MAX3798 Datasheet, PDF (1/35 Pages) Maxim Integrated Products – 1.0625Gbps to 10.32Gbps, Integrated, Low-Power SFP+ Limiting Amplifier and VCSEL Driver

19-4360; Rev 0; 10/08
1.0625Gbps to 10.32Gbps, Integrated, Low-
Power SFP+ Limiting Amplifier and VCSEL Driver
General Description
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 sys-
tems 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 ampli-
fier 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, deempha-
sis, and fast mode-select change time) and Tx settings
(modulation current, bias current, polarity, programma-
ble deemphasis, eye-crossing adjustment, and eye
safety control) without the need for external compo-
nents. The MAX3798 provides multiple current and volt-
age 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.
Applications
10GBASE-SR SFP+ Optical Transceiver
1x/2x/4x/8x SFF/SFP/SFP+ MSA Fibre Channel
(FC) Optical Transceiver
10GBASE-LR SFP+ Optical Transceiver (1310nm
VCSEL)
10GBASE-LRM SFP+ Optical Transceiver
(1310nm VCSEL)
Features
♦ Low Power Dissipation of 320mW at 3.3V Power
Supply
♦ Up to 10.32Gbps (NRZ) Operation
♦ 3mV_P-P Receiver Sensitivity at 10.32Gbps
♦ 4ps_P-P DJ at Receiver Output at 8.5Gbps 8B/10B
♦ 4ps_P-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
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX3798ETJ+
-40°C to +85°C
32 TQFN-EP*
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.