MAX3738 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 1Gbps to 2.7Gbps SFF/SFP Laser Driver with Extinction Ratio Control

19-3162; Rev 0; 1/04
1Gbps to 2.7Gbps SFF/SFP Laser Driver with
Extinction Ratio Control
General Description
The MAX3738 is a +3.3V laser driver designed for mul-
tirate transceiver modules with data rates from 1Gbps
to 2.7Gbps. Lasers can be DC-coupled to the
MAX3738 for reduced component count and ease of
multirate operation.
Laser extinction ratio control (ERC) combines the features
of automatic power control (APC), modulation compensa-
tion, and built-in thermal compensation. The APC loop
maintains constant average optical power. Modulation
compensation increases the modulation current in pro-
portion to the bias current. These control loops, com-
bined with thermal compensation, maintain a constant
optical extinction ratio over temperature and lifetime.
The MAX3738 accepts differential data input signals.
The wide 5mA to 60mA (up to 85mA AC-coupled) mod-
ulation current range and up to 100mA bias current
range, make the MAX3738 ideal for driving FP/DFB
lasers in fiber optic modules. External resistors set the
required laser current levels. The MAX3738 provides
transmit disable control (TX_DISABLE), single-point
fault tolerance, bias-current monitoring, and photocur-
rent monitoring. The device also offers a latched failure
output (TX_FAULT) to indicate faults, such as when the
APC loop is no longer able to maintain the average
optical power at the required level. The MAX3738 is
compliant with the SFF-8472 transmitter diagnostic and
SFP MSA timing requirements.
The MAX3738 is offered in a 4mm x 4mm, 24-pin thin
QFN package and operates over the extended -40°C to
+85°C temperature range.
Features
♦ Single +3.3V Power Supply
♦ 47mA Power-Supply Current
♦ 85mA Modulation Current
♦ 100mA Bias Current
♦ Automatic Power Control (APC)
♦ Modulation Compensation
♦ On-Chip Temperature Compensation
♦ Self-Biased Inputs for AC-Coupling
♦ Ground-Referenced Current Monitors
♦ Laser Shutdown and Alarm Outputs
♦ Enable Control and Laser Safety Feature
Ordering Information
PART
MAX3738ETG
TEMP
RANGE
-40°C to 85°C
PIN-
PACKAGE
24 Thin QFN
PKG
CODE
T2444-1
Typical Application Circuit appears at end of data sheet.
Pin Configuration
Applications
Multirate OC-24 to OC-48 FEC Transceivers
Gigabit Ethernet SFF/SFP and GBIC
Transceivers
1Gbps/2Gbps Fibre Channel SFF/SFP and GBIC
Transceivers
TOP VIEW
24 23 22 21 20 19
MODTCOMP 1
18 MD
V_CC 2
17 VCC
IN+ 3
IN- 4
MAX3738
16 OUT+
15 OUT-
V_CC 5
14 VCC
TX_DISABLE 6
13 BIAS
7 8 9 10 11 12
THE EXPOSED PADDLE MUST BE SOLDERED TO SUPPLY
GROUND ON THE CIRCUIT BOARD.
________________________________________________________________ Maxim Integrated Products 1
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1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.