MAX3946 19-5182 Rev 1 5/11 1Gbps to 11.3Gbps, SFP+ Laser Driver with Laser Impedance Mismatch Tolerance General Description Features The MAX3946 is a +3.3V, multirate, low-power laser S 225mW Power Dissipation Enables < 1W SFP+ diode driver designed for Ethernet and Fibre Channel Modules transmission systems at data rates up to 11.3Gbps. S Up to 100mW Power Consumption Reduction by This device is optimized to drive a differential transmit- Enabling the Use of Unmatched FP/DFB TOSAs ter optical subassembly (TOSA) with a 25I flex circuit. S Supports SFF-8431 SFP+ MSA and SFF-8472 The unique design of the output stage enables use of Digital Diagnostic unmatched TOSAs, greatly reducing headroom limita- tions and lowering power consumption. S 225mW Power Dissipation at 3.3V (I = 40mA, MOD I = 60mA Assuming 25I TOSA) BIAS The device receives differential CML-compatible signals S Single +3.3V Power Supply with on-chip line termination. It can deliver laser modula- tion current of up to 80mA, at an edge speed of 22ps S Up to 11.3Gbps (NRZ) Operation (20% to 80%), into a 5I to 25I external differential load. S Programmable Modulation Current from 10mA to The device is designed to have a symmetrical output 100mA (5I Load) stage with on-chip back terminations integrated into S Programmable Bias Current from 5mA to 80mA its outputs. A high-bandwidth, fully differential signal path is implemented to minimize deterministic jitter. An S Programmable Input Equalization equalization block can be activated to compensate for S Programmable Output Deemphasis the SFP+ connector. The integrated bias circuit provides S 25I Output Back Termination at TOUT+ and programmable laser bias current up to 80mA. Both the TOUT- laser bias generator and the laser modulator can be dis- abled from a single pin. S DJ Performance 7ps with Mismatched P-P Differential Load (5I) A 3-wire digital interface reduces the pin count and permits adjustment of input equalization, pulse-width S DJ Performance 5ps with Mismatched P-P adjustment, Tx polarity, Tx deemphasis, modulation cur- Differential Load (25I) rent, and bias current without the need for external com- S DJ Performance 5ps with 50I Differential Load P-P ponents. The MAX3946 is available in a 4mm x 4mm, S Programmable Pulse Width 24-pin TQFN package. S Edge Transition Times of 22ps Applications S Bias Current Monitor 4x/8x FC SFP+ Optical Transceivers S Integrated Eye Safety Features 10GFC SFP+ Optical Transceivers S 3-Wire Digital Interface 10GBASE-LR SFP+ Optical Transceivers S -40C to +95C Operation 10GBASE-LRM SFP+ Optical Transceivers Ordering Information OC192-SR XFP/SFP+ SDH/SONET Transceivers PART TEMP RANGE PIN-PACKAGE MAX3946ETG+ -40C to +85C 24 TQFN-EP* Note: Parts are guaranteed by design and characterization to operate over the -40C to +95C ambient temperature range (T ) and are tested up to +85C. A +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE1Gbps to 11.3Gbps, SFP+ Laser Driver with Laser Impedance Mismatch Tolerance ABSOLUTE MAXIMUM RATINGS V , V , V ................................................-0.3V to +4.0V Current into BIAS .........................................................................+130mA CC CCT CCD Current Into TOUT+ and TOUT- .................................... +100mA Continuous Power Dissipation (T = +70NC) A Current Into TIN+ and TIN- ............................. -20mA to +20mA TQFN (derate 27.8mW/NC above +70NC)..................2222mW Voltage Range at TIN+, TIN-, Storage Temperature Range .......................... -55NC to +150NC DISABLE, SDA, SCL, CSEL, FAULT, Die Attach Temperature .................................................+400NC BMAX, and BMON ................................ -0.3V to (V + 0.3V) Lead Temperature (soldering, 10s) ................................+300NC CC Voltage Range at BIAS ........................................................-0.3V to V Soldering Temperature (reflow) ......................................+260NC CC Voltage Range at TOUT+ and TOUT- ....(V - 1.3V) to (V + 1.3V) CC CC Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. PACKAGE THERMAL CHARACTERISTICS (Note 1) TQFN Junction-to-Ambient Thermal Resistance (q ) ..........36C/W JA Junction-to-Case Thermal Resistance (q ) .................3C/W JC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four- layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (V = +2.85V to +3.63V, T = -40C to +85C, and Figure 1. Guaranteed by design and characterization from T = -40C to +95C. CC A A Typical values are at V = +3.3V, I = 60mA, I = 40mA, 25I differential output load, and T = +25C, unless otherwise CC BIAS MOD A noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS POWER SUPPLY Excludes output current through the exter- Power-Supply Current I 68 90 mA CC nal pullup inductors (Note 3) Power-Supply Voltage V 2.85 3.63 V CC DC to 10MHz 100 Power-Supply Noise mV P-P 10MHz to 20MHz 10 POWER-ON RESET V for Enable High 2.55 2.75 V CC V for Enable Low 2.3 2.45 V CC DATA INPUT SPECIFICATION Input Data Rate 1 10 11.3 Gbps TXEQ EN = high, launch amplitude into 0.19 0.7 FR4 transmission line P 5.5in Differential Input Voltage V V IN P-P TXEQ EN = low 0.15 1.0 Differential Input Resistance R 75 100 125 I IN Differential Input Return Loss SDD11 Part powered on, f P 10GHz 12 dB Common-Mode Input Return SCC11 Part powered on, 1GHz P f P 10GHz 10 dB Loss BIAS GENERATOR Current into BIAS pin, DISABLE = low, and Maximum Bias Current I 80 mA BIASMAX TX EN = high 2 MAX3946