Rainbow Electronics MAX3646 - Manual (Page 13)

Layout Considerations
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
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.
Laser Safety and IEC 825
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.
Exposed-Pad (EP) Package
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 Maxim
Application Note HFAN-08.1: Thermal Consideration
for QFN and Other Exposed-Pad Packages at
www.maxim-ic.com for additional information.
Chip Information
TRANSISTOR COUNT: 7884
PROCESSS: SiGe/bipolar
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
______________________________________________________________________________________ 13
MAX3646
IN+
IN-
REPRESENTS A CONTROLLED-IMPEDANCE TRANSMISSION LINE.
V
CC
SHUTDOWN
+3.3V
OPTIONAL SHUTDOWN
CIRCUITRY
+3.3V
15Ω
10Ω
OUT-
OUT+
BIAS
MD
BC_MON APCFIL
T1
APCFIL
T2
GND APCSET MODSET
TX_DISABLE
TX_F
AUL
T
+3.3V
CDR
C APC
R
PC_MON
C
MD
0.01µF
FERRITE BEAD
PC_MON
R
BC_MON R
MODSET R
APCSET
MODBCOMP
MODTCOMP
TH_TEMP
R TH_TEMP
R
MODTCOMP
R
MODBCOMP
0.1µF
0.1µF
Typical Application Circuit