Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Features
s
High data-rate clocked laser diode driver
s
Clock disable mode for data feedthrough
s
Adjustable high output current
s
Operation up to 3 Gbits/s
Applications
s
SONET/SDH transmission systems
s
SONET/SDH test equipment
s
Optical transmitters
Functional Description
The LG1627BXC is a gallium arsenide (GaAs) laser
diode driver to be used with direct modulated laser
diodes in high-speed non-return-to-zero (NRZ) trans-
mission systems. The device is made in a high-
performance 0.9 m gate GaAs hetero-junction FET
technology that utilizes high-density MIM capacitors,
airbridge interconnect, and NiCr film precision resis-
tors. The driver includes differential data and clock
inputs. The high-output, low overshoot drive current
and prebias can be set separately. Data retiming is
accomplished by the internal flip-flop, minimizing
jitter on the data. Clocking can be disabled for data
feedthrough. A pulse-width control enables the user
to compensate for laser turn-on delay. A 2.5 V band-
gap reference is required for stable operation over
temperature and varying power supply voltage.
Functional Diagram
5-6549(F).b
Figure 1. Functional Diagram
BG2P5
PWP
MOD_E
PWN
GND
I
OUT
MK
MK
V
SS1
CLK_E
CLK
CLK
V
IN
V
IN
V
TH
V
SS2
V
SS3
V
MOD
V
PRE
I
OUT-PRE
LG1627BXC
2
Agere Systems Inc.
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Block Diagram
5-7675(F)r.1
Figure 2. Block Diagram
V
PRE
V
MOD
MK
MK
GND
PWN
PWP
CLK_E
D
Q
V
TH
50
V
IN
V
IN
CLK
CLK
50
50
50
V
SS1
BG2P5
MOD_E
V
SS3
V
SS2
22
GND
I
OUT
I
OUT-PRE
Agere Systems Inc.
3
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Pin Information
5-6551(F).br.3
Figure 3. Pin Diagram
Table 1. Pin Descriptions
*
National Semiconductor
is a registered trademark of National Semiconductor Corporation.
Pin
Symbol
Description
1
V
TH
Capacitor to ground (data input reference).
2
V
IN
Data input.
3
Complementary data input.
4, 13, 14,
package
bottom
GND
Ground. For optimum performance, the package bottom must be soldered to the
ground plane.
5
CLK
Clock input.
6
CLK
Complementary clock input.
7
BG2P5
-
2.5 V band-gap reference (
National Semiconductor
* p/n LM4040).
8
MOD_E
Modulation enable (connect to V
SS1
to enable, float to disable).
9
PWP
Pulse width adjust positive.
10
PWN
Pulse width adjust negative.
11
MK
Complementary mark density output.
12
MK
Mark density output.
15, 16
I
OUT
Output modulation current (dc coupled to laser cathode).
17
I
OUT-PRE
Output prebias current.
18
V
PRE
Prebias control input.
19
V
SS2
V
SS2
supply
-
5.2 V for output prebias.
20
V
SS3
V
SS3
supply
-
5.2 V for output modulation.
21
V
MOD
Modulation current control input.
22, 23
V
SS1
V
SS1
supply
-
5.2 V.
24
CLK_E
Clock enable (connect to V
SS1
to enable, float to disable).
GND
GND
I
OUT
I
OUT
I
OUT-PRE
V
PRE
V
SS2
V
SS3
V
MO
D
V
SS1
V
SS1
CLK
_E
BG
2P
5
MOD_E
PW
P
PWN
MK
MK
V
TH
V
IN
GND
CLK
CLK
V
IN
1
2
3
4
5
6
7
8
9
10 11 12
13
14
15
16
17
18
19
20
21
22
23
24
V
IN
4
Agere Systems Inc.
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operational sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Recommended Operating Conditions
Table 3. Recommended Operating Conditions
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 a charged-device model (CDM) for ESD-susceptibility testing and protection design evaluation. ESD voltage
thresholds are dependent on the circuit parameters used to define the model. No industry-wide standard has been
adopted for the CDM. However, a standard HBM (resistance = 1500
, capacitance = 100 pF) is widely used and,
therefore, can be used for comparison. The HBM ESD threshold presented here was obtained by using these cir-
cuit parameters.
Table 4. ESD Threshold Voltage
Mounting and Connections
Certain precautions must be taken 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 nonswitching only), the soldering tip temperature should not be greater than
300 C and the soldering time for each lead must not exceed 5 seconds. This device is supplied with solder on the
back of the package. For optimum performance, it is recommended to solder the back of the package to ground.
Table 2. Absolute Maximum Ratings
Parameter
Symbol
Min
Max
Unit
Supply Voltage
V
SS
--
5.7
V
Input Voltage
V
I
GND
V
SS
V
Power Dissipation
P
D
--
1
W
Storage Temperature
T
stg
-
40
125
C
Operating Case Temperature Range
T
C
0
100
C
Parameter
Symbol
Min
Max
Unit
Case Temperature
t
CASE
0
70
C
Power Supply
V
SS
4.7
5.7
V
Human-Body Model ESD Threshold
Device
Voltage
LG1627BXC
>200
Agere Systems Inc.
5
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Electrical Characteristics
(T
A
= 25 C, V
SS1
= V
SS2
= V
SS3
= 5.2 V, data input = 600 mV (single ended),
and R
L
= 50
)
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.
Table 5. Electrical Characteristics
1. Excludes I
PRE
and average I
MOD
.
Power supply current I
SS2
(relating to prebias) is dependent on V
PRE
.
Power supply current I
SS3
(relating to modulation) is dependent on V
MOD
.
2. Maximum modulation at maximum V
MOD
.
3. Maximum prebias at maximum V
PRE
.
Parameter
Symbol
Min
Typ
Max
Unit
Data Input Voltage, Single Ended
V
IN
300
600
1000
mV
Power Supply Voltage
V
SS1
, V
SS2
, V
SS3
4.9
5.2
5.5
V
Power Supply Current
1
I
SS1
100
140
160
mA
Voltage Control for Output Modulation Current
V
MOD
4.0
--
5.5
V
Output Minimum Modulation Current
I
OUT LOW
--
0
2
mA
Output Maximum Modulation Current
2
I
OUT HIGH
75
85
--
mA
Voltage Control for Prebias Current
V
PRE
3.0
--
5.5
V
Output Minimum Prebias Current
I
PRE LOW
--
0
0.5
mA
Output Maximum Prebias Current
3
I
PRE HIGH
50
60
--
mA
Mark Density, 50% Duty Cycle (1 k
to GND)
MK
--
0.5
--
V
Mark Density Complement, 50% Duty Cycle
(1 k
to GND)
MK
--
0.5
--
V
Pulse Width Adjust Plus
PWP
3.0
4.2
5.5
V
Pulse Width Adjust Negative
PWN
3.0
4.2
5.5
V
Output Modulation I
OUT
= 40 mA, Clock Enabled
Output Rise and Fall Times (20%--80%)
t
R
, t
F
--
90
--
ps
Jitter (rms)
--
--
4
--
ps
Phase Margin
--
--
270
--
deg
Output Modulation I
OUT
= 40 mA, Clock Disabled
Output Rise and Fall Times (20%--80%)
t
R
, t
F
--
90
--
ps
Jitter (rms)
--
--
6
--
ps
Output Modulation I
OUT
= 80 mA, Clock Enabled
Output Rise and Fall Times (20%--80%)
t
R
, t
F
--
100
--
ps
Jitter (rms)
--
--
4
--
ps
Phase Margin
--
--
270
--
deg
Output Modulation I
OUT
= 80 mA, Clock Disabled
Output Rise and Fall Times (20%--80%)
t
R
, t
F
--
100
--
ps
Jitter (rms)
--
--
6
--
ps
6
Agere Systems Inc.
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Typical Optical Evaluations and Performance Characteristics
5-7693(F)r.4
Notes:
All bypass capacitors should be mounted close to the package.
For optimum performance, the package must be soldered to ground.
Mark density (MK and MK) outputs are terminated with 1 k
pull-up resistors.
For single-ended operation, unused data and clock inputs should be ac coupled to a 50
termination.
Pin 13 and pin 14 should be tied together with a separate path to the ground plane.
Figure 4. Typical Optical Evaluation of the LG1627BXC and D2500 Laser
Zo = 50
CLOCK
0.047
F
CLK
VO
LT
AG
E
DI
V
I
D
E
R
CURRE
NT
SE
NSE
V
SS
1
BY
PAS
S
1
2
3
4
5
6
7
8
9
10 11 12
13
14
15
16
17
18
19
20
21
22
23
24
LG1627BXC
CLOCKED LASER
DRIVER
Zo = 50
DATA
V
SS
1
V
SS3
V
MO
D
0.1
F
V
SS
= 5.2 V
0.047
F
1 k
1 k
MK
MK
CLK_E
V
IN
I
OUT
V
SS
2
I
OUT-PRE
V
PR
E
VOL
T
AGE
DI
VI
D
E
R
CURRE
NT
SE
NSE
Zo = 25
1
2
3
4
5
6
7
14
13
12
11
10
9
8
D2500
LASER
LASER
LASER
dc BIAS
0.1
F
3 k
0.1
F
2 k
V
SS
VOLTAGE
DIVIDER
0.1
F
1
V
SS
TO NODE
V
SS2
AND V
SS3
ONE EACH
TO USER
VOLTAGE MONITOR
(DVM)
CURRENT
SENSE
0.1
F
V
SS
TO
V
SS1
BYPASS
FOR V
SS1
REQUIRED TO SET
V
MOD
AND V
PRE
TO ACHIEVE DESIRED
MODULATION AND PREBIAS
V
TH
V
IN (OPTIONAL)
5 k
V
SS
= 5.2 V
MOD_E
BG2P5
LM4040
RF INPUT
2000
PW
P
PW
N
CLK
(OPTIONAL)
IN
IN
Agere Systems Inc.
7
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Typical Optical Evaluations and Performance Characteristics
(continued)
HORIZONTAL: 60 ps/div, VERTICAL: 1.5 mW/div
Figure 5. Typical Optical Eye-Diagram I
OUT
= 85 mA; I
OUT-PRE
= 5 mA
5-7676(F)
Figure 6. Typical I
OUT
vs. V
MOD
5-7677(F)r.1
Figure 7. Typical I
OUT-PRE
vs. V
PRE
0
10
20
30
40
50
60
70
80
90
100
I
OUT
(m
A)
5.5
4.5
5.0
4.0
V
MOD
(V)
0
10
20
30
40
50
60
70
80
I
OU
T
-
P
R
E
(m
A)
5.5
4.5
5.0
4.0
V
PRE
(V)
3.5
8
Agere Systems Inc.
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Outline Diagram
5-6555(F).a
Assembly Notes:
Standoff specifications apply to package prior to solder dipping of leads and package base.
During board assembly, use back lighting to silhouette the package. This will eliminate reflection problems with the solder on the
bottom of the package.
Lead space tolerance should be set to 0.012".
Board solder pattern for the package base should not exceed 50% of the package base area.
Insertion pressure should not exceed 125 grams.
Ordering Information
Device Code
Package
Temperature
Comcode
(Ordering Number)
LG1627BXC
24-pin hermetic small outline
0 C to 70 C
108325754
1
1
0 -- 0.004
0.082
0.005
0.092
0.045
0.035
0.030
0.012
0.280
0.465
Agere Systems Inc.
9
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Notes
Data Sheet
May 2001
LG1627BXC Clocked Laser Driver
Agere Systems Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or application.
Copyright 2001 Agere Systems Inc.
All Rights Reserved
Printed in U.S.A.
May 2001
DS01-219HSPL (Replaces DS99-143HSPL)
For additional information, contact your Agere Systems Account Manager or the following:
INTERNET: http://www.agere.com
E-MAIL: docmaster@micro.lucent.com
N. AMERICA:
Agere Systems Inc., 555 Union Boulevard, Room 30L-15P-BA, Allentown, PA 18109-3286
1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)
ASIA PACIFIC: Agere Systems Singapore Pte. Ltd., 77 Science Park Drive, #03-18 Cintech III, Singapore 118256
Tel. (65) 778 8833, FAX (65) 777 7495
CHINA: Agere Systems (Shanghai) Co., Ltd., 33/F Jin Mao Tower, 88 Century Boulevard Pudong, Shanghai 200121 PRC
Tel. (86) 21 50471212, FAX (86) 21 50472266
JAPAN: Agere Systems 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: DATALINE: Tel. (44) 7000 582 368, FAX (44) 1189 328 148
Technical 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 3507670 (Helsinki),
ITALY: (39) 02 6608131 (Milan), SPAIN: (34) 1 807 1441 (Madrid)
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