LTC5100 3.3V, 3.2Gbps VCSEL Driver FEATURES DESCRIPTIO n 155Mbps to 3.2Gbps Laser Diode Driver for VCSELs* The LTC 5100 is a 3.2Gbps VCSEL driver offering an n 60ps Rise and Fall Times, 10ps Deterministic Jitter unprecedented level of integration and high speed perfor- n Eye Diagram is Stable and Consistent Across mance. The part incorporates a full range of features to Modulation Range and Temperature ensure consistently outstanding eye diagrams. The data n 1mA to 12mA Modulation Current inputs are AC coupled, eliminating the need for external n Easy Board Layout, Laser can be Remotely Located capacitors. The LTC5100 has a precisely controlled 50W if Desired output that is DC coupled to the laser, allowing arbitrary n No Input Matching or AC Coupling Components placement of the IC. No coupling capacitors, ferrite beads Needed or external transistors are needed, simplifying layout, n On-Chip ADC for Monitoring Critical Parameters reducing board area and the risk of signal corruption. The TM 2 n Digital Setup and Control with I C Serial Interface unique output stage of the LTC5100 confines the modula- n Emulation and Set-Up Software Available** tion current to the ground system, isolating the high speed n Operates Standalone or with a Microprocessor signal from the power supply to minimize RFI. n On-Chip DACs Eliminate External Potentiometers The LTC5100 supports fully automated production with its n Constant Current or Automatic Power Control extensive monitoring and control features. Integrated 10-bit n First and Second Order Temperature Compensation DACs eliminate the need for external potentiometers. An on- n On-Chip Temperature Sensor board 10-bit ADC provides the laser current and voltage, n Extensive Eye Safety Features as well as monitor diode current and temperature. Status n Single 3.3V Supply 2 information is available from the I C serial interface for feed- n 4mm 4mm QFN Package back and statistical process control. U APPLICATIO S An internal digital controller compensates laser tempera- ture drift and provides extensive laser safety features. n Gigabit Ethernet and Fibre Channel Transceivers n SFF and SFP Transceiver Modules , LTC and LT are registered trademarks of Linear Technology Corporation. n Proprietary Fiber Optic Links 2 I C is a trademark of Philips Electronics N.V. *Vertical Cavity Surface Emitting Laser **Downloadable from www.linear.com TYPICAL APPLICATIO 3.3V 24LC00 EEPROM IN SOT-23 PACKAGE V DD SDA MD ADC SCL 3.2Gbps Electrical Eye Diagram DIGITAL DAC 10nF CONTROLLER SRC EN FAULT DAC 50 1mA/DIV MODA ARBITRARY + IN DISTANCE + MODB 100 SERIALIZER IN 3.2Gbps MODULATOR 50ps/DIV 5100 TA01 V SS 5100 F01 WARNING: POTENTIAL EYE HAZARD. SEE EYE SAFETY INFORMATION Figure 1. VCSEL Transmitter with Automatic Power Control sn5100 5100fs 1 U ULTC5100 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) V , V ............................................................. 4V DD DD(HS) ORDER PART TOP VIEW + IN , IN (Cml en = 1) (Note 6) NUMBER Peak Voltage........... V 1.2V to V + 0.3V DD(HS) DD(HS) 16 15 14 13 LTC5100EUF Average Voltage...... V 0.6V to V + 0.3V DD(HS) DD(HS) V 1 12 V SS SS + IN , IN (Cml en = 0) (Note 4).. 0.3V to V + 0.3V + DD(HS) IN 2 11 MODA 17 Cml en = 0 (Note 4) IN MODB 3 10 + Peak Difference Between IN and IN .............. 2.5V V 4 9 V SS SS + 5 6 7 8 Average Difference Between IN and IN ....... 1.25V UF PART MARKING MODA, MODB (Transmitter Disabled) .... 0.3V to 2.75V MODA, MODB 5100 UF PACKAGE (Transmitter Enabled) ............ V 2.75V to 2.75V 16-LEAD (4mm 4mm) PLASTIC QFN DD(HS) T = 125 C, q = 37 C/W JMAX JA EN, SDA, SCL, FAULT .....................0.3V to V + 0.3V DD EXPOSED PAD IS V (PIN 17) SS MD, SRC ................................................... 0.3V to V MUST BE SOLDERED TO PCB GROUND PLANE DD Ambient Operating Temperature Range .. 40 C to 85 C Consult LTC Marketing for parts specified with wider operating temperature ranges. Storage Temperature Range ................ 65 C to 125 C ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C V = V = 3.3V, I = 24mA I = 12mA (I = 24mA) 49.9W , 1% A DD DD(HS) S M MPP resistor from SRC (Pin 14) to MODA (Pin 11) 50W , 1% load AC coupled to MODB (Pin 10) 10nF, 10% capacitor from SRC (Pin 14) to V Cml en = 0, Lpc en = 1, transmitter enabled, unless otherwise noted. Test circuit in Figure 5. SS PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply V , V Operating Voltage l 3.135 3.3 3.465 V DD DD(HS) V + V Quiescent Current, V = 3.465V DD DD(HS) DD Excluding the SRC Pin Current (Note 2) Transmitter Disabled, Power down en = 1 4.5 mA Transmitter Enabled, Is rng = Im rng = 3 54 mA Impp = 24mA + High Speed Data Inputs (IN and IN Pins) (Test Circuit, Figure 5) Input Signal Amplitude Peak-to-Peak Differential Voltage (The Single- 500 to 2400 mV P-P Ended Peak-to-Peak Voltage is One Half the Differential Voltage) Common Mode Input Signal Range (Note 3) Cml en = 0 (Note 4) 0 V V DD(HS) Differential Input Resistance 80 to 120 W Common Mode Input Resistance Cml en = 0 (Note 5) 50 kW Open-Circuit Voltage Cml en = 0 (Note 5) 1.65 V SRC Pin Current, I S Full-Scale I Current Is rng = 0 6 9 mA S Is rng = 1 12 18 mA Is rng = 2 18 27 mA Is rng = 3 24 36 mA Minimum Operating Current (Note 7) 1/16 of Full-Scale I Current S Resolution 10 Bits SRC Pin Voltage Range 1.2 V V DD 200mV sn5100 5100fs 2 FAULT V DD SDA EN SCL SRC V MD DD(HS) U WWW