19-2717; Rev 6; 6/11
Compact 155Mbps to 4.25Gbps
Limiting Amplifier
MAX3748
General Description
Features
The MAX3748 multirate limiting amplifier functions as a
data quantizer for SONET, Fibre Channel, and Gigabit
Ethernet optical receivers. The amplifier accepts a wide
range of input voltages and provides constant-level
current-mode logic (CML) output voltages with con-
trolled edge speeds.
♦ SFP Reference Design Available
♦ 16-Pin TQFN Package with 3mm x 3mm Footprint
♦ Single 3.3V Supply Voltage
♦ 86ps Rise and Fall Time
♦ Loss of Signal with Programmable Threshold
♦ RSSI Interface (with MAX3744 TIA)
♦ Output Disable
A received-signal-strength indicator (RSSI) is available
when the MAX3748 is combined with the MAX3744 SFP
transimpedance amplifier (TIA). A receiver consisting of
the MAX3744 and the MAX3748 can provide up to
19dB RSSI dynamic range. Additional features include
a programmable loss-of-signal (LOS) detect, an option-
al disable function (DISABLE), and an output signal
polarity reversal (OUTPOL). Output disable can be
used to implement squelch.
♦ Polarity Select
♦ 8.7ps
Deterministic Jitter (4.25Gbps)
P-P
Ordering Information
The combination of the MAX3748 and the MAX3744
allows for the implementation of all the small-form-factor
SFF-8472 digital diagnostic specifications using a stan-
dard 4-pin TO-46 header. The MAX3748 is packaged in
a 3mm x 3mm, 16-pin thin QFN package with an
exposed pad.
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 TQFN-EP**
16 TQFN-EP**
MAX3748HETE#G16*
MAX3748ETE
H = hybrid lead-free package. *See Detailed Description for
more information. The MAX3748H is the MAX3748 in a hybrid
lead-free package.
Applications
Gigabit Ethernet SFF/SFP Transceiver Modules
Fibre Channel SFF/SFP Transceiver Modules
#Denotes a RoHS-compliant device that may include lead that
is exempt under the RoHS requirements.
**EP = Exposed pad.
Functional Diagram and Pin Configuration appear at end of
data sheet.
Multirate OC-3 to OC-48-FEC SFF/SFP
Transceiver Modules
Typical Operating Circuits
SFP OPTICAL RECEIVER
HOST BOARD
SUPPLY FILTER
HOST FILTER
_RX
4-PIN TO HEADER
0.1μF
V
CC
OUTPOL
V
CAZ1 CAZ2
CC
0.1μF
0.1μF
IN+
IN-
OUT+
OUT-
50Ω
50Ω
SERDES
MAX3744 TIA
MAX3748
TH
RSSI
GND
DISABLE LOS
4.7kΩ TO 10kΩ
DS1858
V _HOST
CC
3-INPUT DIAGNOSTIC
MONITOR
R
TH
R1
3kΩ
C1
0.1μF
LOS
Typical Operating Circuits continued at end of data sheet.
________________________________________________________________ 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.