AFCT-5961TLZ/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-5961TLZ/TGZ/ATLZ/ATGZ/NLZ/NGZ are high
performance, 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-5961TLZ/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
photodetector for low dark current and excellent re-
sponsivity.
A pseudo-ECL compatible logic interface simplifies
interface to external circuitry.
These transceivers are supplied in the new industry
standard 2 x 5 DIP style package with the LC fiber
connector interface and is footprint compatible with
SFF Multi Source Agreement (MSA).
Features
•
RoHS compliant
•
AFCT-5961TLZ/ATLZ
•
AFCT-5961NLZ
Links of 15 km with 9/125 µm single mode fiber
(S1.1)
Links of 40 km with 9/125 µm single mode fiber
(L1.1)
•
Multisourced 2 x 5 package style with LC receptacle
•
Single +3.3 V power supply
•
Temperature range:
AFCT-5961TLZ: 0 °C to +70 °C
AFCT-5961ATLZ: -40 °C to +85 °C,
AFCT-5961NLZ: -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-5961TLZ/TGZ/ATLZ/
ATGZ/NLZ/NGZ contains an InGaAs/InP photo detector
and a preamplifier mounted in an optical subassem-
bly. 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 il-
lustrated 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.
Noise Immunity
The receiver includes internal circuit components to
filter power supply noise. However under some condi-
tions 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
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-5961TLZ/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 condi-
tions. The optical output is controlled by a custom IC
that detects the laser output via the monitor photodi-
ode. 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.
FP
LASER
PHOTODIODE
(rear facet monitor)
DATA
DATA
LVPECL
INPUT
LASER
MODULATOR
LASER BIAS
DRIVER
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 subassem-
blies, a electrical subassembly and the housing as illus-
trated 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 5 DIP. The low profile of the Avago Technologies
transceiver design complies with the maximum height
allowed for the LC connector over the entire length of
the package.
The electrical subassembly consists of high volume
multilayer 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 subassemby 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 trans-
ceiver by mating with the LC connectored fiber cables.
Although they are not connected electrically to the
transceiver, it is recommended 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-5961TLZ/TGZ/NLZ/NGZ/ATLZ/ATGZ Package Outline Drawing
5
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