MAX3740 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 3.2Gbps SFP VCSEL Driver with Diagnostic Monitors

19-2679; Rev 2; 7/03
3.2Gbps SFP VCSEL Driver with Diagnostic
Monitors
General Description
The MAX3740 is a high-speed VCSEL driver for small-
form-factor (SFF) and small-form-factor pluggable (SFP)
fiber optic LAN transmitters. It contains a bias genera-
tor, a laser modulator, and comprehensive safety fea-
tures. The automatic power control (APC) adjusts the
laser bias current to maintain average optical power
over changes in temperature and laser properties. The
driver accommodates common cathode and differential
configurations.
The MAX3740 operates up to 3.2Gbps. It can switch up
to 15mA of laser modulation current and source up to
15mA of bias current. Adjustable temperature compen-
sation is provided to keep the optical extinction ratio
within specifications over the operating temperature
range. The MAX3740 interfaces with the Dallas DS1858
to meet SFF-8472 timing and diagnostic requirements.
The MAX3740 accommodates various VCSEL pack-
ages, including low-cost TO-46 headers.
The MAX3740 safety circuit detects faults that could
cause hazardous light levels and disables the VCSEL
output. The safety circuits are compliant with SFF and
SFP multisource agreements (MSA).
The MAX3740 is available in a compact 4mm ✕ 4mm,
24-pin thin QFN package and operates over the -40°C
to +85°C temperature range.
Applications
Multirate (1Gbps to 3.2Gbps) SFP/SFF Modules
Gigabit Ethernet Optical Transmitters
Fibre Channel Optical Transmitters
Infiniband Optical Transmitters
Features
o Supports all SFF-8472 Digital Diagnostics
o 2mA to 15mA Modulation Current
o 1mA to 15mA Bias Current
o Optional Peaking Current to Improve VCSEL Edge
Speed
o Supports Common Cathode and Differential
Configuration
o Automatic Power Control
o Safety Circuits Compliant with SFF and SFP
MSAs
o 4mm ✕ 4mm 24-Pin Thin QFN Package
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX3740ETG -40°C to +85°C 24 Thin QFN (4mm ✕ 4mm)
Typical Application Circuit
+3.3V
FAULT
VCC
4.7kΩ
0.1µF
0.1µF
RTC^†
RBIASSET
TX_DISABLE
SQUELCH
MAX3740
IN+
FAULT
PWRMON
MODSET
REF
BIASMON
COMP
IN-
MD
BIAS
TC1
TC2
BIASSET
GND
PEAKSET
OUT+
OUT-
RPEAKSET^†
IN1
OUT1
MON2
H0
DS1858
H1 _MON1
L0 L1
RBIASMON
0.047µF
0.01µF
0.01µF
50Ω
L1*
CF^†
RF^†
†_{OPTIONAL COMPONENT}
*FERRITE BEAD
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1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.