MAX3737ETJ+ Maxim Integrated Products, MAX3737ETJ+ Datasheet - Page 12

• Manufacturer Part Number: MAX3737ETJ+
• Description: IC LSR DRVR 2.7GBPS 3.63V 32TQFN
• Manufacturer: Maxim Integrated Products
• Type: Laser Diode Driver (Fiber Optic)r

Specifications of MAX3737ETJ+

• Data Rate: 2.7Gbps
• Number Of Channels: 1
• Voltage - Supply: 2.97 V ~ 3.63 V
• Current - Supply: 47mA
• Current - Modulation: 85mA
• Current - Bias: 100mA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-WFQFN Exposed Pad
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

An external resistor at the MODBCOMP pin sets current
proportional to I
pin can turn off the interaction between I
If I
maintain the extinction ratio at elevated temperature,
the required compensation factor is:
A threshold for additional temperature compensation
can be set with a programming resistor at the
TH_TEMP pin:
The temperature coefficient of thermal compensation
above T
COMP pin open disables additional thermal compensation:
The minimum voltage at the OUT+ and OUT- pins is
0.7V.
For:
V
R
R
For compliance:
Multirate Laser Driver with Extinction
Ratio Control
12
V
DIODE
L
D
OUT
—Diode bias point resistance (5Ω typ)
—Series matching resistor (20Ω typ)
MOD
______________________________________________________________________________________
+
=
T
I
—Diode bias point voltage (1.2V typ)
MOD
TH
TH
must be increased from I
V
TC
CC
Current Compliance (I
I
I
MODT
MODT
=
is set by R
K
-
=
=
- 70
V
=
I
0 5
MODS
DIODE
I
MODS
.
BIAS
1000
=
=
°
C
+
K
TC
0
-
=
=
. Open circuiting the MODBCOMP
+
R
I
+
MODTCOMP
MOD
+
268
I
I
×
MOD
9 2
BIAS
MODTCOMP
R
K
.
1700
(
MODBCOMP
k
T T
1
×
Ω
×
×
2
2
-
1 45
I
-
-
(
BIAS
TH
R
R
+
.
I
I
D
MODSET
MOD
BIAS
V
R
)
+
M
REF
TH TEMP
(
R
|
|
. Leaving the MODT-
k
+
Ω
L
1
1
Ω
T T
T T
)
I
_
MODT
MOD1
≤
)
>
±
-
mA
MOD
10%
°
I
BIAS
C
TH
TH
BIAS
DC-Coupled
±
° ±
to I
C
10
×
≤ ≤ 60mA),
and I
R
%
MOD2
10
L
≥
%
MOD
. 0 7
V
to
:
For applications requiring modulation current greater
than 60mA, headroom is insufficient for proper opera-
tion of the laser driver if the laser is DC-coupled. To
avoid this problem, the MAX3737’s modulation output
can be AC-coupled to the cathode of a laser diode. An
external pullup inductor is necessary to DC-bias the
modulation output at V
laser forward voltage from the output circuitry and
allows the output at OUT+ to swing above and below
the supply voltage (V
MAX3737 modulation current can be programmed up
to 85mA. Refer to Maxim Application Note HFAN 02.0:
Interfacing Maxim’s Laser Drivers to Laser Diodes for
more information on AC-coupling laser drivers to laser
diodes.
For compliance:
The APC loop filter capacitor C
balance the requirements for fast turn-on and minimal
interaction with low frequencies in the data pattern. The
low-frequency cutoff is:
High-frequency noise can be filtered with an additional
cap C
The MAX3737 is designed so that turn-on time is faster
than 1ms for most laser gain values (η
Choosing a smaller value of C
time. Careful balance between turn-on time and low-fre-
quency cutoff may be needed at low data rates for
some values of laser gain.
Figures 6 and 7 show simplified input and output cir-
cuits for the MAX3737 laser driver. If dice are used,
replace package parasitic elements with bondwire par-
asitic elements.
MD
V
OUT
C
Current Compliance (I
from the MD pin to ground:
APC
+
=
(
µ
V
C
F
)
C
≈
-
C
f
3
I
MOD
CC
DB
MD
2
CC
68
. Such a configuration isolates
(
kHz
≈
). When AC-coupled, the
×
C
)
(
APC
R
4
APC
×
D
APC
Interface Models
(
+
Determine C
η
must be selected to
R
×
MOD
reduces turn-on
L
)
ρ
AC-Coupled
MON
≥
> 60mA),
0 75
.
)
✕
1 1
.
ρ
V
MON
APC
).