MAX3766EEP+ Maxim Integrated Products, MAX3766EEP+ Datasheet - Page 11

• Manufacturer Part Number: MAX3766EEP+
• Description: IC LASR DRVR 622MBPS 5.5V 20QSOP
• Manufacturer: Maxim Integrated Products
• Type: Laser Diode Driver (Fiber Optic)r

Specifications of MAX3766EEP+

• Data Rate: 622Mbps
• Number Of Channels: 1
• Voltage - Supply: 4.5 V ~ 5.5 V
• Current - Supply: 25mA
• Current - Modulation: 60mA
• Current - Bias: 80mA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QSOP
• Mounting Type: Surface Mount
• Operating Supply Voltage: 5 V
• Supply Current: 25 mA
• Maximum Operating Temperature: + 85 C
• Maximum Power Dissipation: 590 mW
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 6. Reset Pulse Generator
If PC board space is not a constraint, Maxim recom-
mends enabling the transmitter with a reset-pulse gen-
erator, such as the MAX809, which generates a reset
signal after V
ensures that the transmitter starts correctly, even if the
supply ramps very slowly.
Table 1. Output Voltage Approximation
Automatic Power Control and Safety Shutdown
VARIABLE
MAX809MEUR-T
V
V
OUT(MIN)
V
ENABLE
CC(MIN)
LASER
I
OUT
R
R
V
L
t
D
r
OR
L
CC
CC
RESET
reaches 4.5V (Figure 6). This method
V
______________________________________________________________________________________
CC
Approximation for the lowest voltage at the OUT+ pin
Minimum power supply
Laser forward voltage at operating power
Laser dynamic resistance
Laser modulation current
Any damping resistance or line termination in series with the laser
(but not in series with BIAS)
Total series inductance of laser, laser package, and board traces to the
MAX3766
20% to 80% rise time of the laser modulation current, filtered by a
compensation network
622Mbps LAN/WAN Laser Driver with
C
SAFETY
ENABLE
SAFETY
*IN LATCHED SHUTDOWN
CONFIGURATION
MAX3766*
DESCRIPTION
Select a communications-grade laser with a rise time of
0.5ns or better for 622Mbps applications. The voltage
swing at the OUT+ pin affects the output waveform,
and is largely determined by the laser resistance,
inductance, and modulation current. To obtain the
MAX3766’s AC specifications, the output voltage at
OUT+ must remain above V
An approximation for the minimum voltage at OUT+ is
given by the following equation (Table 1):
Select a laser that meets the output voltage criteria. A
high-efficiency laser requires low modulation current
and generates low voltage swing at OUT+. Laser pack-
age inductance can be reduced by trimming leads.
Typical package leads have inductance of 25nH per
inch (1nH/mm). A compensation filter network can also
be used to reduce ringing, edge speed, and voltage
swing.
__________________Design Procedure
V
OUT(MIN)
= V
⎛
⎜
⎝
R
CC(MIN)
L
+
CC
R
D
- V
- 2.5V at all times.
+
LASER
t
L
TYPICAL VALUE
r
⎞
⎟
⎠
(20% to 80%)
Select Laser
300ps
30mA
- I
2.2V
4.5V
1.3V
10Ω
6nH
3Ω
(
MOD
)
11