MAX3656 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – 155Mbps to 2.5Gbps Burst-Mode Laser Driver

19-2790; Rev 1; 5/04
155Mbps to 2.5Gbps Burst-Mode
Laser Driver
General Description
The MAX3656 is a burst-mode laser driver that oper-
ates at data rates from 155Mbps up to 2.5Gbps. The
laser driver accepts either positive-referenced emitter-
coupled logic (PECL) or current-mode logic (CML) data
inputs and provides bias and modulation current for the
laser diode. The device can switch the laser diode from
a completely dark (off) condition to a full (on) condition
(with proper bias and modulation currents) in less than
2ns. The MAX3656 incorporates DC-coupling between
laser driver and laser diode and operates with a single-
supply voltage as low as +3.0V.
A digital automatic power-control (APC) loop is provided
to maintain the average optical power over the full tem-
perature range and lifetime. The APC loop is functional
for a minimum burst on-time of 576ns and minimum
burst off-time of 96ns, with no limit on the maximum
burst on- or off-time. A fail monitor is provided to indi-
cate when the APC loop can no longer maintain the
average power. The MAX3656 can be configured for
nonburst-mode applications (continuous mode) by con-
necting burst enable (BEN) high. For power saving, the
MAX3656 provides enabling and disabling functionality.
The modulation current can be set from 10mA to 85mA
and the bias current can be set from 1mA to 70mA.
The MAX3656 is packaged in a small, 24-pin, 4mm ✕
4mm thin QFN package and consumes only 132mW
(typ), excluding bias and modulation currents.
Applications
Fiber-to-the-Home (FTTH) and Fiber-to-the-
Business (FTTB) Broadband Access Systems
Passive Optical Network (PON) Transmitters
APON, EPON, and GPON Upstream Transmitters
Pin Configuration
TOP VIEW
24 23 22 21 20 19
VCC 1
18 V_CC
IN+ 2
17 OUT-
IN- 3
VCC ₄
MAX3656
16 OUT+
15 VCC
BEN+ 5
14 BIAS+
BEN- 6
13 BIAS-
7 8 9 10 11 12
Features
o Multirate Operation from 155Mbps to 2.5Gbps
o Burst Enable/Disable Delay <2ns
o Burst On-Time of 576ns to Infinity
o Infinite Bias-Current Hold Time Between Bursts
o DC-Coupled Operation with Single +3.3V Power
Supply
o 40mA Typical Supply Current
o Programmable Bias Current from 1mA to 70mA
o Programmable Modulation Current from 10mA
to 85mA
o Automatic Average Power Control with Failure
Monitor (No C_APC Capacitor Needed)
o APC Loop Initialization ≤3 Bursts
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
PKG
CODE
MAX3656E/D
—
Dice*
—
MAX3656ETG -40°C to +85°C 24 Thin QFN-EP** T2444-1
MAX3656ETG+ -40°C to +85°C 24 Thin QFN-EP** —
+ Denotes lead-free package.
*Dice are designed to operate from T_J = -40°C to +120°C, but
are only tested and guaranteed at T_A = +25°C.
**EP = Exposed pad.
Functional Diagram appears at end of data sheet.
Typical Application Circuit
VCC
VCC
SERIAL
DATA
SOURCE
IN+
100Ω
IN-
OUT-
OUT+
MAX3656 _BIAS+
BURST
CONTROL
BEN+
100Ω
VCC
BIAS-
MD
BEN-
THIN QFN
**EXPOSED PAD IS CONNECTED TO GND
________________________________________________________________ Maxim Integrated Products 1
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