19-2717; Rev 2; 2/04
Compact 155Mbps to 3.2Gbps
Limiting Amplifier
General Description
Features
The MAX3748/MAX3748A multirate limiting amplifier func-
tions 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 QFN Package with 3mm ✕ 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/MAX3748A is combined with the
MAX3744 SFP transimpedance amplifier (TIA). A receiver
consisting of the MAX3744* and the MAX3748/
MAX3748A can provide up to 19dB RSSI dynamic range.
Additional features include a programmable loss-of-signal
(LOS) detect, an optional disable function (DISABLE),
and an output signal polarity reversal (OUTPOL). Output
disable can be used to implement squelch.
✕ Polarity Select
✕ 8.5ps
Deterministic Jitter (3.2Gbps)
P-P
Ordering Information
The combination of the MAX3748/MAX3748A and the
MAX3744 allows for the implementation of all the small-
form-factor SFF-8472 digital diagnostic specifications
using a standard 4-pin TO-46 header. The MAX3748/
MAX3748A is packaged in a 3mm ✕ 3mm 16-pin QFN
package with an exposed pad.
PIN-
PACKAGE
PACKAGE
CODE
PART
MAX3748ETE
TEMP RANGE
-40°C to +85°C 16 QFN-EP*
T1633-3
T1633-3
MAX3748AETE -40°C to +85°C 16 QFN-EP*
*Future product—contact factory for availability.
*EP = Exposed pad.
Applications
Gigabit Ethernet SFF/SFP Transceiver Modules
Functional Diagram and Pin Configuration appear at end of
data sheet.
Fibre Channel SFF/SFP Transceiver Modules
Multirate OC-3 to OC-48-FEC SFF/SFP
Transceiver Modules
Typical Operating Circuits
SFP OPTICAL RECEIVER
HOST BOARD
SUPPLY FILTER
HOST FILTER
_RX
0.1µF
4-PIN TO HEADER
V
CC
OUTPOL
V
CAZ1 CAZ2
CC
0.1µF
0.1µF
IN+
IN-
OUT+
OUT-
50Ω
50Ω
SERDES
MAX3744 TIA*
MAX3748/
MAX3748A
RSSI TH
GND
DISABLE LOS
4.7kΩ TO 10kΩ
V
_HOST
CC
DS1858
R
TH
3-INPUT DIAGNOSTIC
MONITOR
LOS
R1
3kΩ
C1
0.1µF
*FUTURE PRODUCT.
Typical Operating Circuits continued at end of data sheet.
________________________________________________________________ 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.