MAX3262 Maxim, MAX3262 Datasheet - Page 5

• Manufacturer Part Number: MAX3262
• Description: Single +5V / Fully Integrated / 155Mbps Laser Diode Driver
• Manufacturer: Maxim

The MAX3263 laser driver has three main sections: a
reference generator with temperature compensation, a
laser bias block with automatic power control, and a
modulation driver (Figure 1).
The reference generator provides temperature-com-
pensated biasing and a voltage-reference output. The
voltage reference is used to program the current levels
of the high-speed modulation driver, laser diode, and
PIN (p+, intrinsic, n-) monitor diode.
The laser bias block sets the bias current in the laser
diode and maintains it above the threshold current. A
Figure 1. Functional Diagram
_______________Detailed Description
SLWSTRT
ENB+
VCCA
GNDB
ENB-
VCCB
GNDA
VIN+
VIN-
MAX3263
GENERATOR
REFERENCE
BANDGAP
MAIN
_______________________________________________________________________________________
BIAS
20 x I
Single +5V, Fully Integrated,
155Mbps Laser Diode Driver
MODSET
TRANSCONDUCTANCE
AMPLIFIER
40 x I
BIASSET
current-controlled current source (current mirror) pro-
grams the bias, with IBIASSET as the input. The mirror’s
gain is approximately 40 over the MAX3263’s input
range. Keep the output voltage of the bias stage above
2.2V to prevent saturation.
The modulation driver consists of a high-speed input
buffer and a common-emitter differential output stage.
The modulation current mirror sets the laser modulation
current in the output stage. This current is switched
between the OUT+ and OUT- ports of the laser driver.
The modulation current mirror has a gain of approximately
20. Keep the voltages at OUT+ and OUT- above 2.2V to
prevent saturation.
+2.6V
IPINSET
V
CC
x 3/5
COMPARATOR
R
PINSET
1 x I
PINSET
I
FAILOUT
OUT+
OUT-
BIASOUT
IPIN
V
COMPEN-
SATION
CC
BIAS
LASER
PHOTO-
DIODE
CAPACITOR
STABILITY
LOOP-
0.1 F
5