MAX3646ETG+T Maxim Integrated Products, MAX3646ETG+T Datasheet - Page 13

• Manufacturer Part Number: MAX3646ETG+T
• Description: IC LSR DRVR 622MBPS 3.63V 24TQFN
• Manufacturer: Maxim Integrated Products
• Type: Laser Diode Driver (Fiber Optic)r

Specifications of MAX3646ETG+T

• Data Rate: 622Mbps
• 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: 24-TQFN Exposed Pad
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Maxim Laser Drivers with Laser Diodes for more informa-
tion on AC-coupling laser drivers to laser diodes.
For compliance:
The APC loop filter capacitor (C
to balance the requirements for fast turn-on and mini-
mal 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 MAX3646 is designed so turn-on time is faster than
1ms for most laser gain values (η x ρ
smaller value of C
balance between turn-on time and low-frequency 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 MAX3646 laser driver. If dice are used,
replace package parasitic elements with bondwire par-
asitic elements.
To minimize loss and crosstalk, keep the connections
between the MAX3646 output and the laser diode as
short as possible. Use good high-frequency layout
V
C
MD
OUT+
APC
, from the MD pin to ground:
(µF) ≅ 68 / (f
= V
Laser Driver with Extinction Ratio Control
CC
______________________________________________________________________________________
APC
- I
C
MD
MOD
3dB
reduces turn-on time. Careful
≅ C
Layout Considerations
/ 2 x (R
(kHz) x (η x
APC
APC
/ 4
Interface Models
D
Determine C
+ R
) must be selected
MON
L
ρ MON
) ≥ 0.75V
). Choosing a
155Mbps to 622Mbps SFF/SFP
)
1.1
APC
techniques and multilayer boards with uninterrupted
ground plane to minimize EMI and crosstalk. Circuit
boards should be made using low-loss dielectrics. Use
controlled-impedance lines for data inputs, as well as
the module output.
Using the MAX3646 laser driver alone does not ensure
that a transmitter design is IEC 825 compliant. The
entire transmitter circuit and component selections must
be considered. Each customer must determine the level
of fault tolerance required by their application, recogniz-
ing that Maxim products are not designed or authorized
for use as components in systems intended for surgical
implant into the body, for applications intended to sup-
port or sustain life, or for any other application where the
failure of a Maxim product could create a situation
where personal injury or death may occur.
The exposed pad on the 24-pin QFN provides a very low
thermal resistance path for heat removal from the IC. The
pad is also electrical ground on the MAX3646 and should
be soldered to the circuit board ground for proper ther-
mal and electrical performance. Refer to Application Note
862: HFAN-08.1: Thermal Consideration of QFN and
Other Exposed-Paddle Packages at
for additional information.
TRANSISTOR COUNT: 7884
PROCESSS: SiGe/BIPOLAR
Exposed-Pad (EP) Package
Laser Safety and IEC 825
Chip Information
www.maxim-ic.com
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