11.3Gbps Transceiver with Digital Monitors and DC-Coupled Laser Driver

Lowest Power and Highest Integration Solution for SFP+ Optical Module


The MAX3956 is an 11.3Gbps, highly-integrated, low-power transceiver with digital diagnostics monitoring (DDM) designed for next-generation Ethernet transmission systems. The receiver incorporates a limiting amplifier and loss-of-signal (LOS) circuit. The limiting amplifier features dual-path architecture optimizing the performance for signals up to 4.25Gbps and up to 11.3Gbps, respectively. The transmitter incorporates Maxim’s proprietary 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, VCC, and received signal strength indication (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.

MAX3956: Simplified Block Diagram MAX3956: Simplified Block Diagram Enlarge+

Key Features

  • Low Power Consumption
    • Enables < 0.8W Total SFP+ Module Power Dissipation
    • 380mW Typical IC Power Dissipation at 3.3V (ILD_MOD = 45mA, IBIAS = 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


  • 10GBASE-LR SFP+ Optical Transceivers
Part Number Applications Target Oper. Range
Data Rate
Data Rate
Oper. Temp.
min max typ max max
10G Ethernet
1.25 to 11.3 1250 11300 3.3 105 CML 85 100 -40 to +95
See All Optical Transceivers (15)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Technical Documents

App Note 5888 Recommended Initialization Sequence for the MAX3955 and MAX3956 Devices

Quality and Environmental Data

Product Reliability Reports: MAX3956.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Related Resources