MAX3946 1.0625Gbps至11.3Gbps、SF

MAX3946 1.0625Gbps至11.3Gbps、SFP+激光器驱动器，容许激光器阻抗失配

概述

The MAX3946 is a +3.3V, multirate, low-power laser diode driver designed for Ethernet and Fibre Channel transmission systems at data rates up to 11.3Gbps. This device is optimized to drive a differential transmiter optical subassembly (TOSA) with a 25Ω flex circuit. The unique design of the output stage enables use of unmatched TOSAs, greatly reducing headroom limitations and lowering power consumption.

The device receives differential CML-compatible signals with on-chip line termination. It can deliver laser modulation current of up to 80mA, at an edge speed of 20ps (20% to 80%), into a 5Ω to 25Ω external differential load. The device is designed to have a symmetrical output stage with on-chip back terminations integrated into its outputs. A high-bandwidth, fully differential signal path is implemented to minimize deterministic jitter. An equalization block can be activated to compensate for the SFP+ connector. The integrated bias circuit provides programmable laser bias current up to 80mA. Both the laser bias generator and the laser modulator can be disabled from a single pin, DISABLE.

A 3-wire digital interface reduces the pin count and permits adjustment of input equalization, pulse-width adjustment, Tx polarity, Tx deemphasis, modulation current, and bias current without the need for external components. The MAX3946 is available in a 4mm x 4mm, 24-pin TQFN package.

关键特性

225mW Power Dissipation Enables < 1W SFP+ Modules

Up to 100mW Power Consumption Reduction by Enabling the Use of Unmatched FP/DFB TOSAs

Supports SFF-8431 SFP+ MSA and SFF-8472 Digital Diagnostic

225mW Power Dissipation at 3.3V (I_MOD = 40mA, I_BIAS = 60mA Assuming 25Ω TOSA)

Single +3.3V Power Supply

Up to 11.3Gbps (NRZ) Operation

Programmable Modulation Current from 10mA to 100mA (5Ω Load)

Programmable Bias Current from 5mA to 80mA

Programmable Input Equalization

Programmable Output Deemphasis

25Ω Output Back Termination at TOUT+ and TOUT-

DJ Performance 7ps_P-P with Mismatched Differential Load (5Ω)

DJ Performance 5ps_P-P with Mismatched Differential Load (25Ω)

DJ Performance 5ps_P-P with 50Ω Differential Load

Programmable Pulse Width

Edge Transition Times of 20ps

Bias Current Monitor

Integrated Eye Safety Features

3-Wire Digital Interface

-40°C to +95°C Operation

应用/使用

10GBASE-LR SFP+光收发器
10GBASE-LRM SFP+光收发器
10GFC SFP+光收发器
4x/8x FC SFP+光收发器
OC192-SR XFP/SFP+光收发器

功能框图