________________General Description
The MAX3263 is a complete, easy-to-program, single
+5V-powered, 155Mbps laser diode driver with com-
plementary enable inputs and automatic power control
(APC). The MAX3263 accepts differential PECL inputs
and provides complementary output currents. A tem-
perature-stabilized reference voltage is provided to
simplify laser current programming. This allows modu-
lation current to be programmed up to 30mA and bias
current to be programmed from up to 60mA with two
external resistors.
An APC circuit is provided to maintain constant laser
power in transmitters that use a monitor photodiode.
Only two external resistors are required to implement
the APC function.
The MAX3263's fully integrated feature set includes a
TTL-compatible laser failure indicator and a program-
mable slow-start circuit to prevent laser damage. The
slow-start is preset to 50ns and can be extended by
adding an external capacitor.
________________________Applications
Laser Diode Transmitters
155Mbps SDH/SONET
155Mbps ATM
____________________________Features
o
Rise Times Less than 1ns
o
Differential PECL Inputs
o
Single +5V Supply
o
Automatic Power Control
o
Temperature-Compensated Reference Voltage
o
Complementary Enable Inputs
_______________Ordering Information
MAX3263
Single +5V, Fully Integrated,
155Mbps Laser Diode Driver
________________________________________________________________
Maxim Integrated Products
1
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
SLWSTRT
IPIN
VCCA
GNDA
OUT+
GNDA
OUT-
GNDA
IBIASOUT
IMODSET
IBIASSET
IBIASFB
VREF2
IPINSET
FAILOUT
GNDB
VIN+
VIN-
GNDB
VCCB
ENB-
ENB+
VREF1
OSADJ
TOP VIEW
16
15
14
13
9
10
11
12
SSOP
MAX3263
___________________Pin Configuration
19-0432; Rev 1b; 4/98
PART
MAX3263CAG
0°C to +70°C
TEMP. RANGE
PIN-PACKAGE
24 SSOP
MAX3263
+5V
0.01
µ
F
0.01
µ
F
+5V
+5V
+5V
OUT+
IBIASOUT
IPIN
PECL
INPUTS
OUT-
FAILOUT
IBIASFB
OSADJ
IMODSET
IPINSET
IBIASSET
VCCA VCCB
VIN+
VIN-
ENB+
GNDB
GNDA
ENB-
SLWSTRT
VREF1
VREF2
LASER
2.7k
PHOTO-
DIODE
FERRITE BEAD
_____________Typical Operating Circuit
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX3263
Single +5V, Fully Integrated,
155Mbps Laser Diode Driver
2
_______________________________________________________________________________________
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.
T
A
= +25°C
(Note 1)
CONDITIONS
mA
12
I
REF
Available Reference Current
V
3.15
3.3
3.45
V
REF
mA
60
I
BIAS
Range of Programmable Laser
Bias Current
Reference Voltage
V
V
IL
TTL Low Input
mA
50
I
VCC
Supply Current
V
V
CC
- 1.165
V
IH
PECL Input High
V
V
CC
- 1.475
V
IL
PECL Input Low
V
2
0.8
V
IH
TTL High Input
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
Minimum differential input swing is 1100mVp-p
(Note 3)
CONDITIONS
mA
30
I
MOD
Range of Programmable
Modulation Current
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
I
BIAS
= 25mA, I
MOD
= 12mA, 4ns unit interval;
measured from 10% to 90%
ns
1
t
R
, t
F
Modulation-Current Rise and
Fall Time
I
MOD
= 12mA, T
A
= +25°C
%
±15
OS
Aberrations, Rising and Falling
Edge
I
BIAS
= 25mA, I
MOD
= 12mA, 8ns period
ps
100
PWD
Modulation-Current Pulse-
Width Distortion
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
Supply Voltages (V
CC
A, V
CC
B).............................-0.3V to +6V
VIN+, VIN-, FAILOUT ................................................0V to V
CC
OUT+, OUT-, IBIASOUT ......................................+1.5V to V
CC
ENB+, ENB- ......................V
CC
or +5.5V, whichever is smaller
Differential Input Voltage (
|
VIN+ - VIN-
|
).........................+3.8V
Input Current
IBIASOUT ............................................................0mA to 75mA
OUT+, OUT- ........................................................0mA to 40mA
IBIASSET ........................................................0mA to 1.875mA
IMODSET...............................................................0mA to 2mA
IPIN, IPINSET, OSADJ...........................................0mA to 2mA
FAILOUT..............................................................0mA to 10mA
IBIASFB................................................................-2mA to 2mA
Output Current
VREF1, VREF2.....................................................0mA to 20mA
SLWSTRT ..............................................................0mA to 5mA
Continuous Power Dissipation (T
A
= +70°C)
SSOP (derate 8mW/°C above +70°C) ..........................640mW
Operating Temperature Range...............................0°C to +70°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-55°C to +175°C
DC ELECTRICAL CHARACTERISTICS
(V
CC
= V
CC
A = V
CC
B = +4.75V to +5.25V, T
A
= 0°C to +70°C, unless otherwise noted. Typical values are at V
CC
= +5V and
T
A
= +25°C.)
AC ELECTRICAL CHARACTERISTICS
(V
CC
= V
CC
A = V
CC
B = +4.75V to +5.25V, R
LOAD
(at OUT+ and OUT-) = 25
connected to V
CC
, T
A
= 0°C to +70°C, unless other-
wise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.) (Note 2)
Loaded with 2.7k
pull-up resistor to V
CC
Loaded with 2.7k
pull-up resistor to V
CC
V
0.5
V
OL
FAILOUT Output Low
V
4.5
V
OH
FAILOUT Output High
Note 2:
AC characteristics are guaranteed by design and characterization.
Note 3:
An 1100mVp-p differential is equivalent to complementary 550mVp-p signals on VIN+ and VIN-.
Note 1:
I
VCC
= I
VCCA
+ I
VCCB
, I
BIAS
= 60mA, I
MOD
= 30mA, and I
PIN
= 140µA.
MAX3263
Single +5V, Fully Integrated,
155Mbps Laser Diode Driver
_______________________________________________________________________________________
3
0
0
20
40
R
BIASSET
vs. BIAS CURRENT
5
MAX3263-01
I
BIAS
(mA)
R
BIASSET
(k
)
60
3
1
4
2
6
7
8
0
0
5
10
15
20
25
R
MODSET
vs. MODULATION CURRENT
8
MAX3263-02
MODULATION CURRENT
(mAp-p)
R
MODSET
(k
)
30
6
4
2
10
12
DIFFERENTIAL INPUT
SWING = 1100 mVp-p
100
0
500
R
PINSET
vs. MONITOR CURRENT
MAX3263-03
MONITOR CURRENT (
µ
A)
R
PINSET
(
)
1000
10,000
1000
100,000
1,000,000
-10
-8
-6
-4
-2
0
2
4
6
8
10
0
20
40
PERCENT CHANGE IN MODULATION
CURRENT vs. TEMPERATURE
MAX3263-04
TEMPERATURE (°C)
% CHANGE (w.r.t. +25°C)
80
60
-2
-1
0
1
2
3
0
20
40
PERCENT CHANGE IN BIAS
CURRENT vs. TEMPERATURE
MAX3263-05
TEMPERATURE (°C)
% CHANGE (w.r.t. +25°C)
80
60
10
30
70
50
APC DISABLED
34
36
38
40
42
44
46
48
50
0
20
40
SUPPLY CURRENT
vs. TEMPERATURE
MAX3263-06
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
80
60
0
0
5
10
15
20
25
ALLOWABLE R
OSADJ
RANGE
vs. MODULATION CURRENT
8
MAX3263-07
MODULATION CURRENT
(mAp-p)
ALLOWABLE R
OSADJ
(k
)
30
6
4
2
10
12
ALLOWABLE
RANGE
0
0
400
800
1200
1600
MAXIMUM MODULATION CURRENT
vs. MINIMUM DIFFERENTIAL
INPUT SIGNAL AMPLITUDE
25
MAX3263-08
MINIMUM DIFFERENTIAL
INPUT SIGNAL AMPLITUDE
(mVp-p)
MAXIMUM MODULATION CURRENT
(mAp-p)
2000
20
15
10
5
30
35
40
R
MODSET
= 1.2k
R
OSADJ
= 2k
__________________________________________Typical Operating Characteristics
(MAX3263CAG loads at OUT+ and OUT- = 25
, V
CC
= V
CC
A = V
CC
B = +5V, T
A
= +25°C, unless otherwise noted.)
MAX3263
Single +5V, Fully Integrated,
155Mbps Laser Diode Driver
4
_______________________________________________________________________________________
______________________________________________________________Pin Description
NAME
FUNCTION
PIN
10
ENB+
Noninverting Enable TTL Input. Output currents are enabled only when ENB+ is high and
ENB- is low.
1
VREF2
Temperature-Compensated Reference Output. VREF2 is internally connected to VREF1.
12
OSADJ
Overshoot-Adjust Input. Connect to internal voltage reference through a resistor to adjust the
overshoot of the modulation output signal (see
Typical Operating Characteristics).
11
VREF1
Temperature-Compensated Reference Output. VREF1 is internally connected to VREF2.
13
IBIASFB
Bias-Feedback Current Output. Output from automatic power-control circuit. Connect to
I
BIASSET
when using APC.
14
IBIASSET
Laser Bias Current-Programming Input. Connect to internal voltage reference through a resis-
tor to set bias current (see
Typical Operating Characteristics).
I
BIASOUT
= 40 x (I
BIASSET
+ I
BIASFB
).
15
IMODSET
Laser Modulation Current-Programming Input. Connect to internal voltage reference through
a resistor to set modulation current (see
Typical Operating Characteristics).
I
MOD
= 20 x I
MODSET
.
16
IBIASOUT
Laser Bias Current Output. Connect to laser cathode through an R-L filter network (see the
Bias Network Compensation section).
17, 19, 21
GNDA
Ground for Bias and Modulation Current Drivers
22
VCCA
+5V Supply Voltage for Bias and Modulation Current Drivers. Connect VCCA to the same
potential as VCCB, but provide separate bypassing for VCCA and VCCB.
20
OUT+
Modulation Output. When VIN+ is low and VIN- is high, OUT+ sinks I
MOD
.
9
ENB-
Inverting Enable TTL Input. Output currents are enabled only when ENB+ is high and ENB- is low.
8
VCCB
+5V Supply Voltage for Voltage Reference and Automatic Power-Control Circuitry. Connect
VCCB to the same potential as VCCA, but provide separate bypassing for VCCA and VCCB.
6
VIN-
Inverting PECL Data Input
5
VIN+
Noninverting PECL Data Input
4, 7
GNDB
Ground for Voltage Reference and Automatic Power-Control Circuitry
3
FAILOUT
Failout Output. Active-low, open-collector TTL output indicates if automatic power-control
loop is out of regulation due to insufficient monitor-diode current (when VPIN is below the
2.6V threshold). Connect FAILOUT to VCC through a 2.7k
pull-up resistor.
2
IPINSET
Monitor Photodiode Programming Input. Connect INPINSET to VREF1 or VREF2 through a
resistor to set the monitor current when using automatic power control (see
Typical Operating
Characteristics).
18
OUT-
Modulation Output. When VIN+ is high and VIN- is low, OUT- sinks I
MOD
.
23
IPIN
Monitor Photodiode Current Input. Connect IPIN to photodiode's anode.
24
SLWSTRT
Slow-Start Capacitor Input. Connect capacitor to ground or leave unconnected to set start-up
time, t
STARTUP
= 25.4k
(C
SLWSTRT
+
2pF).
MAX3263
Single +5V, Fully Integrated,
155Mbps Laser Diode Driver
_______________________________________________________________________________________
5
_______________Detailed Description
The MAX3263 laser driver has three main sections: a
reference generator with temperature compensation, a
laser bias block with automatic power control, and a
modulation driver (Figure 1).
The reference generator provides temperature-com-
pensated biasing and a voltage-reference output. The
voltage reference is used to program the current levels
of the high-speed modulation driver, laser diode, and
PIN (p+, intrinsic, n-) monitor diode.
The laser bias block sets the bias current in the laser
diode and maintains it above the threshold current. A
current-controlled current source (current mirror) pro-
grams the bias, with IBIASSET as the input. The mirror's
gain is approximately 40 over the MAX3263's input
range. Keep the output voltage of the bias stage above
2.2V to prevent saturation.
The modulation driver consists of a high-speed input
buffer and a common-emitter differential output stage.
The modulation current mirror sets the laser modulation
current in the output stage. This current is switched
between the OUT+ and OUT- ports of the laser driver.
The modulation current mirror has a gain of approximately
20. Keep the voltages at OUT+ and OUT- above 2.2V to
prevent saturation.
MAX3263
VCCB
V
CC
20 x I
MODSET
40 x I
BIASSET
I
BIASOUT
IPIN
IPINSET
R
PINSET
1 x I
PINSET
IBIASSET
IBIASFB
R
BIASSET
IMODSET
R
MODSET
R
OSADJ
IOSADJ
VIN+
VIN-
ENB+
GNDA
ENB-
SLWSTRT
VREF1, VREF2
LASER
PHOTO-
DIODE
LOOP-
STABILITY
CAPACITOR
0.1
µ
F
GNDB
VCCA
OUT+
OUT-
FAILOUT
+2.6V
COMPARATOR
V
CC
x 3/5
TRANSCONDUCTANCE
AMPLIFIER
MAIN
BIAS
GENERATOR
BANDGAP
REFERENCE
BIAS
COMPEN-
SATION
Figure 1. Functional Diagram
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