OC-48/STM-16 Transmitter
STX48 Series
Product Description
The STX48 modules are laser transmitters designed to meet or exceed
the SONET/SDH optical interface requirements at OC-48/STM-16 (2.5
Gb/s) data rate. Many performance versions are available which are fully
compliant with Short Reach, Intermediate Reach and Long Reach specifi-
cations at 1310 nm or 1550 nm wavelength. The Short Reach version uses
uncooled Fabry Perot lasers while the Intermediate Reach version uses
uncooled DFB lasers. For the Long Reach version, uncooled DFB lasers
with internal optical isolators are used. All modules satisfy Class I Laser
Safety requirements in accordance with the US FDA/CDRH and interna-
tional IEC-825 standards.
The transmitter incorporates an Automatic Power Control (APC) circuit to
maintain the optical output power at a constant level against variations
in ambient temperature and device aging. It also features a Mode Selec-
tor input pin which selects between clocked and non-clocked operation.
In the clocked operation mode, the input DATA is resynchronized by the
input CLOCK before driving the laser diode in order to reduce output jit-
ter to a minimum. A Transmitter Disable control input is also provided.
Both the laser bias current and back-facet light output can be monitored
as well.
All STX48 transmitter modules are available in two power supply options:
single +5V and single -5 V. The DATA and CLOCK interface can either be
direct PECL/ECL or via AC coupling. The operating temperature range is
-40°C to +85°C for the Short Reach and Intermediate Reach 1310 nm ver-
sion and 0°C to +70°C for the Long Reach version. All modules are housed
in a 24-pin dual-in-line metal package with a single mode fiber pigtail,
which is terminated with ST, FC or SC connector.
Features
Fully compliant with SONET/SDH OC-48/ STM-16
(2.5 Gb/s) specifications
Long Reach 1310 nm & 1550 nm as well as
Intermediate Reach and Short Reach
Eye Safe (Class I Laser Safety)
Mode Selector switch between Clocked or Non-
clocked operation
-40°C to +85°C Operating Temperature
(Intermediate Reach and Short Reach)
24-pin DIP metal package
FC, ST, SC-connectorized fiber pigtails
Differential PECL DATA & CLOCK interface
Single +5 V and - 5 V supply option
Absolute Maximum Ratings
Parameter
Storage Temperature
Operating Case Temperature
1
Supply Voltage
Input Voltage
Lead Soldering Temperature & Time
“I” option (SR & IR only)
“H” option
Symbol
T
ST
V
OP
V
CC
- V
EE
V
IN
- V
EE
-
Minimum
- 40
- 40
0
0
V
EE
-
Maximum
+ 85
+ 85
+ 70
+ 6.0
V
CC
- V
EE
260°C, 10 sec
Units
°C
°C
V
V
R04.2008.04.30
Oplink Communications, Inc.
STX48 Series
Transmitter Performance Characteristics
Parameter
Data Rate
Average Optical Output Power (50% duty cycle)
Extinction Ratio
Short Reach (SR)
Intermediate Reach (IR)
Long Reach (LR) 1310 nm
Long Reach (LR) 1550 nm
Short Reach
Intermediate Reach & Long Reach
Intermediate Reach & Long Reach
(Over Operating Case Temperature.)
Symbol
B
P
O
P
hi
/P
lo
Minimum
0.05
- 10.0
- 5.0
- 2.0
8.2
1266
λ
C
1266
1280
1500
Δλ
RMS
Δλ
20
SMSR
-
-
30
Typical
2.5
- 7.0
- 3.0
0
-
1310
1310
1310
1550
-
-
-
Maximum
3.0
- 3.0
0
3.0
-
1360
1360
1335
1580
4.0
1.0
-
dB
nm
nm
dB
dBm
Units
Gb/s
Center Wavelength
Spectral Width (RMS)
Spectral Width (-20 dB)
Side Mode Suppression
Ratio
Transmitter Output Eye
Compliant with Bellcore TR-NWT-000253 and ITU-T Recommendation G.957
Receiver Electrical Interface
Parameter
Supply Voltage
1
Supply Current
Input HIGH Voltage (DATA & CLOCK, PECL)
Input LOW Voltage (DATA & CLOCK, PECL)
Input Voltage (DATA & CLOCK, PECL)
Input DATA & CLOCK timing
MODE SELECTOR
Input Voltage
Clocked
Non-Clocked
Symbol
V
CC
- V
EE
I
V
IH
V
IL
V
IN
T
DC
V
MSCK
V
MSNCK
V
DIS
V
EN
V
ALMH
V
ALML
V
BM, DIF
V
FM,DIF
Minimum
4.75
-
V
CC
- 1.165
V
CC
- 1.810
0.30
200
V
EE
V
CC
- 1.5
V
CC
- 2.0
V
EE
V
CC
V
EE
- 1.0
-
-
10
Typical
5.0
200
-
-
0.80
-
-
-
-
-
-
-
100
300
100
Maximum
5.25
300
V
CC
- 0.880
V
CC
- 1.475
1.00
300
V
EE
+ 1.5
V
CC
V
CC
V
EE
+ 0.6
V
EE
V
CC
V
EE
+ 0.5
200
500
250
Units
V
mA
V
V
Vp-p
ps
V
V
V
V
V
V
mV
mV
Transmitter Disable Voltage
Transmitter Enable Voltage
LD Bias Alarm
Output Voltage
Differential Bias
Monitor Voltage
1
HIGH Voltage
LOS Voltage
at 25
Decreasing Light Input
Differential Back Facet Monitor Voltage
For +5V single supply modules, connect VCC to +5V and VEE to 0V or GND (circuit ground). The package housing is internally connected to VEE.
For - 5V single supply modules, connect VCC to 0V or GND (circuit ground) and VEE to - 5V. The package housing is internally connected to VCC.
Related OC-48/STM-16 Transceiver & Receiver Modules
SRX-48
SRC-48
DTR-2488-SM
DTR-2488-SM2
DTC-48
: Receiver without Clock Recovery (24-pin DIP)
: Receiver with Clock Recovery (24-pin DIP)
: Transceiver without Clock Recovery (industry standard 1x9 package)
: Transceiver without Clock Recovery (industry standard 2x9 package)
: Transceiver with Clock Recovery (industry standard 2x9 package)
Oplink Communications, Inc.
2
R04.2008.04.30
STX48 Series
Application Notes
When the DATA+ input is at logic HIGH and DATA- input is
at logic LOW, the LD is ON; and vice versa. The transmitter is
normally enabled (i.e. when the TX DISABLE control input is
not connected). When the TX DISABLE input voltage is higher
than
V
CC
- 2 V, the laser is disabled (less than -30dBm output
power) independent of the input data.
The transmitter incorporates an Average Power Control (APC)
loop to stabilize the transmitter average optical output power
against temperature variation. The APC loop always acts
to keep the transmitter average optical output power at a
constant value (when the transmitter is enabled). Therefore,
when the input data is all continuous “zeroes” or all continuous
“ones”, the transmitter optical output power is a constant level
equal to the nominal average optical output power (not at the
“OFF” level or at the “ON” level).
When the MODE SELECTOR input is left unconnected or at
logic “LOW” (V
EE
to
V
EE
+ 1.5V), the transmitter is in clocked
Interface Circuit
operation mode. In this mode, the input clock resynchronizes
the incoming data to reduce timing jitter. The timing between
the DATA and CLOCK inputs is as shown below. When the
MODE SELECTOR input at logic “HIGH” (V
CC
- 1.5V to
V
CC
),
the transmitter is in non-clocked operation mode. In this
mode, the CLOCK inputs are not used and hence need not
be provided.
The transmitter has internal 50 ohm termination to
V
TD
(pin 6)
for DATA inputs &
V
TC
(pin 19) for CLOCK inputs. The DATA &
CLOCK interface can be either direct PECL/ECL coupling or via
AC coupling as shown below. The use of differential signals is
strongly recommended. In cases where only single-ended signal
is available, the unused DATA input pin should be biased to
V
CC
- 1.29 V for direct PECL/ ECL coupling or bypassed to AC Ground
for AC coupling. Similarly, the unused CLOCK input pin should
be bypassed with a 0.01 μF capacitor to
V
EE
.
50 ohm line
DATA+ / CLK+
VCC
- 2 V
7 / 18
6 / 19
DATA+/
CLK+
50 ohm line
0.022
0.01
7 / 18
6 / 19
0.01
STX-48
5 / 20
DATA-/
CLK-
50 ohm line
DATA- / CLK-
50 ohm line
0.022
STX-48
5 / 20
DIFFERENTIAL
DIRECT-COUPLED PECL
DIFFERENTIAL
AC-COUPLED
Monitor Circuit
VCC
LD
I
b
10Ω
BM
+
-
I
mon
200Ω
VCC
PD
3KΩ
FM
+
Timing Diagram (Clocked Operation)
T
DC
DATA
3KΩ
3KΩ
Bias
Circuit
VEE
BM
3KΩ
FM
-
Control
Circuit
VEE
CLOCK
Oplink Communications, Inc.
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R04.2008.04.30
STX48 Series
Package Outline
(Dimension in inches)
46335 Landing Parkway Fremont, CA 94538-6407 Tel: (510) 933-7200 Fax: (510) 933-7300 Email: Sales@Oplink.com
Pinout Assignments
PIN
1
2
3
4
5
6
7
8
9
10
11
12
VCC
VCC
FM + (LD FACET MONITOR +)
FM - (LD FACET MONITOR -)
DATA INPUT -
VTD (TERMINATION FOR DATA)
DATA INPUT +
DO NOT CONNECT
(FOR INTERNAL USE ONLY)
VCC
VCC
VEE
VEE
FUNCTION
PIN
24
23
22
21
20
19
18
17
16
15
14
13
VCC
VCC
BM+ (LD BIAS MONITOR +)
BM- (LD BIAS MONITOR -)
CLK - (INPUT CLOCK -)
VTC (TERMINATION FOR CLK)
CLK+ (INPUT CLOCK +)
MODE SELECTOR
(CLOCKED or NON-CLOCKED)
TX DISABLE INPUT
ALM (LD BIAS ALARM)
VEE
VEE
FUNCTION
Laser Safety:
All transceivers are Class I Laser
products per FDA/CDRH and IEC-60825 stan-
dards. They must be operated under specified
operating conditions.
Oplink Communications, Inc.
DATE OF MANUFACTURE:
This product complies with
21 CFR 1040.10 and 1040.11
Meets Class I Laser Safety Requirements
Ordering Information
STX
4
8
0
0
0
Type
2x5 +5V= 4
2x5 -5V= B
Optical Output Power
-7dBm (Typ.)= B
-3dBm (Typ.)= D
0dBm (Typ.)= F
Temperature Range
-40 ~85˚C (SR & IR only)= I
0~70˚C (LR only)= H
Option
pigtail FC= P1
pigtail ST= P2
pigtail SC= P3
Distance Option
Short Reach (-7dBm only)= S0
Intermediate Reach (“-3dBm” only)=S3
Long Reach1310nm (“0dBm” only)= S4
Long Reach1550nm (“0dBm” only)= F2
Oplink Communications, Inc. reserves the right to make changes in equipment design or specifications without notice. Information supplied by Oplink Commu-
nications, Inc. is believed to be accurate and reliable. However, no responsibility is assumed by Oplink Communications, Inc. for its use nor for any infringements
of third parties, which may result from its use. No license is granted by implication or otherwise under any patent right of Oplink Communications, Inc.
R04. 2008.04.30
© 2008, Oplink Communications, Inc.
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