MAX3798:1.0625Gbps to 10.32Gbps, Integrated, Low-Power SFP+ Limiting Amplifier and VCSEL Driver

Industry's First Combination VCSEL Driver and Limiting Amp for 10G SFP+ Ethernet and Fibre Channel

The MAX3798 is a highly integrated limiting amplifier and VCSEL driver designed for 1x/2x/4x/8x Fibre Channel transmission systems at data rates up to 8.5Gbps as well as for 10GBASE-SR transmission systems at a data rate of 10.3125Gbps. 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 back-terminated for a 50Ω transmission line PCB design. The use of a 3-wire digital interface reduces the pin count while enabling advanced Rx (mode selection, LOS threshold, LOS squelch, LOS polarity, CML output level, signal path polarity, slew-rate control, deemphasis, and fast mode-select change time) and Tx settings (modulation current, bias current, polarity, programmable deemphasis, eye-crossing adjustment, and eye safety control) without the need for external components. The MAX3798 provides multiple current and voltage DACs to allow the use of low-cost controller ICs. The MAX3798 is packaged in a lead-free, 5mm x 5mm, 32-pin TQFN package.

Key Features
  • Low Power Dissipation of 320mW at 3.3V Power Supply
  • Up to 10.32Gbps (NRZ) Operation
  • 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
  • Mode Select for High-Gain Mode and High-Bandwidth Mode
  • CML Output Slew-Rate Adjustment for High-Gain Mode
  • CML Output with Continuous Level Adjustment
  • CML Output Squelch
  • Polarity Select for Rx and Tx
  • LOS Assert Level Adjustment
  • LOS Polarity Select
  • Modulation Current Up to 12mA Into 100Ω Differential Load
  • Bias Current Up to 15mA
  • Integrated Eye Safety Features
  • Selectable Deemphasis at Rx Output
  • 3-Wire Digital Interface
  • Eye-Crossing Adjustment of Modulation Output
  • Programmable Deemphasis at Tx Output
  • Fast Mode-Select Change Time of 10µs
MAX3798: Typical Application Circuit
MAX3798: Typical Application Circuit
Applications/Uses
  • 10GBASE-LR SFP+ Optical Transceiver (1310nm VCSEL)
  • 10GBASE-LRM SFP+ Optical Transceiver (1310nm VCSEL)
  • 10GBASE-SR SFP+ Optical Transceiver
  • 1x/2x/4x/8x SFF/SFP/SFP+ MSA Fibre Channel (FC) Optical Transceiver
DataSheet
titleDownload file
MAX3798 Data SheetMAX3798.pdf
Parametrics
Part NumberTarget Oper. Range
(Gbps)
Data Rate
(Mbps)
Data Rate
(Mbps)
VSUPPLY
(V)
ICC
(mA)
I/O TypeIMOD
(mA)
IBIAS
(mA)
Package/PinsBudgetary
Price
minmaxtypmaxmaxSee Notes
MAX37981 to 4.5
5 to >10
1000103203.397CML1215TQFN/32$3.35 @1k
Design kits & evaluation modules
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX3798ETJ+ActiveTQFN,;32 pin;26 mm²-40°C to +85°CLead Free
MAX3798ETJ+TActiveTQFN,;32 pin;26 mm²-40°C to +85°CLead Free
MAX3798.pdf MAX3798
MAX3798_cn.pdf MAX3798
MAX3798.pdf MAX3798
MAX3798.pdf MAX3798
MAX3798.pdf MAX3798
MAX3798_cn.pdf MAX3798