MAX3740A_10 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – 3.2Gbps SFP VCSEL Driver with Diagnostic Monitors

19-3118; Rev 3; 1/10
3.2Gbps SFP VCSEL Driver with Diagnostic
Monitors
General Description
The MAX3740A 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 MAX3740A 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 com-
pensation is provided to keep the optical extinction
ratio within specifications over the operating tempera-
ture range. The MAX3740A interfaces with the Dallas
DS1858 to meet SFF-8472 timing and diagnostic
requirements. The MAX3740A accommodates various
VCSEL packages, including low-cost TO-46 headers.
The MAX3740A 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 MAX3740A 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
♦ Supports all SFF-8472 Digital Diagnostics
♦ 2mA to 15mA Modulation Current
♦ 1mA to 15mA Bias Current
♦ Optional Peaking Current to Improve VCSEL Edge
Speed
♦ Supports Common Cathode and Differential
Configuration
♦ Automatic Power Control
♦ Safety Circuits Compliant with SFF and SFP
MSAs
♦ 4mm ✕ 4mm, 24-Pin Thin QFN Package
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX3740AETG
-40°C to +85°C 24 Thin QFN-EP*
MAX3740AETG+ -40°C to +85°C 24 Thin QFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Application Circuit
+3.3V
TX_DISABLE
SQUELCH
VCC
FAULT
PWRMON
MODSET
4.7kΩ^†
RMODSET
0.1μF
IN+
MAX3740A
REF
COMP
IN-
MD
0.1μF
TC1
BIAS
RTC†
0.047μF
RBIASSET
TC2
0.01μF
BIASSET
OUT+
OUT-
GND PEAKSET
BIASMON ^0.01μF
50Ω
RPEAKSET†
RBIASMON
RPWRSET
L1*
CF†
RF†
†_{OPTIONAL COMPONENT}
*FERRITE BEAD
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.