Layout considerations, Laser safety and iec 825 – Rainbow Electronics MAX3737 User Manual

Page 13

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Layout Considerations

To minimize loss and crosstalk, keep the connections
between the MAX3737 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 MAX3737 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, recognizing
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 support
or sustain life, or for any other application where the fail-
ure of a Maxim product could create a situation where
personal injury or death may occur.

MAX3737

Multirate Laser Driver with Extinction

Ratio Control

______________________________________________________________________________________

13

PC_MON

BC_MON

MC_MON

R

PC_MON

R

BC_MON

R

MC_MON

V

CC

V

CC

MAX3737

COMP

R

Q

S

RS

LATCH

CMOS

SHUTDOWN

TX_FAULT

TX_DISABLE

TTL

OPEN

COLLECTOR

COMP

COMP

EXCESSIVE

MODULATION

CURRENT

V

CC

I

MD

1

V

CC

V

REF

V

REF

V

REF

I

BIAS

82

I

MOD

268

I

MOD

ENABLE

I

BIAS

ENABLE

COUNTER

60ms DELAY

100ns

DELAY

POR AND COUNTER

60ms DELAY

Figure 5. Simplified Safety Circuit

MAX3737

5k

16k

5k

24k

PACKAGE

V

CC

V

CC

0.83nH

0.83nH

0.11pF

0.11pF

V

CC

Figure 6. Simplified Input Structure

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