MAX3869(1999) Ver la hoja de datos (PDF) - Maxim Integrated

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MAX3869
(Rev.:1999)

+3.3V, 2.5Gbps SDH/SONET Laser Driver with Current Monitors and APC

Maxim Integrated 

+3.3V, 2.5Gbps SDH/SONET Laser Driver

with Current Monitors and APC

Determine RBIASMAX

Calculate the maximum threshold current (ITH(MAX)) at

TA = +85°C and end of life. Assuming ITH(MAX) =

50mA, the maximum bias current should be:

IBIASMAX = ITH(MAX) + IMOD/2

In this example, IBIASMAX = 68.1mA. The IBIASMAX vs.

RBIASMAX graph in the Typical Operating Characteristics

shows that RBIASMAX should be 3.2kΩ.

Modulation Currents Exceeding 60mA

With a +5V power supply, the headroom voltage for the

MAX3869 is significantly improved. In this case, it is

possible to achieve a modulation current of more than

60mA with AC-coupling, if the junction temperature is

kept below 150°C. The MAX3869 can also be DC-cou-

pled to a laser diode when operating with a +5V sup-

ply; the voltage at OUT+ should be ≥ 2.0V for proper

operation.

Wire Bonding Die

For high current density and reliable operation, the

MAX3869 uses gold metalization. Make connections to

the die with gold wire only, using ball-bonding tech-

niques. Wedge bonding is not recommended. Die-pad

size is 4 mils (100µm) square, and die thickness is 12

mils (300µm) square.

Layout Considerations

To minimize inductance, keep the connections between

the MAX3869 output pins and LD as close as possible.

Optimize the laser diode performance by placing a

bypass capacitor as close as possible to the laser

anode. Use good high-frequency layout techniques

and multilayer boards with uninterrupted ground planes

to minimize EMI and crosstalk.

Laser Safety and IEC 825

Using the MAX3869 laser driver alone does not ensure

that a transmitter design is compliant with IEC 825. 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.

Chip Information

TRANSISTOR COUNT: 1561

SUBSTRATE CONNECTED TO GND

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