Maxim MAX3668EHJ, MAX3668E-D Datasheet
General Description
The MAX3668 is a complete, +3.3V laser driver with
automatic power control (APC) circuitry for SDH/SONET
applications up to 622Mbps. It accepts differential
PECL inputs, provides bias and modulation currents,
and operates over a temperature range of -40°C to
+85°C.
An APC feedback loop is incorporated to maintain a
constant average optical power over temperature and
lifetime. The wide modulation current range of 5mA to
75mA and bias current of 1mA to 80mA are easy to
program, making this product ideal for use in various
SDH/SONET applications.
The MAX3668 also provides enable control and a failuremonitor output to indicate when the APC loop is unable
to maintain the average optical power. The MAX3668 is
available in a 5mm 32-pin TQFP package as well as in
dice.
Applications
622Mbps SDH/SONET Access Nodes
Laser Driver Transmitters
Section Regenerators
Features
♦ Single +3.3V or +5.0V Operation
♦ 38mA Supply Current at +3.3V
♦ Programmable Modulation Current from
5mA to 75mA
♦ Programmable Bias Current from 1mA to 80mA
♦ Rise/Fall Time <200ps
♦ Automatic Average Power Control with Failure
Monitor
♦ Complies with ANSI, ITU, and Bellcore
SONET/SDH Specifications
♦ Enable Control
MAX3668
†
+3.3V, 622Mbps SDH/SONET
Laser Driver with Automatic Power Control
________________________________________________________________ Maxim Integrated Products 1
Typical Operating Circuit
19-4799; Rev 2; 2/00
PART
MAX3668EHJ -40°C to +85°C
TEMP. RANGE PIN-PACKAGE
32 TQFP (5mm x 5mm)
Ordering Information
Pin Configuration appears at end of data sheet.
MAX3668E/D (see Note) Dice*
Note: Dice are designed to operate over a -40°C to +140°C
junction temperature (Tj) range, but are tested and guaranteed
at T
A
= +25°C.
*Contact factory for availability.
†
Covered by U.S. Patent numbers 5,802,089 and 5,883,910
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
+3.3V +3.3V
LASER
V
GND
CC
OUT-
OUT+
BIAS
MD
R-
6.3Ω
R+
20Ω
C
D
1.0µF
FERRITE
BEAD
R
D
5Ω
R
FILT
20Ω
C
FILT
5pF
C
MD
1000pF
130Ω
MAX3693
4:1
SERIALIZER
WITH
CLOCK GEN
PECL
82Ω
130Ω
DATA+
DATA-
82Ω
ENABLE
BIASMAX
MAX3668
MODSET
APCSET
FAIL
CAPC
0.1µF
MAX3668
+3.3V, 622Mbps SDH/SONET
Laser Driver with Automatic Power Control
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
DC ELECTRICAL CHARACTERISTICS
(VCC= +3.14V to +5.5V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC= +3.3V, TA= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Supply Voltage, VCC.............................................-0.5V to +7.0V
Current into BIAS ............................................-20mA to +150mA
Current into OUT+, OUT- ............................... -20mA to +100mA
Current into MD....................................................-5mA to +5mA
Voltage at DATA+, DATA-, ENABLE,
FAIL .......................................................-0.5V to (V
CC
+ 0.5V)
Voltage at OUT+, OUT-.............................+1.5V to (V
CC
+ 1.5V)
Voltage at MODSET, APCSET, BIASMAX,
CAPC............................................................... -0.5V to +3.0V
Voltage at BIAS .........................................+1.0V to (V
CC
+ 0.5V)
Continuous Power Dissipation (T
A
= +85°C)
32-Pin TQFP (derate 14.3mW/°C above +85°C)........ 929mW
Operating Junction Temperature Range...........-55°C to +150°C
Processing Temperature (Die).........................................+400°C
Storage Temperature Range ........................... -65°C to +165°C
Lead Temperature (soldering, 10s) ................................+300°C
ENABLE = low (Note 3)
V
BIAS
= V
CC
- 1.6V
(Note 2)
Sinking 100µA
Sourcing 50µA
(Note 4)
APC open loop
APC open loop
Figure 1
PECL compatible
CONDITIONS
V0.1 0.44V
OL
TTL Output Low Voltage
(FAIL)
V2.4 V
CC
- 0.3 V
CC
V
OH
TTL Output High Voltage
(FAIL)
V0.8V
IL
TTL Input Low Voltage
V2.0V
IH
TTL Input High Voltage
V0.8V
MD
Monitor Diode Input Voltage
(MD Pin)
µA100Bias Off Current
mA180I
BIAS
mA38 60Supply Current
Bias Current Range
µA18 1000I
MD
DC Monitor Diode Current
%-15 15
Monitor Diode Current
Absolute Accuracy
ppm/°C
-480 10 480
Monitor Diode Current Stability
µA-1 10I
IN
DATA+, DATA- Input Current
ppm/°C
390
Bias Current Stability
%-15 15Bias Current Absolute Accuracy
mVp-p200 1600V
ID
Differential Input Voltage
V
V
CC
-V
CC
-V
CC
-
1.49 1.32 V
ID
/4
V
ICM
Common-Mode Input Voltage
UNITSMIN TYP MAXSYMBOLPARAMETER
I
BIAS
= 80mA
I
BIAS
= 1mA 920
IMD= 1mA
IMD= 18µA (Note 5) 70
MAX3668
+3.3V, 622Mbps SDH/SONET
Laser Driver with Automatic Power Control
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS
(VCC= +3.14V to +5.5V, load as shown in Figure 2, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VCC= +3.3V,
T
A
= +25°C.) (Note 6)
Note 1: Characteristics at -40°C are guaranteed by design and characterization. Dice are tested at TA= +25°C only.
Note 2: Tested with R
MODSET
= 5.11kΩ (I
MOD
≈ 38mA), R
BIASMAX
= 4.56kΩ (I
BIAS
≈ 52mA), excluding I
BIAS
and I
MOD
.
Note 3: Both the bias and modulation currents will be disabled if any of the current set pins are shorted to ground.
Note 4: This assumes that the laser to monitor diode transfer function does not change with temperature.
Note 5: See Typical Operating Characteristics for worst-case distributions.
Note 6: AC characteristics are guaranteed by design and characterization.
Note 7: Total I
MOD
out of OUT+. Refer to the Design Procedure for information regarding current delivered to the laser.
Note 8: Input signal is a 622Mbps, 2
13
- 1 PRBS with 80 inserted zeros.
Note 9: Input signal is a 622Mbps, 11110000 pattern.
Note 10:PWD = (wider pulse – narrower pulse) / 2.
I
MOD
= 75mA
ENABLE = low (Note 3)
(Note 7)
Open loop
20% to 80%,
R
L
= 10Ω||20Ω load
CONDITIONS
ppm/°C
-620 175 620
Modulation Current Stability
µA200
mA575I
MOD
Modulation Current Range
Modulation Off Current
ns250Enable/Start-Up Delay
ps
70 155
Pulse-Width Distortion
(peak-to-peak)
%-15 15
Modulation Current Absolute
Accuracy
100 200
tR/t
F
Output Rise/Fall Time ps
230 375
UNITSMIN TYP MAXSYMBOLPARAMETER
(Notes 9, 10)
I
MOD
= 5mA
Figure 1. Required Input Signal and Output Polarity
I
MOD
= 5mA (Note 5) 300
Figure 2. Output Termination for Characterization
(Note 8) ps100Jitter Generation (peak-to-peak)
I
MOD
= 75mA
I
MOD
= 5mA
Bits80CID
Maximum Consecutive Identical
Digits at 622Mbps
I
MOD
= 75mA 10 135
DATA+
DATA-
(DATA+) -
(DATA-)
+
I
OUT
100mV MIN
800mV MAX
200mVp-p MIN
1600mVp-p MAX
I
MOD
V
CC
20Ω
1.0µF
OUT-
10Ω
OUT+
BIAS
20Ω
V
CC
1.0µF
12.4Ω
15Ω
MAX3668
OSCILLOSCOPE
50Ω
EYE DIAGRAM
(I
MOD
= 35mA)
MAX3668 TOC02
200ps/div
PATTERN = 213 - 1 + 80 CID
I
MOD
= 35mA
622Mbps
EYE DIAGRAM
(I
MOD
= 75mA)
MAX3668 TOC03
200ps/div
PATTERN = 213 - 1 + 80 CID
I
MOD
= 75mA
622Mbps
EYE DIAGRAM
(622Mbps, 1300nm LASER
WITH 467MHz FILTER)
MAX3668 TOC01
193ps/div
2
23
- 1 PRBS
10
0.01
1 10 100
MONITOR DIODE CURRENT
vs. APC SET RESISTOR
0.1
1
MAX3668 TOC04
R
APCSET
(kΩ)
I
MD
(mA)
1000
1
0.1 101 100
BIAS CURRENT vs.
MAXIMUM BIAS SET RESISTOR
10
100
MAX3668 TOC05
R
BIASMAX
(kΩ)
I
BIAS
(mA)
100
1
0.1 100 1000
MODULATION CURRENT
vs. MODULATION SET RESISTOR
10
MAX3688 TOC06
R
MODSET
(kΩ)
I
MOD
(mA)
101
16
17
19
18
20
21
04020 60 80
RANDOM JITTER
vs. MODULATON CURRENT
MAX3668 TOC07
I
MOD
(mA)
RANDOM JITTER (ps p-p)
INCLUDES RANDOM JITTER
DUE TO MEASUREMENT
EQUIPMENT
0
15
10
5
20
25
30
35
40
45
50
04020 60 80
PULSE-WIDTH DISTORTION
vs. MODULATION CURRENT
MAX3668 TOC08
I
MOD
(mA)
PWD (ps)
30
35
45
40
50
55
-40 10-15 35 60 85
SUPPLY CURRENT
vs. TEMPERATURE
MAX3668 TOC09
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
VCC = +3.3V
VCC = +5.0V
I
BIAS
= 48mA
I
MOD
= 33mA
MAX3668
+3.3V, 622Mbps SDH/SONET
Laser Driver with Automatic Power Control
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC= +3.3V, TA= +25°C, unless otherwise noted.)
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