19-4803; Rev 1; 12/02
10.7Gbps EAM Driver
General Description
The MAX3935 is designed to drive an electro-absorp-
tion modulator (EAM) at data rates up to 10.7Gbps. It
provides programmable output levels through external-
ly adjustable bias and modulation currents. This EAM
driver is fabricated with Maxim’s in-house second-gen-
eration SiGe process.
The MAX3935 accepts differential ECL or ground-refer-
enced CML clock and data-input signals. Inputs are
terminated with on-chip 50Ω resistors. An input-data
retiming latch can be used to reject input-pattern-
dependent jitter if a clock signal is available.
The driver can modulate EAM devices at amplitudes up
to 3.0V
P-P
when the device impedance is 50Ω. Typical
(20% to 80%) edge speeds are 34ps. The output has
an on-chip 75Ω resistor for back termination. The
MAX3935 allows for an EAM bias voltage up to 1.2V.
The MAX3935 also includes an adjustable pulse-width
control circuit to precompensate for asymmetrical EAM
characteristics.
o
Single -5.2V Power Supply
o
Low 110mA Supply Current
o
34ps Typical Rise/Fall Time
o
o
o
o
o
o
Up to 10.7Gbps (NRZ) Operation
On-Chip Termination Resistors
Programmable Modulation Voltage Up to 3.0V
P-P
Programmable EAM Bias Voltage Up to 1.2V
Adjustable Pulse-Width Control
Selectable Data Retiming Latch
Features
MAX3935
†
o
Modulation Enable Control
o
ESD Protection
Ordering Information
PART
MAX3935EGJ
MAX3935E/D
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
32 QFN-EP*
Dice**
Applications
SONET OC-192 and SDH STM-64
Transmission Systems
DWDM
Metro and Long-Haul Transmitters
Add/Drop Multiplexers
*EP
= exposed pad.
**Dice
are designed to operate over this range, but are tested and
guaranteed at T
A
= +25°C only. Contact factory for availability.
For the latest package outline information, go to
www.maxim-ic.com/packages.
Pin Configuration appears at end of data sheet
Typical Application Circuit
V
BIASREF
-5.2V
-5.2V
BIASMON
DATA+
50Ω
DATA+
MODN1
DATA-
50Ω
DATA-
MOD
50Ω
V
OUT
BIASSET
GND
EAM
50Ω
MAX3952
10Gbps SERIALIZER
CLK+
CLK-
50Ω
50Ω
MAX3935
V
TT
CLK+
MODN2
BIAS
CLK-
PWC+
PWC- MODEN RTEN MODMON MODSET V
EE
-5.2V
-5.2V
-5.2V
L
100pF
R
PWC
2kΩ
100Ω -5.2V
V
MODREF
-5.2V
-5.2V
REPRESENTS A CONTROLLED–IMPEDANCE TRANSMISSION LINE
†
Covered by U.S. patent number 5,883,910.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
10.7Gbps EAM Driver
MAX3935
†
ABSOLUTE MAXIMUM RATINGS
Supply Voltage V
EE
...............................................-6.0V to +0.5V
V
TT
...........................................................(V
EE
- 0.5V) to +0.5V
DATA+, DATA- and CLK+, CLK- .......(V
TT
- 1.2V) to the lower of
(V
TT
+ 1.2V) or +0.5V
MODEN, RTEN,
PWC+, and PWC- .............(V
EE
- 0.5V) to +0.5V
MODSET and BIASSET Voltage .......(V
EE
- 0.5V) to (V
EE
+ 1.5V)
MOD and BIAS Voltage .............................(V
EE
+ 1.0V) to +0.5V
MODN1 and MODN2 Voltage ...............................-0.5V to +0.5V
Operating Junction Temperature Range ...........-55°C to +150°C
Storage Temperature Range .............................-55°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Current into DATA+, DATA-, CLK+, CLK-
(V
TT
= 0V)....................................................-24mA to +30.5mA
Current into DATA+, DATA-, CLK+, CLK-
(V
TT
= -1.3V) ..................................................-24mA to +24mA
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.
DC ELECTRICAL CHARACTERISTICS
(V
EE
= -4.9V to -5.5V ±6%, T
A
= -40°C to +85°C. Typical values are at V
EE
= -5.2V, I
BIAS
= 16.7mA, I
MOD
= 83.3mA, T
A
= +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Power-Supply Voltage
Power-Supply Current
Single-Ended Input Resistance
Bias Current-Setting Range
Bias Current-Setting Error
Bias Sensing Resistor
Bias Current Temperature
Stability
Bias Off-Current
MODEN
and
RTEN
Input High
MODEN
and
RTEN
Input Low
Power-Supply Rejection Ratio
SIGNAL INPUT FOR V
TT
= 0
Single-Ended Input
(DC-Coupled)
Single-Ended Input
(AC-Coupled)
V
IS
V
IS
At high
At low
At high
At low
-1.00
0.075
-0.400
0
-0.15
0.400
-0.075
V
V
V
IH
V
IL
PSRR
f
≤
10MHz, 100mV
P-P
(Note 8)
50
R
BIAS
I
BIAS
= 40mA (Note 2)
I
BIAS
= 1mA
BIASSET
≤
(V
EE
+ 0.4V)
V
EE
+
2.0
V
EE
+
0.8
I
BIAS
SYMBOL
V
EE
I
EE
Excluding bias and modulation current
Input to V
TT
I
BIAS
defined in Figure 3
Bias current = 40mA, T
A
= +25°C
40
1
-10
6.7
-480
-200
0.05
7.5
CONDITIONS
MIN
-5.5
TYP
-5.2
106
50
MAX
-4.9
140
60
40
+10
8.3
+480
UNITS
V
mA
Ω
mA
%
Ω
ppm/°C
mA
V
V
dB
2
_______________________________________________________________________________________
10.7Gbps EAM Driver
DC ELECTRICAL CHARACTERISTICS (continued)
(V
EE
= -4.9V to -5.5V ±6%, T
A
= -40°C to +85°C. Typical values are at V
EE
= -5.2V, I
BIAS
= 16.7mA, I
MOD
= 83.3mA, T
A
= +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Differential Input Swing
(DC-Coupled)
Differential Input Swing
(AC-Coupled)
SIGNAL INPUT FOR V
TT
= -1.3V
Input Common Mode
Single-Ended Input
Differential Input Swing
V
ICM
V
IS
V
ID
At high
At low
-1.225
-1.800
0.3
-1.3
-0.800
-1.375
2.0
V
V
V
P-P
SYMBOL
V
ID
V
ID
CONDITIONS
MIN
0.3
0.3
TYP
MAX
2.0
1.6
UNITS
V
P-P
V
P-P
MAX3935
†
AC ELECTRICAL CHARACTERISTICS
(V
EE
= -4.9V to -5.5V ±6%, T
A
= -40°C to +85°C. Typical values are at V
EE
= -5.2V, I
BIAS
= 16.7mA, I
MOD
= 83.3mA, T
A
= +25°C,
unless otherwise noted.) (Notes 1, 4, 5)
PARAMETER
Input Data Rates
Input Return Loss
Modulation Current-Setting
Range
Modulation Current-Setting Error
Modulation Sensing Resistor
Modulation Current Temperature
Stability
Modulation Off-Current
Output Back Termination
Resistor
Output Edge Speed
Setup/Hold-Time
Pulse-Width Adjustment Range
Pulse-Width Stability
Pulse-Width Control Input
Range
t
R
, t
F
t
SU
, t
HD
Z
L
= 50Ω, 20% to 80% (Note 3)
Figure 2 (Notes 2, 3)
Z
L
= 50Ω, at 10Gbps (Notes 2, 3)
PWC+ and PWC- open (Notes 2, 3)
For PWC+ and PWC-
-6
V
EE
V
EE
+
1.0
25
±60
+6
V
EE
+
2.0
R
MOD
I
MOD
= 100mA (Note 2)
I
MOD
= 20mA
MODSET
≤
(V
EE
+ 0.4V)
63.8
75.0
34
RL
IN
I
MOD
SYMBOL
NRZ (Note 2)
f
≤
15GHz (Notes 2, 6)
I
MOD
defined in Figure 3 (Note 7)
T
A
= +25°C (Note 9)
20
-10
2.7
-550
-200
0.1
86.3
3.0
CONDITIONS
MIN
TYP
10.7
15
100
+10
3.3
+550
MAX
UNITS
Gbps
dB
mA
%
Ω
ppm/°C
mA
Ω
ps
ps
ps
ps
V
_______________________________________________________________________________________
3
10.7Gbps EAM Driver
MAX3935
†
AC ELECTRICAL CHARACTERISTICS (continued)
(V
EE
= -4.9V to -5.5V ±6%, T
A
= -40°C to +85°C. Typical values are at V
EE
= -5.2V, I
BIAS
= 16.7mA, I
MOD
= 83.3mA, T
A
= +25°C,
unless otherwise noted.) (Notes 1, 4, 5)
PARAMETER
Output Overshoot/Undershoot
Driver Random Jitter
Driver Deterministic Jitter
SYMBOL
δ
(Note 3)
(Note 3)
(Note 5)
CONDITIONS
MIN
TYP
1
0.75
11
MAX
UNITS
%
ps
RMS
ps
P-P
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Specifications at -40°C are guaranteed by design and characterization.
Guaranteed by design and characterization.
Measured using a 10.7Gbps repeating 0000 0000 1111 1111 pattern.
AC characterization performed using the circuit in Figure 1.
Measured using a 10.7Gbps 2
13
-1 PRBS with eighty zeros + eighty ones input data pattern.
For both data inputs (DATA+, DATA-) and clock inputs (CLK+, CLK-).
Load impedance is 50Ω in parallel with an internal 75Ω termination.
PSRR = 20
×
log
10
(V
NOISE (ON VCC)
/(∆I
MOD
✕
30Ω)). Excludes the effect of the external op amp.
For 40mA
≤
I
MOD
≤
100mA.
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
OPTICAL EYE DIAGRAM
(I
MOD
= 100mA, 2
13
- 1 +80CID)
MAX3935 toc01
ELECTRICAL EYE DIAGRAM
(I
MOD
= 100mA, 2
13
- 1 +80CID)
MAX3935 toc02
ELECTRICAL EYE DIAGRAM
(I
MOD
= 20mA, 2
13
- 1 +80CID)
MAX3935 toc03
14ps/div
13ps/div
13ps/div
4
_______________________________________________________________________________________
10.7Gbps EAM Driver
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT (I
EE
) vs. TEMPERATURE
(EXCLUDES BIAS AND MODULATION CURRENTS)
MAX3935 toc04
MAX3935
†
PULSE-WIDTH DISTORTION
vs. TEMPERATURE
MAX3935 toc05
TYPICAL DISTRIBUTION OF RISE TIME
60
PERCENT OF UNITS (%)
50
40
30
20
10
0
MAX3935 toc06
150
140
130
SUPPLY CURRENT (mA)
120
110
100
90
80
70
60
50
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
2.5
20mA
PULSE-WIDTH DISTORTION (ps)
2.0
100mA
1.5
1.0
0.5
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
32
33
34
35
36
37
38
RISE TIME (ps)
PULSE WIDTH vs. R
PWC
TYPICAL DISTRIBUTION OF FALL TIME
MAX3935 toc07
2000
810
PULSE WIDTH OF POSITIVE PULSE (ps)
790
770
750
730
710
690
1600
R
PWC-
(Ω)
1200
800
400
0
MAX3935 toc08
MODULATION VOLTAGE vs. V
MODREF
PULSE WIDTH OF NEGATIVE PULSE (ps)
MAX3935 toc09
3.5
3.0
MODULATION VOLTAGE (V)
2.5
2.0
1.5
1.0
0.5
0
0
0.05
0.10
0.15
0.20
0.25
60
PERCENT OF UNITS (%)
50
40
30
20
10
0
32
33
34
35
36
37
38
FALL TIME (ps)
0
400
800
1200
1600
2000
R
PWC+
(Ω)
0.30
V
MODREF
(V)
BIAS VOLTAGE (50Ω) LOAD vs. V
BIASREF
MAX3935 toc10
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
83.3mA
55
50
PSRR (dB)
45
40
35
30
25
20
0.01
0.1
1
10
100
1000 10,000
20mA
100mA
MAX3935 toc11
1.4
1.2
BIAS VOLTAGE (V)
1.0
0.8
0.6
0.4
0.2
0
0
0.05
0.10
0.15
V
BIASREF
(V)
0.20
0.25
60
0.30
FREQUENCY (kHz)
_______________________________________________________________________________________
5
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