19-2529; Rev 2; 7/04
2.7Gbps, Low-Power SFP Laser Drivers
General Description
Features
♦ SFP Reference Design Available
The MAX3735/MAX3735A are +3.3V laser drivers for
SFP/SFF applications from 155Mbps up to 2.7Gbps.
The devices accept differential input data and provide
bias and modulation currents for driving a laser. DC-
coupling to the laser allows for multirate applications
and reduces the number of external components. The
MAX3735/MAX3735A are fully compliant with the SFP
MSA timing and the SFF-8472 transmit diagnostic
requirements.
♦ Fully Compliant with SFP and SFF-8472 MSAs
♦ Programmable Modulation Current from 10mA to
60mA (DC-Coupled)
♦ Programmable Modulation Current from 10mA to
85mA (AC-Coupled)
♦ Programmable Bias Current from 1mA to 100mA
An automatic power-control (APC) feedback loop is incor-
porated to maintain a constant average optical power
over temperature and lifetime. The wide modulation cur-
rent range of 10mA to 60mA (up to 85mA AC-coupled)
and bias current of 1mA to 100mA make this product
ideal for driving FP/DFB laser diodes in fiber-optic mod-
ules. The resistor range for the laser current settings is
optimized to interface with the DS1858 SFP controller IC.
♦ Edge Transition Times <51ps
♦ 27mA (typ) Power-Supply Current
♦ Multirate 155Mbps to 2.7Gbps Operation
♦ Automatic Average Power Control
♦ On-Chip Pullup Resistor for TX_DISABLE
♦ 24-Pin 4mm × 4mm QFN package
Ordering Information
The MAX3735/MAX3735A provide transmit-disable con-
trol, a single-point latched transmit-failure monitor out-
put, photocurrent monitoring, and bias-current
monitoring to indicate when the APC loop is unable to
maintain the average optical power. The MAX3735A
also features improved multirate operation.
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
Dice*
MAX3735E/D
MAX3735ETG
MAX3735EGG
MAX3735AETG
MAX3735AETG+
24 Thin QFN-EP**
24 QFN-EP**
The MAX3735/MAX3735A come in package and die
form, and operate over the extended temperature
range of -40°C to +85°C.
24 Thin QFN-EP**
24 Thin QFN-EP**
Applications
Gigabit Ethernet SFP/SFF Transceiver Modules
*Dice are designed to operate from -40°C to +85°C, but are
1G/2G Fibre Channel SFP/SFF Transceiver
Modules
tested and guaranteed only at T = +25°C.
**EP = Exposed pad.
+Denotes lead-free package.
A
Multirate OC3 to OC48-FEC SFP/SFF Transceiver
Modules
Pin Configuration appears at end of data sheet.
Typical Application Circuit
+3.3V
OPTIONAL SHUTDOWN
CIRCUITRY
+3.3V
+3.3V
0.01µF
15Ω
0.1µF
OUT-
10Ω
OUT+
IN+
SERDES
0.1µF
OUT+
MAX3735
MAX3735A
IN-
BIAS
FERRITE BEAD
MD
C
MD
DS1858/DS1859
CONTROLLER
IC
H0
H1
C
APC
R
R
BC_MON
PC_MON
MON1
M0N2
M0N3
+3.3V
REPRESENTS A CONTROLLED-IMPEDANCE TRANSMISSION LINE
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.