19-3848; Rev 1; 10/08
KIT
ATION
EVALU
BLE
AVAILA
155Mbps to 2.5Gbps Burst-Mode Laser Driver
General Description
The MAX3643 burst-mode laser driver provides bias
and modulation current drive for PON burst-mode ONT
applications. It is specifically designed for use with a
low-cost external controller for the APC (and if desired,
AMC) loop. A high-speed differential burst-enable input
enables the driver to switch the laser from a dark (out-
put off) condition to full on-condition in less than 2ns.
When BEN is inactive, typical modulation and bias cur-
rents are 5µA each.
Laser modulation current can be set from 10mA to 85mA
and bias current can be set from 1mA to 70mA using the
MODSET and BIASSET inputs. A sample-and-hold circuit
is provided to capture the monitor diode output during
short PON bursts, if needed, and the BEN high-speed
signal is mirrored on an LVCMOS output to be used by
the controller operating the APC/AMC loop.
The MAX3643 burst-mode laser driver is packaged in a
4mm x 4mm, 24-pin thin QFN package. It operates from
-40°C to +85°C.
♦
10mA to 85mA Modulation Current
♦
1mA to 70mA Bias Current
♦
Monitor Diode Sample and Hold
♦
45ps Output Transition Time
♦
2ns Turn-On/-Off Time
♦
Reference Voltage Generator
♦
LVPECL High-Speed Inputs (Data, Burst Enable)
Features
MAX3643
Ordering Information
PART
MAX3643ETG
MAX3643ETG+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 TQFN-EP*
24 TQFN-EP*
+Denotes
a lead-free/RoHS-compliant package.
*EP
= Exposed paddle.
Applications
A/B/GPON ONT Modules up to 2.5Gbps
1.25Gbps IEEE EPON ONT Modules
Pin Configuration appears at end of data sheet.
Typical Application Circuit
+3.3V
0.1μF
27nH
15Ω
+3.3V
FILTER
V
CC
24Ω
OUT-
10Ω
OUT+
10Ω
BIAS+
R
COMP
C
COMP
IN+
IN-
MAX3643
BEN+
BEN-
EN
IMAX
BCMON
VREF
VMSET
MODSET
VBSET
BIAS-
MDIN
MDOUT
BIASSET BENOUT GND
15Ω
V
CC
1kΩ
3kΩ
1kΩ
1kΩ
1kΩ
ANALOG OUT
ANALOG OUT
ANALOG IN
CONTROL
START CONVERT
ANALOG IN
ANALOG IN
CONTINUOUS
OPERATION
CONTROLLER
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
155Mbps to 2.5Gbps Burst-Mode Laser Driver
MAX3643
ABSOLUTE MAXIMUM RATINGS
Supply Voltage V
CC
..............................................-0.5V to +4.0V
Current into BIAS-, BIAS+, OUT-, OUT+ .......-20mA to +150mA
Voltage at VMSET, VBSET, IN+, IN-, BEN+, BEN-,
EN,
MDIN,
MDOUT, BENOUT, BIASMON ................-0.5V to (V
CC
+ 0.5V)
Voltage at MODSET, BIASSET, VREF, IMAX ........-0.5V to +3.0V
Voltage at OUT-, OUT+, BIAS-, BIAS+ .....+0.3V to (V
CC
+ 0.5V)
Continuous Power Dissipation (T
A
= +85°C)
24-Pin TQFN, Multilayer Board
(derate 27.8mW/°C above +85°C) ............................1807mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range ............................-55°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
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.
OPERATING CONDITIONS
PARAMETER
Supply Turn-On Time
Ambient Temperature
Data Rate
Voltage at VMSET, VBSET
Voltage at BIASMON
Voltage at MDIN
0
0
0
SYMBOL
10% to 90%
CONDITIONS
MIN
0.001
-40
TYP
MAX
1000
+85
2500
1.4
1.4
2.56
UNITS
ms
°C
Mbps
V
V
V
ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, I
BIAS
= 20mA, I
MOD
= 30mA, unless
otherwise noted.) (Note 1)
PARAMETER
Supply Current
I/O SPECIFICATIONS
LVPECL Differential Input Voltage
LVPECL Common-Mode Input
Voltage
LVCMOS Output High Voltage
LVCMOS Output Low Voltage
BENOUT Propagation Delay
LVCMOS Input Pullup Resistance
LVCMOS Input Current
LVCMOS Input High Voltage
LVCMOS Input Low Voltage
BIAS GENERATOR SPECIFICATIONS
Bias Current Range
Bias Current, Burst Off
BIASSET Current Gain
I
BIAS
I
BIAS, OFF
G
BIAS
V
BIAS+
, V
BIAS-
≥
0.6V
BEN = low or
EN
= high
1mA
≤
I
BIAS
<
2mA, VBSET = VREF
2mA
≤
I
BIAS
<
10mA, VBSET = VREF
10mA
≤
I
BIAS
<
70mA, VBSET = VREF
70
82.5
1
5
88
88
88
110
94.5
mA/mA
70
50
mA
µA
V
IN
= 0V or V
IN
= V
CC
2.0
0.2
T
d
V
IN
V
CM
I
OH
= -100µA
I
OL
= 100µA
C
L
= 20pF, from BEN zero crossing to 67%
CMOS level
75
50
V
CC
0.8
30
V
IN
= (V
IN+
) - (V
IN-
)
200
V
CC
-
1.49
V
CC
-
0.2
0.2
V
CC
-
1.32
1600
V
CC
-
V
IN
/ 4
mV
P-P
V
V
V
ns
kΩ
µA
V
V
SYMBOL
I
CC
CONDITIONS
Excluding laser bias and mode currents,
max at I
MOD
= 85mA, I
BIAS
= 70mA
MIN
TYP
32
MAX
51
UNITS
mA
2
_______________________________________________________________________________________
155Mbps to 2.5Gbps Burst-Mode Laser Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, I
BIAS
= 20mA, I
MOD
= 30mA, unless
otherwise noted.) (Note 1)
PARAMETER
BIASSET Current Gain Stability
BIASSET Current Gain Linearity
Bias Current Overshoot
Bias Current Monitor Gain
Bias Current Monitor Gain
Stability
BIASSET Resistor
MODULATOR SPECIFICATIONS
Modulation Current Range
Modulation Current Off
Instantaneous Voltage at OUT+
MODSET Current Gain
MODSET Current Gain Stability
MODSET Current Gain Linearity
MODSET, BIASSET Gain
Matching (Note 15)
Modulation Current Rise Time
Modulation Current Fall Time
Deterministic Jitter
Random Jitter
MODSET Resistor
MODSET, BIASSET Voltage
Range
Voltage Error
Input Leakage
TURN-OFF/-ON SPECIFICATIONS
Burst-Enable Time
Burst-Disable Time
(Notes 2, 6, 7)
(Notes 2, 6, 8)
2.3
2.0
ns
ns
(Note 5)
VMSET and VBSET pins
0.1
R
MOD
t
R
t
F
G
MOD
I
MOD
I
MOD, OFF
BEN = low or
EN
= high or V
IN
= low
10mA
≤
I
MOD
< 60mA
60mA
≤
I
MOD
≤
85mA
10mA < I
MOD
< 85mA, VMSET = VREF
(Note 13)
(Note 14)
I
BIASSET
= 0.15mA, I
MODSET
= 0.7mA
I
MODSET
= I
BIASSET
= 0.15mA
I
MODSET
= I
BIASSET
= 0.4mA
I
MODSET
= I
BIASSET
= 0.55mA
20% to 80%
20% to 80%
(Note 3)
(Note 4)
40
45
45
17
0.8
50
0.6
0.75
82.5
-4.4
-2.2
0.5
1.7
1
1
85
85
45
1.4
60
ps
ps
ps
P-P
ps
RMS
Ω
%
88
94.5
+4.4
+2.2
10
5
85
120
mA
µA
V
mA/mA
%
%
R
BIAS
G
BSM
SYMBOL
CONDITIONS
5mA
≤
I
BIAS
≤
70mA (Note 13)
5mA
≤
I
BIAS
≤
70mA (Note 14)
V
CC
turn-on/-off < 1s
2mA
≤
I
BIAS
≤
70mA, VBSET = VREF
1mA
≤
I
BIAS
< 5mA
5mA
≤
I
BIAS
≤
70mA
-5
40
50
11
14
±4
+5
60
Ω
MIN
-4.4
-3.75
TYP
MAX
+4.4
+3.75
10
17
UNITS
%
%
%
mA/A
%
MAX3643
MODSET, BIASSET OPERATIONAL AMPLIFIER SPECIFICATIONS
0.005
1.4
±5
1.5
V
mV
µA
_______________________________________________________________________________________
3
155Mbps to 2.5Gbps Burst-Mode Laser Driver
MAX3643
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, I
BIAS
= 20mA, I
MOD
= 30mA, unless
otherwise noted.) (Note 1)
PARAMETER
SAMPLE/HOLD SPECIFICATIONS
MDIN Voltage Range
MDOUT Settling
Sample/Hold Droop
Sampling Error
Relative to final value at 3µs, C
L
< 20pF
After 100µs (Note 9)
Final value measured after 10µs
(MDOUT - MDIN), burst width > 576ns
R
L
> 10kΩ, C
L
< 50pF
5mA < I
BIAS
, 10mA < I
MOD
(Note 10)
(Notes 2, 11)
3
R
IMAX
= 3kΩ
I
BIAS
+I
MOD
R
IMAX
= 5kΩ
R
IMAX
= 10kΩ
1.25Gbps (Note 12)
155
100
50
33
150
75
%
mA
1.175
3
0.05
2.56
±1
±2.56
±14
V
mV
mV
mV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
BANDGAP VOLTAGE REFERENCE SPECIFICATIONS
VREF Output
MODULATION/BIAS CURRENT DISABLE
Enable Time
Disable Time
R
IMAX
Range
Current Limit (Tested with I
BIAS
=
I
MOD
)
OPTICAL EVALUATION
Eye Margin
5.5
375
15
µs
ns
kΩ
1.235
1.295
V
Note 1:
DC parameters are production tested at T
A
= +25°C, guaranteed by design and characterization at T
A
= -40°C.
AC parameters are guaranteed by design and characterization.
Note 2:
For 10mA
≤
I
MOD
≤
85mA and 4mA
≤
I
BIAS
≤
70mA.
Note 3:
Deterministic jitter measured with a continuous pattern of 2
7
-1 PRBS, 80 ones, 2
7
-1 PRBS, 80 zeros at 1.25Gbps, and both
LVPECL inputs terminated by the network shown in Figure 3.
Note 4:
Random jitter, rise time, fall time measured with 0000011111 pattern at 1.25Gbps.
Note 5:
Voltage difference between VMSET and MODSET or VBSET and BIASSET excluding IR drops. The maximum operating
voltage at VMSET or VBSET must be less than 1.4V for proper operation.
Note 6:
Turn-on/-off time is when the BEN+/BEN- LVPECL inputs are used to control modulation and bias currents.
Note 7:
Burst-enable delay is measured between the time at which the rising edge of the differential burst-enable input reaches the
midpoint, and the time at which the combined output currents (bias plus modulation) reach 90% of their final level.
Note 8:
Burst-disable delay is measured between the time at which the falling edge of the differential burst-enable input reaches the
midpoint, and the time at which the combined output currents (bias plus modulation) fall below 10% of the bias-on current.
Note 9:
Droop measured with sample/hold output load of 10MΩ.
Note 10:
Enable delay is measured between the time at which the falling edge of the
EN
input reaches
≤
0.8V, and the time at which
the combined output currents (bias plus modulation) reach 90% of their final level.
Note 11:
Disable delay is measured between the time at which the rising edge of the
EN
input reaches
≥
2V, and the time at which
the combined output currents (bias plus modulation) fall below 10% of the bias-on current.
Note 12:
Excelight SXT5731-Q laser.
Note 13:
Current gain stability = [(Gain – nominal Gain) / nominal Gain], nominal Gain at V
CC
= 3.3V, T
A
= +25°C.
Note 14:
Gain linearity = (Gainmax – Gainmin), Gainavg = Gainmax - Gainmin
Gainavg/2
2
Note 15:
Gain matching =
Gain mod / Gainbias
−
Gain mod nom / Gainbiasnom
nominal at V
CC
= 3.3V, T
A
= +25°C.
Gain mod nom / Gainbiasnom
4
_______________________________________________________________________________________
155Mbps to 2.5Gbps Burst-Mode Laser Driver
Typical Operating Characteristics
(Typical values are at V
CC
= +3.3V, T
A
= +25°C, data pattern =
noted.)
OPTICAL EYE DIAGRAM
(1.25Gbps, 933MHz FILTER,
PATTERN 2
13
-1 + 80 CID)
MAX3643 toc01
MAX3643
2
7
-1
PRBS + 80 ones + 2
7
-1 PRBS + 80 zeros, unless otherwise
SUPPLY CURRENT vs. TEMPERATURE
(I
BIAS
= 20mA, I
MOD
= 30mA)
55
50
45
DJ (ps
P-P
)
I
CC
(mA)
40
35
30
25
20
15
10
EXCLUDES BIAS AND
MODULATION CURRENT
MAX3643 toc02
DETERMINISTIC JITTER
vs. MODULATION AMPLITUDE
27
24
21
18
15
12
9
6
3
0
MAX3643 toc03
60
30
EXCELIGHT SXT5731-Q LASER
AVERAGE OPTICAL POWER = 3dBm
EXTINCTION RATIO = 15dB
GbE MASK MARGIN = 33%
1.2
1.1
1.0
RANDOM JITTER (ps
RMS
)
0.9
-40
-20
0
20
40
60
80
10
20
30
TEMPERATURE (°C)
50 60
40
I
MOD
(mA)
70
80
RANDOM JITTER
vs. MODULATION AMPLITUDE
MAX3643 toc04
I
MOD
vs. I
MODSET
80
70
60
I
MOD
(mA)
50
40
30
20
10
0
MAX3643 toc05
90
0.8
0.7
0.6
0.5
0.4
0.3
0.2
10
20
30
40
50
60
70
80
I
MOD
(mA)
0
200
400
600
800
1000
I
MODSET
(μA)
I
BIAS
vs. I
BIASSET
MAX3643 toc06
I
MOD
vs. VMSET
(R
MODSET
= 1kΩ)
80
70
I
MOD
(mA
P-P
)
60
50
40
30
20
10
0
MAX3643 toc07
90
80
70
60
I
BIAS
(mA)
50
40
30
20
10
0
0
200
400
600
800
90
1000
0
0.2
0.4
0.6
VMSET (V)
0.8
1.0
1.2
I
BIASSET
(μA)
_______________________________________________________________________________________
5
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