Maxim MAX3799 14Gbps VCSEL激光驱动方案

Maxim公司的MAX3799 是高度集成的限幅放大器和VCSEL驱动器,工作频率高达14Gbps,非常适合以太网和光纤通路应用. 采用MAX3799能使单模设计和1000BASE-SR 与10GBASE-SR指标兼容,采用10.32Gbps ROSA (-19.7dBm OMA)在1.25Gbps可得到-21.5dBm的光灵敏度,3.3V电源的功耗仅为320mW,Rx/Tx的电性能为14.025Gbps,Rx/Tx输出的上升和下降时间为26ps.速率有1Gbps或10Gbps模式.本文介绍了MAX3799主要特性,方框图,VCSEL驱动器测试电路,眼安全电路和典型应用电路,以及MAX3799评估板主要特性,电路图和所用元件列表.

The MAX3799 is a highly integrated limiting amplifier and VCSEL driver that operates up to 14Gbps, making it suitable for Ethernet and Fibre Channel applications.

By providing a selectable data path with a noise-shaping filter, the MAX3799 enables a module with 10G optics to be fully compliant with both 1000BASE-SR and 10GBASE-SR specifications. Operating from a single +3.3V supply, this low-power integrated limiting amplifier and VCSEL driver IC enables a platform design for SFP MSA as well as for SFP+ MSA-based optical transceivers. The high-sensitivity limiting amplifier limits the differential input signal generated by a transimpedance amplifier into a CML-level differential output signal. The compact VCSEL driver provides a modulation and a bias current for a VCSEL diode. The optical average power is controlled by an average power control (APC) loop implemented by a controller that interfaces to the VCSEL driver through a 3-wire digital interface. All differential I/Os are optimally backterminated for a 50 ohm transmission line PCB design.

The use of a 3-wire digital interface reduces the pin count while enabling advanced Rx (rate selection, LOS threshold, LOS squelch, LOS polarity, CML output level, signal path polarity, deemphasis, and fast mode-select change time) and Tx settings (modulation current, bias urrent, polarity, and eye safety control) without the need for external components. The MAX3799 provides multiple current and voltage DACs to allow the use of low-cost controller ICs.

The MAX3799 is packaged in a lead-free, 5mm x 5mm, 32-pin TQFN package.

MAX3799主要特性:

♦ Enables Single-Module Design Compliance with 1000BASE-SR and 10GBASE-SR Specifications

♦ -21.5dBm Optical Sensitivity at 1.25Gbps Using a 10.32Gbps ROSA (-19.7dBm OMA)

♦ Low Power Dissipation of 320mW at 3.3V Power Supply

♦ Typical Electrical Performance of 14.025Gbps on Rx/Tx (Non-Retimed 16x Fibre Channel Solution)

♦ 3mVP-P Receiver Sensitivity at 10.32Gbps

♦ 4psP-P DJ at Receiver Output at 8.5Gbps 8B/10B

♦ 4psP-P DJ at Receiver Output at 10.32Gbps 231 - 1 PRBS

♦ 26ps Rise and Fall Time at Rx/Tx Output

♦ Rate Select for 1Gbps Mode or 10Gbps Mode

♦ CML Output Squelch

♦ Polarity Select for Rx and Tx

♦ LOS Assert Level Adjustment

♦ LOS Polarity Select

♦ Modulation Current Up to 12mA Into 100ohm Differential Load

♦ Bias Current Up to 15mA

♦ Integrated Eye Safety Features

♦ 3-Wire Digital Interface

♦ Programmable Deemphasis at Tx Output

MAX3799应用:

1000BASE-SR/10GBASE-SR Multirate SFP+Optical Transceiver

1x/2x/4x/8x/16x SFF/SFP/SFP+ MSA Fibre Channel (FC) Optical Transceiver

图1.MAX3799功能方框图

图2. VCSEL 驱动器测试电路

图3. 眼安全电路

图4. MAX3799典型应用电路

MAX3799 评估板套件

The MAX3799 evaluation kit (EV kit) is an assembled electrical demonstration board that provides easy com­puter-controlled evaluation of the MAX3799 multirate lim­iting amplifier and VCSEL driver. The included software communicates with the EV kit through the USB port, and provides access to all the internal registers to optimize the functionality of the MAX3799. The EV kit is powered by a +3.3V supply and USB port. SMA connectors are used for the high-speed inputs and outputs. An LED indicates the status of USB power.

MAX3799 评估板主要特性:

Fully Assembled and Tested

Software Control Through USB Port

SMA Connectors for High-Speed Inputs and Outputs

Powered by +3.3V Supply and USB Port

Indicator for USB Power

图5.MAX3799 评估板电路图(1)

图6.MAX3799 评估板电路图(2)
元件列表: