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

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. Applications

* 10GBASE-LR SFP+ Optical Transceivers

* Low Power Consumption

* Enables < 0.8W Total SFP+ Module Power Dissipation

* 380mW Typical IC Power Dissipation at 3.3V (ILDMOD = 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