown planar PIN pho-
todetector for low dark current and excellent responsivity.
A pseudo-ECL compatible logic interface simplifies inter-
face to external circuitry.
These transceivers are supplied in the new industry
standard 2 x 10 DIP style package with the LC fiber con-
nector interface and is footprint compatible with SFF Multi
Source Agreement (MSA).
Features
•
RoHS Compliant
•
AFCT-5962TLZ/ATLZ:
Links of 15 km with 9/125
µm
single mode fiber (S1.1)
•
AFCT-5962NLZ:
Links of 40 km with 9/125
µm
single mode fiber (L1.1)
•
Multisourced 2 x 10 package style with LC receptacle
•
Single +3.3 V power supply
•
Temperature range:
AFCT-5962TLZ: 0° C to +70° C
AFCT-5962ATLZ: -40° C to +85° C
AFCT-5962NLZ: -5° C to +70° C
•
Wave solder and aqueous wash process compatible
•
Manufactured in an ISO9002 certified facility
•
Fully Class 1 CDRH/IEC 825 compliant
•
LVPECL compatible signal detect output
•
Transceivers are available with and without EMI nose
shield (see ordering information details)
Applications
•
SONET/SDH equipment interconnect, OC-3/SDH STM-1
rate
•
Long and intermediate reach ATM/SONET links
•
Suitable for Fast Ethernet Applications
Functional Description
Receiver Section
Design
The receiver section for the AFCT-5962TLZ/TGZ/ATLZ/
ATGZ/NLZ/NGZ contains an InGaAs/InP photo detector
and a preamplifier mounted in an optical subassembly.
This optical subassembly is coupled to a postamp/decision
circuit on a circuit board. The design of the optical
assembly is such that it provides better than 14 dB Optical
Return Loss (ORL).
The postamplifier is ac coupled to the preamplifier as
illustrated in Figure 1. The coupling capacitors are large
enough to pass the SONET/SDH test pattern at 155 Mb/s
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 function 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 reduce the sensitivity of the
receiver as the signal bit rate is increased above 155 Mb/s.
The device incorporates a photodetector bias circuit. This
output must be connected to V
CC
and can be monitored
by connecting through a series resistor (see Application
Section).
Noise Immunity
The receiver includes internal circuit components to filter
power supply noise. However under some conditions
of EMI and power supply noise, external power supply
filtering may be necessary (see Application Section).
The Signal Detect Circuit
The signal detect circuit works by sensing the level of the
received signal and comparing this level to a reference.
The SD output is low voltage PECL.
PHOTODETECTOR
BIAS
TRANS-
IMPEDANCE
PRE-
AMPLIFIER
FILTER
AMPLIFIER
DATA OUT
LVPECL
OUTPUT
BUFFER
DATA OUT
GND
SIGNAL
DETECT
CIRCUIT
LVPECL
OUTPUT
BUFFER
SD
Figure 1. Receiver Block Diagram
2
Functional Description
Transmitter Section
Design
A schematic diagram for the transmitter is shown in
Figure 2. The AFCT-5962TLZ/TGZ/ATLZ/ATGZ/NLZ/NGZ
incorporates an FP laser as its optical source. All part
numbers have been designed to be compliant with IEC 825
eye safety requirements under any single fault condition
and CDRH under normal operating conditions. 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 tem-
perature, supply voltage and operating life.
The transmitter also includes monitor circuitry for both
the laser diode bias current and laser diode optical power.
FP
LASER
PHOTODIODE
(rear facet monitor)
DATA
DATA
LVPECL
INPUT
LASER
MODULATOR
B
MON
(+)
B
MON
(-)
LASER BIAS
DRIVER
P
MON
(+)
P
MON
(-)
LASER BIAS
CONTROL
Figure 2. Simplified Transmitter Schematic
3
Package
The overall package concept for these devices consists of
the following basic elements; two optical subassemblies,
a electrical subassembly and the housing as illustrated in
the block diagram in Figure 3.
The package outline drawing and pin out are shown in
Figures 4 and 5. The details of this package outline and pin
out are compliant with the multisource definition of the
2 x 10 DIP. The low profile of the Avago transceiver design
complies with the maximum height allowed for the LC
connector over the entire length of the package.
The electrical subassembly consists of a high volume mul-
tilayer printed circuit board on which the IC and various
surface-mounted passive circuit elements are attached.
The optical subassemblies are attached to the electrical
subassembly. These two units are then fitted within the
outer housing of the transceiver. The housing is then
encased with a metal EMI protective shield.
The electrical subassembly carries the signal pins that exit
from the bottom of the transceiver. The solder posts are
designed to provide the mechanical strength required to
withstand the loads imposed on the transceiver by mating
with the LC connectored fiber cables. Although they are
not connected electrically to the transceiver, it is recom-
mended to connect them to chassis ground.
R
X
SUPPLY
NOTE
DATA OUT
QUANTIZER IC
DATA OUT
SIGNAL
DETECT
T
X
GROUND
DATA IN
DATA IN
Tx DISABLE
LASER BIAS
MONITORING
LASER DRIVER
AND CONTROL
CIRCUIT
LASER DIODE
MODULATOR
R
X
GROUND
PIN PHOTODIODE
PREAMPLIFIER
SUBASSEMBLY
LC
RECEPTACLE
LASER
OPTICAL
SUBASSEMBLY
T
X
SUPPLY
CASE
NOTE: NOSE CLIP PROVIDES CONNECTION TO CHASSIS GROUND FOR BOTH EMI AND THERMAL DISSIPATION.
Figure 3. Block Diagram
4
TOP VIEW
FRONT VIEW
SIDE VIEW
BACK VIEW
G MODULE - NO EMI SHIELD
SIDE VIEW
BOTTOM VIEW
DIMENSIONS IN MILLIMETERS (INCHES)
DIMENSIONS SHOWN ARE NOMINAL. ALL DIMENSIONS MEET THE MAXIMUM PACKAGE OUTLINE DRAWING IN THE SFF MSA.
Figure 4. AFCT-5962TLZ/TGZ/NLZ/NGZ/ATLZ/ATGZ Package Outline Drawing
5
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