Data Sheet
June 1999
LG1625AXF Laser Driver
Features
■High data-rate laser diode/LED driver
■Adjustable output current
■Operation up to 3 Gbits/s
■Single –5.2 V power supply
■90 ps rise and fall times
Applications
■SONET/SDH transmission systems
■SONET/SDH test equipment
■Optical transmitters
Description
The LG1625AXF is a gallium-arsenide (GaAs) laser
diode driver to be used with direct modulated laser
diodes in high-speed nonreturn-to-zero (NRZ) trans-
mission systems. The device is made in a high-per-
formance 0.9 µm gate GaAs heterojunction FET
technology that utilizes high-density MIM capacitors,
airbridge interconnect, and NiCr film precision resis-
tors.
The device contains three cascaded stages, oper-
ates with a single –5.2 V power supply and accepts
ECL level inputs. Voltages control the modulated out-
put current and laser prebias current. The
LG1625AXF is available in a 24-lead hermetic, gull-
wing package.
A test fixture (TF1006A) with SMA connectors is
availab le to allow quick ev aluation of the LG1625AXF.
5-7865(F)
Figure 1. Functional Diagram
VIN
MK
VSS1
VTH
VSS2
GND
IOUT
MK VPRE
VSS3
VMOD
LG1625AXF
2Lucent Technologies Inc.
Data Sheet
June 1999
LG1625AXF Laser Driver
Pin Information
5-7866(F)
Figure 2. LG1625AXF Die Block Diagram
5-7867(F)r.1
Note: Figure 3 is not to scale.
Figure 3. LG1625AXF Package Pinout
VIN
VTH
IOUT
VSS3
VMOD
VSS1
50 Ω
GND MKMK
VSS2
VPRE
25 Ω
+
–
+
–
+
–
VSS1
GND
GND
IOUT
GND
VPRE
VSS2
VSS3
VMOD
VSS1
VSS1
VTH
1
2
3
4
5
613
14
15
16
17
18
24
VTH
GND
GND
GND
MK
MK
VSS1
VIN
GND
GND
GND
VSS1
23
22
21
20
19
7
8
9
10
11
12
(OPTIONAL)
LG1625AXF
Lucent Technologies Inc. 3
Data Sheet
J une 1999 LG1625AXF Laser Driver
Pin Inform ation (continued)
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent or latent damage to the device. These
are absolute stress ratings only. Functional operation of the de vice is not implied at these or an y other conditions in
excess of those given in the operational sections of this device specification. Exposure to absolute maximum rat-
ings for extended periods can adversely affect device reliability.
Table 1. LG1625AXF Pin Description
Pin Symbol Type*
* I = input, O = output, P = power.
Name/Definition
1, 6, 13, 22, 23 VSS1 PVSS1 Supply. –5.2 V power supply pin.
2V
IN IData Input.
3, 4, 5, 8, 9, 10,
14, 15, 17 GND P Ground.
7, 24 VTH†
† Connection to VTH f or threshold adjustment should be made through pin 24. Pin 7 is made av ailab le f or additional by passing of VTH (See
Figure 5 on page 6, Typical Test Circuit).
IThreshold Control. Input (eye crossing).
11 MK OComplementary Mark Density Output.
12 MK O Mark Density Output.
16 IOUT OOutput. dc couple to laser cathode.
18 VPRE IPrebias Control Input.
19 VSS2 PVSS2. –5.2 V supply for output prebias.
20 VSS3 PVSS3. –5.2 V supply for output modulation.
21 VMOD IModulation Current Control Input.
Table 2. Absolute Maximum Ratings (at TA = 25 °C unless otherwise specified)
Parameter Symbol Min Max Unit
Supply Voltage VSS —–5.95V
Storage Temperature Tstg –40 125 °C
Operating Case Temperature Range TC075
°C
Input Voltage VIGND VSS V
Power Dissipation PD—1W
4Lucent Technologies Inc.
Data Sheet
June 1999
LG1625AXF Laser Driver
Handling Precautions
Although protection circuitry has been designed into this device, proper precautions should be taken to avoid expo-
sure to electrostatic discharge (ESD) during handling and mounting. Lucent employs a human-body model (HBM)
and charged-device model (CDM) for ESD-susceptibility testing and protection design evaluation. ESD voltage
thresholds are dependent on the circuit parameters used in the defined model. No industry-wide standard has
been adopted f or the CDM. Howe ver, a standard HBM (resistance = 1500 Ω, capa ci t a nc e = 10 0 pF) is w i de ly us ed
and, therefore, can be used for comparison purposes. The HBM ESD threshold presented here was obtained by
using these circuit parameters.
Mounting and Connections
Certain precautions must be tak en when using solder. For installation using a constant temperature solder , temper-
atures of under 300 °C may be employed for periods of time up to 5 seconds, maximum. For installation with a sol-
dering iron (battery operated or nons witching only), the soldering tip temper ature should not be greater than 300 °C
and the soldering time for each lead must not e xceed 5 seconds.
Table 3. ESD Threshold Voltage
Human-Body Model ESD Threshold
Device Voltage
LG1625AXF ≥200 V
Lucent Technologies Inc. 5
Data Sheet
J une 1999 LG1625AXF Laser Driver
Electrical Characteristics
TA = 25 °C, VSS1 = VSS2 = VSS3 = –5.2 V, VTH = –1.3 V, VMOD = –3.4 V, RL = 25 Ω, data input = 600 mVp-p.
Minimum and Maximum values are testing requirements. Typical values are characteristics of the device and are
the result of engineering evaluations. Typical values are for information purposes only and are not part of the test-
ing requirements. Stresses in excess of the absolute maximum ratings can cause permanent damage to the
device.
5-7869(F)
Figure 4. Typical Eye Diagram of IMOD
Table 4. Electrical Characteristics
Parameter Symbol Min Typ Max Unit
Data Input Voltage VINp-p 300 600 2000 mV
Voltage Control for Output Modulation
Current VMOD –5.5 — –3.0 V
Output Modulation Current
Minimum
Maximum*
* Maximum modulation at maximum VMOD
IMOD LOW
IMOD HIGH —
55 0
65 2
—mA
mA
Voltage Control for Prebias Current VPRE –5.5 — –3.0 V
Output Prebias Current
Minimum
Maximum†
† Maximum prebias at maximum VPRE
IPRE LOW
IPRE HIGH —
30 0
40 0.5
—mA
mA
Output Rise & Fall Times (20%—80%)
Rise
Fall TRISE
TFALL —
—90
90 —
—ps
ps
Power Supply Voltage VSS1, VSS2, VSS3 –4.9 –5.2 –5.5 V
Power Supply Current‡
‡ Excludes IPRE and average IMOD. Power supply current ISS2 (relating to prebias) is dependant on VPRE. Power supply current ISS3
(relating to modulation) is dependant on VMOD
ISS1 50 100 120 mA
HORZ.: 100 pS/DIV., VERT.: 15 mA/DIV.
6Lucent Technologies Inc.
Data Sheet
June 1999
LG1625AXF Laser Driver
Test Circuit
Notes:
GND pins 3, 4, 5, 8, 9, 10, 14, 15, 17.
VSS1 pins 1, 6, 13, 22, 23. 5-7876(F)r.1
Figure 5. LG1625AXF Typical Test Circuit
LG1625AXF App l ica tion Notes
■VSS bypass capacitors should be mounted close to the package.
■5000 Ω potentiometer is typically set f or 2500 Ω. This estab lishes an approximate –1.3 V VTH which will track
with VSS.
■Mark density (MK and MK) outputs are terminated with 1 kΩ pull-up resistors.
■IMOD and IPRE can be measured and used to control VMOD and VPRE.
VIN
MK
VTH
VTH VSS1
MK
IOUT
VPRE
VMOD
VSS2
VSS3
LG1625AXF
1000 Ω
0.1 µF1000 Ω
500 Ω
0.1 µF
1000 Ω
VSS –5.2 V
0.1 µF
0.1 µF
1 Ω
1 Ω
50 Ω50 Ω
5000 Ω
0.1 µF
50 Ω
500 Ω
0.1 µF
1000 Ω
VSS –5.2 V
IPRE IF VPRE > –5.0 V
IMOD
0.1 µF
0.1 µF
VSS –5.2 V
+
12 11
18
21
16
20
19
7
2
24
20 Ω
20 Ω
IMOD
MONITOR
IPRE
MONITOR
SCOPE
DATA
GENERATOR
x x
MK
MK
Lucent Technologies Inc. 7
Data Sheet
J une 1999 LG1625AXF Laser Driver
Typical Performance Characteristics
5-7870(F)r.1
Figure 6. Output Modulation Current IMOD vs. the External Control Voltage VMOD
or Output Prebias Current IPRE vs. the External Control Voltage VPRE
100
80
60
40
20
0
–5.0 –4.5 –4.0 –3.5 –3.0 –2.5
–––I
MOD
(mA) or ---I
PRE
(mA)
V
MOD
(V) OR V
PRE
(V)
0
°
C
25
°
C
50
°
C
75
°
C
V
SS
=
V
SS
=
V
SS
=
–5.9 5 V
–5.2 0 V
–4.4 5 V
V
SS
= –5.95 V
V
SS
= –5.20 V
V
SS
= –4.45 V
V
SS
= –5.95 V
V
SS
= –5.20 V
V
SS
= –4.45 V
8Lucent Technologies Inc.
Data Sheet
June 1999
LG1625AXF Laser Driver
Typical Performance Characteristics (continued)
5-7871(F)
Figure 7. Typical TRISE or TFALL vs. VSS for IMOD = 40 mA
5-7872(F)
Figure 8. Typical MK or MK vs. VSS for IMOD = 40 mA
100
80
60
40
–6.0 –5.5 –5.0 –4.5 –4.0
TRISE OR TFALL (ps)
VSS (V)
75 °C
50 °C
25 °C
0 °C
–600
–650
–700
–750
–6.0 –5.5 –5.0 –4.5
MK or MK (mV)
VSS (V)
–550
75 °C
50 °C
25 °C
0 °C
Lucent Technologies Inc. 9
Data Sheet
J une 1999 LG1625AXF Laser Driver
Outline Diagram
24-Pin, Gull-Wing, Surface-Mou nt Package
Dimensions are in inches. Tolerance is ±0.005 inches unless otherwise noted.
5-7875(F)r.2
Ordering Information
Device Type Comcode (Ordering Number)
LG1625AXF 24-Lead Gull Wing 107529067
TF1006A Test Fixture 106733371
LUCENT
1625AXF
XXXXXX
0.364 SQ.
0.260
0.050
0.012
0.008
BEFORE
SOLDER
DIP
0.604
±0.015 TYP.
R0.010
0.065
0.074
0.010
BEFORE
SOLDER
DIP
1
10 Lucent Technologies Inc.
Data Sheet
June 1999
LG1625AXF Laser Driver
Appendix
The test fixture mentioned in the data sheet is sold separately and is described in detail below.
5-7868(F)
Figure 9. TF1006A Test Fixture
TF1006A Test Fixture Features
■SMA connectors
■Easy package placement
■Good RF performance
Test Fixture Functional Description
The TF1006A test fixture is used to characterize 24-lead gullwing packages for high-speed fiber-optic communica-
tions. The fixture is a metallized substrate (PTFE filled material) f astened to a brass base. The package leads make
contact to the microstrip lines on the fixture through use of a pressure ring and two thumb screws.
Three RF connectors are provided for connections to the input and outputs. BNC connectors are provided on sol-
dered leads for dc bias lines.
The TF1006A is preassembled and fully tested prior to shipment.
Lucent Technologies Inc. 11
Data Sheet
J une 1999 LG1625AXF Laser Driver
Appendix (continued)
Test Fixture Function al Description (continued)
5-7873(F)
Figure 10. TF1006A Electrical Diagram
Before Use of Test Fixture
■Due to possib le stress during shipment, SMA connectors may be misaligned.
■Check each SMA for continuity.
■If necessary, realign and retighten with a 5/64 in. hex key wrench.
Instructions for Use of Test Fixture
A pair of flat-tip tweezers can be used to insert or remov e a package from the test fixture. Alwa ys wear a grounding
strap to prevent ESD.
1. To insert a package, remove the two thumb screws and gently lift the pressure ring off of the test fixture.
2. Place the pressure ring, cavity side up, on a flat ESD safe surface.
3. Connect the metal tube to a suitable vacuum source with flexible tubing.
4. Place the package, lid down, on a flat ESD saf e surface. Locate pin 1 on the package.
8
9
10
11
12
0.01 µF
0.01 µF
0.01 µF
0.01 µF
0.01 µF
0.01 µF
VSS1
VTH
VSS1
VMOD
VSS3
VSS2
VSS1 VIN
0.01 µF
MK
MK
0.01 µF
100 Ω
100 Ω
100 Ω
100 Ω
0.01 µF
1
24
21
20
19
13 14 15 16 18
65432
23
22
17
FIXTURE BOUNDARY
PACKAGE OUTLINE
VSS1 GND VPRE
IOUT
Data Sheet
June 1999
LG1625AXF Laser Driver
Lucent Technologies Inc. reserves the right to make changes to the product(s) or infor mation contained herein without notice. No liability is assumed as a result of their use or application. No
rights under any patent accompany the sale of any such product(s) or information.
Copyright © 1999 Lucent Technologies Inc.
All Rights Reserved
June 1999
DS99-187HSPL
For additional information, contact your Microelectronics Group Account Manager or the following:
INTERNET: http://www.lucent.com/micro
E-MAIL: docmaster@micro.lucent.com
N. AMERICA: Microelectronics Gro up, Lucent Technologies Inc., 555 Union Bo ul evard, Room 30L-1 5P-BA, Allentown, PA 181 03
1-800-372-2447, FAX 610-71 2-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)
ASIA PACI FIC: Microelectronics Group, Lucent Technologies Singapore Pte. Ltd., 77 Science Park Drive, #03-18 Cintech III, Singapore 118256
Tel. (65) 778 8833, FAX (65) 777 7495
CHIN A: Microelectronics Gr oup, Lu c ent Techno logies (Chi na) C o., Ltd., A - F 2, 23/F, Zao Fong Uni verse Bui lding, 1800 Zhong Shan Xi Road, Sha ngh ai
200233 P. R. China Tel. (86) 21 6440 0468, ext. 316, FAX (86) 21 6440 065 2
JAPAN: Microelectronics Group, Lucent Technologies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan
Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700
EUROPE: Data Requests: MICROELECTRONICS GROUP DATALINE: Tel. (44) 1189 324 299, FAX (44) 1189 328 148
Te chnical Inquiries: GERMANY: (49) 89 95086 0 (Munich), UNITED KINGDOM: (44) 1344 865 900 (Ascot),
FRANCE: (33) 1 40 83 68 00 (Paris), SWEDEN: (46) 8 594 607 00 (Stockholm), FINLAND: (358) 9 4354 2800 (Helsinki),
ITALY: (39) 02 6608131 (Milan), SPAIN: ( 34) 1 807 1441 (Madrid)
Appendix (continued)
Instructions for Use of Test Fixture (continued)
5. Insert the package into the pressure ring (lid down) with pin 1 located next to the orientation mark and turn on
the vacuum. The vacuum will retain the package in the pressure ring during the following steps.
6. Align the vertically conductive material on the circuit board.
7. Place the pressure ring down over the alignment pins and gently tighten the thumb screws.
8. Remove vacuum, if desired.
Note: Pressure ring not shown. 5-7874(F)
Figure 11. TF1006A Connector Assignment
DATA IN
(OPTIONAL) VSS1
NC
GND
MK
MK
GND
(OPTIONAL) VSS1
VSS1 (OPTIONAL)
GND
VTH
VSS1
VMOD
VSS3
VSS2
GND OUTPUT
VPRE
LW5
