MAX3956 Datasheet, PDF (1/82 Pages) Maxim Integrated Products – Transceiver with DDM and DC-Coupled Laser Interface

MAX3956
11.3Gbps Transceiver with DDM and
DC-Coupled Laser Interface
General Description
The MAX3956 is an 11.3Gbps, highly-integrated, low-
power transceiver with digital diagnostics monitoring
(DDM) designed for next-generation Ethernet transmis-
sion systems. The receiver incorporates a limiting ampli-
fier and loss-of-signal (LOS) circuit. The limiting ampli-
fier features dual-path architecture optimizing the perfor-
mance for signals up to 4.25Gbps and up to 11.3Gbps,
respectively. The transmitter incorporates Maxim’s propri-
etary DC-coupled laser driver interface and closed-loop
control of laser average power. This part is optimized to
enable 0.8W maximum power dissipation target of SFP+
MSA based modules.
The MAX3956 supports differential AC-coupled signaling
with 50Ω termination at Rx input, Rx output, and Tx input.
The Tx output is a DC-coupled 25Ω laser diode interface
with dedicated pins for the laser anode (TOUTA) and the
laser cathode (TOUTC).
An integrated 12-bit analog-to-digital converter (ADC)
is utilized to provide digital monitors of internal/external
temperature, V_CC, and received signal strength indica-
tion (RSSI). The MAX3956’s digital monitors and the use
of a 2-wire or 3-wire slave interface enables configuration
through a digital-only microcontroller (µC).
The MAX3956 operates from a single +3.3V supply and
over a -40°C to +95°C temperature range and is available
in a standard 5mm x 5mm, 32-pin TQFN-EP package.
Benefits and Features
Low Power Consumption
●● Enables < 0.8W Total SFP+ Module Power
Dissipation
●● 380mW Typical IC Power Dissipation at 3.3V
(I_{LD_MOD} = 45mA, I_BIAS = 45mA)
Flexibility
●● Multirate up to 11.3Gbps (NRZ) Operation with Rate
Select for 1.25Gbps to 4.25Gbps Operation
●● Programmable Laser-Diode Modulation Current from
10mA to 85mA
●● Programmable Tx Input Equalization and Rx Output
Deemphasis
Safety and Monitoring
●● Integrated Eye Safety Features with Maskable Fault
and Interrupt Signal Generation
●● Analog Monitors with Integrated 12-Bit ADC, Fully
Supporting SFF-8472 DDM
Accurate Analog Measurements
●● High-Accuracy Temperature, VCC, and RSSI
Sensors
●● Enables Use of Simple Digital-Only µC
Simplified Block Diagram
Applications
●
10GBASE-LR SFP+ Optical Transceivers
Ordering Information appears at end of data sheet.
50Ω
RIN+
1.25Gbps TO 11.3Gbps, DUAL-PATH LIMITING AMPLIFIER
50Ω
LPF
4G
50Ω
RIN-
MUX
LOS
RX-LOS
10G
CSEL
SDA
SCL
VCCTO
TOUTA
TOUTC
VOUT
2-WIRE/3-WIRE
DDM
VCC
TEMP
BADC TX-POWER RSSI
1.25Gbps to 11.3Gbps, DC-COUPLED LASER DRIVER
APC
50Ω
TX-LOS
DC-COUPLED
LASER DRIVER
EQUALIZER
50Ω
ROUT+
ROUT-
RSSI
50Ω
TIN+
TIN-
19-6787; Rev 3; 9/14