MAX3656(2010) Ver la hoja de datos (PDF) - Maxim Integrated

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componentes Descripción

Fabricante

MAX3656
(Rev.:2010)

155Mbps to 2.5Gbps Burst-Mode Laser Driver

Maxim Integrated 

155Mbps to 2.5Gbps Burst-Mode

Laser Driver

LVTTL OR LVCMOS HIGH

LVTTL OR LVCMOS LOW

VCC

R3 = 5kΩ

R4 = 3kΩ

VCC

R5 = 5kΩ

IN+

IN-

BEN+

BEN-

MAX3656

R6 = 9kΩ

Figure 7. Single-Ended LVTTL or LVCMOS Biasing for Burst

Enable

Applications Information

Running Burst Enable Single-Ended

With PECL signal levels, for single-ended operation of

burst enable, connect the BEN+ to the burst-enable

control. Connect a resistor (R1) from VCC to BEN- and

resistor (R2) from BEN- to ground. The parallel combi-

nation of R1 and R2 should be less than 1kΩ. Choose

the values of R1 and R2 to set the common-mode volt-

age in the range defined in the Electrical

Characteristics table (see Figure 6).

With LVTTL or LVCMOS signal levels, for single-ended

operation of burst enable connect a 3kΩ (R4) resistor

from the burst-enable signal to BEN+. Connect a 5kΩ

(R3) resistor from VCC to BEN+. Connect a 5kΩ resistor

(R5) from VCC to BEN- and a 9kΩ resistor (R6) from

BEN- to ground. For typical LVTTL or LVCMOS specifi-

cations of VCC to 2.0V for a high and 0.8V to 0V for a

low, the LVTTL or LVCMOS sources a maximum of

75µA and sinks a maximum of 500µA. See Figure 7 for

setting up the single-ended LVTTL or LVCMOS biasing

for burst enable.

Layout Considerations

To minimize inductance, keep the connections between

the MAX3656 output pins and laser diode as close as

possible. Place a bypass capacitor as close as possi-

ble to each VCC connection. Take extra care to mini-

mize stray parasitic capacitance on the BIAS and MD

pins. Use good high-frequency layout techniques and

multilayer boards with uninterrupted ground planes to

minimize EMI and crosstalk.

Laser Safety and IEC825

Using the MAX3656 laser driver alone does not ensure

that a transmitter design is compliant with IEC825. The

entire transmitter circuit and component selections

must be considered. Each user must determine the

level of fault tolerance required by the application, rec-

ognizing that Maxim products are neither designed nor

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 in which the failure of a Maxim product

could create a situation where personal injury or death

can occur.

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