M02094 3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps The M02094 is a highly integrated, programmable VCSEL driver intended for SFP/SFF modules to 2.0 Gbps. Using differential PECL data inputs, the M02094 supplies the bias and modulation current required to drive a VCSEL or edge-emitting laser. The modulation output can be AC or DC-coupled to a FP laser diode or AC coupled to a common anode or common cathode VCSEL. Peaking adjustment is available to improve VCSEL fall time. EPON burst mode operation is supported with no extra components. Integrated safety circuitry detects faults and provides latched bias and modulation current shutdown. Applications Features * * * * * High speed operation; suitable for SFP/SFF applications from 155Mbps to 2.0 Gbps. Typical rise/fall times < 110 ps. * Supports Common Anode VCSEL, Common Cathode VCSEL, or FP LASER. May be used with or without a monitor photodiode. * Programmable temperature compensation. Modulation output and bias output can be controlled using a few discrete resistors. * Supports DDMI (SFF-8472) diagnostics. * DC or AC coupled modulation drive. * Peaking circuit to optimize VCSEL response. * Low overshoot allows high extinction ratio with low jitter. * Supports E-PON burst mode with no extra components * Automatic Laser Power Control, with "Slow-Start". * 3.3V or 5V operation EPON FTTH modules Gigabit Ethernet modules 1G/2G Fibre Channel modules Digital Video Internal 3.3V reg. PEAKAD J GND C C3 V VC C Functional Block Diagram SV Internal Power Bus CC and IBOUT_CC OUT- DIN + Input Buffer D IN- Output Buffer Laser Driver OUT+ GND0 VCC3 -1.3V IB OUT_CA and SGND IPIN Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential APC CCSEL C DISDLY TxPwr MON BIASMON SET APC SET Automatic Power Control (laser bias current) MOD MON MOD TCSLOPE Modulation Control VCC3SEL FAIL DIS 02094-DSH-001-C RESET Safety Circuitry with Latched Fault TX Disable March 2005 M02094 Data Sheet Ordering Information Part Number Package Operating Temperature M02094-11 * QFN24 M02094-EVM Combination Electrical and Optical Evaluation board * The letter "G" designator after the part number indicates that the device is RoHS-compliant. Refer to www.mindspeed.com for additionalinformation. Revision History Revision Level Date ASIC Revision A Advance October 2003 x Advance. B Preliminary March 2004 x Preliminary release. C Released March 2005 x Released. New datasheet format. Changes to Absolute Maximum Ratings, Operating Temperature, AC and DC specifications. New section on video operation. Description 24 VCC CCSEL CAPC VCC3 PEAKADJ TCSLOPE MODSET Pin Configuration Typical Electrical Eye Diagram, Common Anode Mode 19 1 18 SVCC/ IBOUTCC OUT- DIN+ OUT+ DIN\ VCC3SEL GND0 GND, connect to PCB ground IBOUTCA/ SGND DIS FAIL 6 13 ii Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential IPIN TXPWRMON BIASMON MODMON 12 DISDLY RESET 7 APCSET Typical Electrical Eye Diagram, Common Cathode Mode with Peaking 4 X 4 mm 02094-DSH-001-C 1.0 Product Specification 1.1 Absolute Maximum Ratings These are the absolute maximum ratings at or beyond which the IC can be expected to fail or be damaged. Reliable operation at these extremes for any length of time is not implied. Table 1-1. Absolute Maximum Ratings Symbol Parameter Rating Units VCC Power supply voltage -0.4 to +6.0 V VCC3 3.3V power supply voltage -0.4 to +4.0 V TSTG Storage temperature -65 to +150 C IBIASOUTCA (MAX) Maximum bias output current for common anode laser 75 mA IBIASOUTCC (MAX) Maximum bias output current for common cathode laser 30 mA IMODCA (MAX) Maximum modulation current for common anode laser 70 mA IMODCC (MAX) Maximum modulation current for common cathode laser 30 mA DIN+/- Data inputs -0.4 to VCC3 + 0.4 V DIS Disable input -0.4 to VCC + 0.4 V BIASMON, MODMON Bias and modulation output current mirror compliance voltage -0.4 to VCC3 + 0.4 V IPIN Photodiode anode voltage -0.4 to VCC3 + 0.4 V IPIN Sink or Source Current 2.0 mA FAIL Status flag -0.4 to VCC + 0.4 V APCSET, MODSET Set inputs -0.4 to VCC3 + 0.4 V TCSLOPE Temperature compensation slope -0.4 to VCC3 + 0.4 V OUT+, OUT- Output -0.4 to VCC3 + 0.4 V 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 3 M02094 Data Sheet 1.2 Table 1-2. Recommended Operating Conditions Recommended Operating Conditions Parameter Power supply (VCC-GND) Rating Units 3.3 7.5% or 5.0 + 10%,-5% V -40 to + 95 C Operating ambient 1.3 DC Characteristics (VCC = +3.05V to +3.55V or 4.75V to 5.5V, TA = -40 C to +95 C, unless otherwise noted) Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 C, unless otherwise noted. Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 C, unless otherwise noted Table 1-3. Symbol ICC DC Characteristics Parameter Supply current excluding IMOD and IBIAS Conditions Min. Typ. Max. PEAKADJ high (no peaking adjust) - Common anode operation(1) - 28 48 Common cathode operation(1) - 35 55 - 2 15 Additional current when PEAKADJ is used. Units mA Additional current when operating from a 5V supply(2) IBOUTCA Bias current adjust range, common anode mode V(IBIASOUT) > 0.7V 1 50 mA IBOUTCC Bias current adjust range, common cathode mode V(IBIASOUT) < 2.5V 0.5 15 mA IBOFF Bias current with optical output disabled DIS = high V(IBOUTCA) = VCC3 for common anode operation. V(IBOUTCC) = 0V for common cathode operation. - - 150 A Ratio of IBIAS current to BIASMON current CCSEL low, common anode mode CCSEL high, common cathode mode - 45.7 13.5 - A/A 1.5 - - V 10 - 1500 A VMD Monitor diode reverse bias voltage IMD Monitor diode current adjustment range Adjusted with RAPCSET Ratio of TxPwrMON current to monitor photodiode current 4 1 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential A/A 02094-DSH-001-C Product Specification Table 1-3. DC Characteristics Symbol CMD_MAX Parameter Conditions Min. Typ. Maximum monitor photodiode capacitance for APC loop stability. Includes all associated parasitic capacitances. TTL/CMOS input high voltage (DIS) TTL/CMOS input low voltage (DIS) Max. Units 100 pF 2.0 - 5.5 V - - 0.8 V CMOS input high voltage (VCC3SEL) 2.4 V CMOS input low voltage (VCC3SEL) 1.2 V Logic output high voltage (FAIL) With external 10k pull-up to VCC. VCC - 0.6 - - V Logic output low voltage (FAIL) For 6.8k to 10k ohm resistor when pulled up to 5V For 4.7k to 10k ohm resistor when pulled up to 3.3V - - 0.4 V RIN Differential input impedance Data inputs -- 6800 - VSELF Self-biased common-mode input voltage -- VCC3 - 1.3 -- V VINCM Common-mode input compliance voltage Data inputs VCC3-1.45 - VCC3-[VIN(Diff)]/4 V Differential input voltage = 2 x (DIN+HIGH - DIN+LOW) 200 - 2400 mVpp 3.3V supply detection, lower threshold 2.5 2.8 2.95 V VCC3THH(3) 3.3V supply detection, upper threshold 3.65 3.8 4.1 V VIN(DIFF) VCC3THL(3) VCC5THL 5V supply detection, lower threshold 3.9 4.25 4.65 V VCC5THH 5V supply detection, upper threshold 5.45 5.8 6.2 V Reference voltage for MODSET 1.18 1.3 1.4 V VREF1 VAPCSET VBL Reference voltage for APCSET 1.35 Bias_OK lower voltage threshold 02094-DSH-001-C 0.88 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 1.0 V 1.05 V 5 M02094 Data Sheet Table 1-3. Symbol VBH DC Characteristics Parameter Conditions Bias_OK upper voltage threshold Lower voltage threshold for fault inputs IBOUTCA, OUT+, CAPC, and MODSET FAIL asserts if any of these signals fall below this value. VFAULTH(5) Upper voltage threshold for FAIL asserts if any of these signals fall above this value. VFAULTL(4) fault inputs IBOUTCC VSELFL Self bias voltage for IBOUTCA During disable state and OUT+ VSELFH Self bias voltage for IBOUTCC During disable state Min. Typ. Max. Units 1.45 1.6 1.7 V 300 400 mV 2.6 2.9 VCC3 - 0.2 V 0.5 1.65 2.0 V 0 1.25 V Notes: 1. Excludes bias and modulation currents. 2. Bias and modulation currents add directly to power supply current in 5V applications. The additional supply current noted excludes these currents. 3. VCC3 "supply OK" circuitry monitors the internally regulated 3.3V supply when VCC = 5V (VCC3SEL =low). When VCC = 3.3V, VCC3 "supply OK" circuitry monitors VCC (VCC3SEL =high). 4. A low level at IBOUTCA does not trigger a fault condition during common cathode operation. 5. A low level at IBOUTCC does not trigger a fault condition during common anode operation. 1.4 AC Characteristics (VCC = 3.05 V to 3.55V or 4.7V to 5.5V, TA = -40 C to +95 C, unless otherwise noted) Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 C, unless otherwise noted. Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 C, unless otherwise noted. Table 1-4. Symbol IMOD IMOD(OFF)(2) AC Characteristics Parameter Conditions Min. Typ. Max. Units. Common Cathode Mode OUT+ and OUT- AC coupled into 50 load. 1 - 15 mA Common Anode Mode OUT+ and OUT- DC coupled into 25 load.(1) 3 Modulation current with output disabled DIS = high - - 150 A Ratio of modulation current to MODMON current CCSEL = high, RLOAD = 50 - 30 - A/A 104 ppm/C Modulation current adjust range 65 CCSEL = low 6 IMOD-TC Programmable range for modulation current temperature coefficient TTCSTART Temperature at which modulation current TC compensation enables Adjustable using TCSLOPE Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 45 0 - 20 C 02094-DSH-001-C Product Specification Table 1-4. Symbol AC Characteristics Parameter tr Modulation output rise time tf Modulation output fall time OSOFF Overshoot of modulation output current in the "off" direction RJ Random jitter DJ Deterministic jitter Conditions Min. Typ. Max. Units. (3) 20% to 80% into 25 . For IMOD from 3 mA to 30 mA. Measured using 11110000 pattern at 2.5 Gbps - 110 140 ps - 110 140 ps into 25 load -- 1 2 % - 1.2 - psrms Measured into 25 load, 231 - 1 PRBS at 2.0 Gbps 20 45 K28.5 pattern at 2.0 Gbps 20 45 pspp (includes pulse width distortion) Notes: 1. Minimum voltage at OUT+ > 0.7V. 2. The current through the laser in this state can be made negligible by adding a 1k or less resistor in parallel with the laser. 3. The M02094 is designed to drive 25 loads. External resistance should be added in series or parallel to the Laser to create this load impedance. In common cathode mode, 50 resistors internal to the M02094 are in parallel with the laser. 1.5 Safety Logic Timing (VCC = 3.05 V to 3.55V or 4.7V to 5.5V, TA = -40 C to +95 C, unless otherwise noted) Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 C, unless otherwise noted. Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 C, unless otherwise noted. Table 1-5. Symbol Safety Logic Timing Parameter Conditions Min. Typ. Max. Units. t_off DIS assert time Rising edge of DIS to fall of output signal below 10% of nominal(1) 10 s t_on DIS negate time Falling edge of DIS to rise of output signal above 90% of nominal(1) 1 ms 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 7 M02094 Data Sheet Table 1-5. Safety Logic Timing Symbol Parameter Conditions (2) Includes reset of FAIL; from power on after Supply_OK or from negation of DIS during reset of FAIL condition Min. Typ. Max. Units. 2 3 5 ms t_init Time to initialize t_fault Laser fault time - from fault condition From occurrence of fault condition or when to assertion of FAIL Supply_OK is beyond specified range 100 s t_reset DIS time to start reset DIS or ENA pulse width required to initialize safety circuitry or reset a latched fault 10(3) s t_onBM DIS negate (turn-on) time during burst-mode operation Using integrated switch at SVCC (3.3V operation) (4) 300 500 ns t_offBM DIS assert (turn-off) time during burst-mode operation Using integrated switch at SVCC (3.3V operation)(4) 200 500 ns Notes: 1. With CAPC = 2.2nF 2. User-adjustable. Specifications reflect timing with no external RESET capacitor. 3. With < 1nF capacitor from RESET pin to ground. 4. Imod > 12mA Figure 1-1. Safety Logic Timing Characteristics Slow Rise on Vcc=3.3V at Power-up (DIS Low) Hot Plug (DIS Low) 3.3V VCC3 and VCC5 status V CC3 and VCC5 "OK" VCC 3.3V VCC3 FAIL DIS (low) FAIL state at power-up will depend on pull-up voltage FAIL (low) DIS (low) (low) t_on < 1ms, (300 us typ.) LASER OUTPUT t_on < 1ms, (300 us typ.) LASER OUTPUT 8 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Product Specification Slow Rise on Vcc=5V at Power-up (DIS Low) 5V V CC 3.3V Transmitter Enable (DIS transition Low) VCC3 and VCC5 status (high) FAIL (low) DIS (low) VCC3 and VCC5 "OK" VCC3 (low) FAIL t_on < 1ms, (300 us typ.) (low) DIS t_on < 1ms, (300 us typ.) LASER OUTPUT LASER OUTPUT Transmitter Disable (DIS transition high) VCC3 and VCC5 status FAIL (high) VCC3 and VCC5 "OK" (low) DIS t_off < 10 us, (1 us typ.) 02094-DSH-001-C Fault recovery at: MODSET. C APC, OUT+, IBOUT CA or IBOUT CC Fault Removed FAIL remains high until reset by DIS going high FAIL DIS LASER OUTPUT Fault Recovery Behaviour LASER OUTPUT Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential t_reset, 10 us, min. t_on < 1ms 9 M02094 Data Sheet Response to Fault Fault at: MODSET. CAPC, OUTP, IBOUT CC or IBOUT CA FAIL Unsuccessful Fault Reset Attempt Fault Occurs t_fault < 100 us, (4 us typ.) t_init < 5ms, (3 ms typ.) FAIL DIS DIS LASER OUTPUT Figure 1-2. Fault Remains Fault at: APC SET t_reset, 10 us, min. LASER OUTPUT Relationship Between Data Inputs and Modulation Outputs D + IN 100 mV 1200 mV DIN- 200 mV 2400 mV V IN(DIFF) V OUT- VOUT+ > 0.7V GND 10 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C 2.0 Pin Description 2.1 Table 2-1. Pin Definitions Pin Definitions Pin Number Pin Name 1 VCC Pin equivalent load Function Power supply, 5V or 3.3V. VCC VCC3 Positive data input. Self biased. Compatible with AC coupled PECL, AC coupled CML, and DC-coupled PECL (when VCC = 3.3V). When DIN+ is high, OUT+ will sink current. VCC3-1.3V D +, D IN 2 DIN+ 3 DIN- 02094-DSH-001-C 4 k IN See DIN+ drawing Negative data input. Self biased Compatible with AC coupled PECL, AC coupled CML, and DC-coupled PECL (when VCC = 3.3V). Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 11 M02094 Data Sheet Table 2-1. Pin Number Pin Definitions Pin Name Pin equivalent load VCC 4 VCC3SEL VCC3 Function 3.3V VCC Select. Connect to VCC for VCC = 3.3V operation. Connect to GND for VCC = 5V operation. VCC3 SEL 190 72 k VCC VCC3 Bias and modulation output disable (TTL/CMOS). When high or left floating, the bias and modulation outputs are disabled. Set low for normal operation. 7 k DIS 5 DIS 80 k VCC Safety circuit fault output (TTL/CMOS). Goes high when a safety logic fault is detected. This output will also be high when DIS is high. Requires an external pull-up. FAIL 6 12 FAIL Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Pin Description Table 2-1. Pin Number Pin Definitions Pin Name Pin equivalent load VCC3 V CC 7 RESET Function Safety circuit reset. Leave open for normal operation or add a capacitor to ground to extend the reset time. Connect to GND to disable window comparators at APCSET RESET 190 Disable delay control. Connect to ground for normal operation. In burst mode operation add a capacitor from this pin to ground to set the maximum disable time. Disable times greater than this maximum will engage the "slow-start" circuitry. VCC 8 DISDLY DISDLY 190 V CC VCC3 Modulation Current Monitor. Connect to a resistor to GND. The current through this pin is typically 1/50th of the MODULATION current to the laser when CCSEL is low or 1/25th the MODULATION current when CCSEL is high. This pin may be left open if the feature is not needed and the M02094 current consumption will be reduced by 0.5mA typically. MOD MON 9 MODMON 190 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 13 M02094 Data Sheet Table 2-1. Pin Number 10 Pin Definitions Pin Name BIASMON Pin equivalent load See MODMON drawing VCC VCC3 Function Bias Current Monitor. Connect to a resistor to GND. The current through this pin is typically: 1/45.7th of the BIAS current to the laser when CCSEL is low 1/13.5th of the BIAS current to the laser when CCSEL is high This pin may be left open if the feature is not needed and the M02094 current consumption will be reduced by 0.5mA typically. Transmit Power Monitor. Connect to a resistor to GND. The current through this pin is approximately the same as the photodiode current into IPIN. The current out of this pin is low pass filtered (no external filtering required). This pin may be left open if the feature is not needed and the M02094 current consumption will be reduced by the IPIN current. TxPwr MON 11 TxPwrMON 33 V CC 12 APCSET VCC3 APCSET V CC VCC3 For CCSEL low - Current input from monitor photodiode anode. The APC loop will adjust the laser bias current to maintain a voltage at APCSET of approximately 1.3V and at this pin of approximately one VGS. For CCSEL high - Current source for monitor photodiode cathode. The APC loop will adjust the laser bias current to maintain a voltage at APCSET of approximately 1.3V and at this pin of approximately one VGS below VCC3. IPIN 13 Average Power Control, laser bias current adjustment. Connect to a resistor between this pin and ground to set the bias current to the laser. The APC loop will adjust the laser bias current to maintain a voltage at APCSET of approximately 1.3V. The current sourced from this pin is approximately the same as the current into IPIN. IPIN 33 14 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Pin Description Table 2-1. Pin Definitions Pin Number Pin Name Pin equivalent load V CC IBOUTCA (CCSEL = low) VCC 02094-DSH-001-C GNDO Switched ground connection for common cathode lasers (CCSEL must be high). Provides redundant shutdown during a disable or fault condition. This switch is disabled during common anode operation. SGND V 15 Laser bias current output for common anode lasers (CCSEL must be low). Connect directly to laser cathode or at higher bit rates through a ferrite or a resistor to isolate the capacitance of this pin from the modulation drive, (~ 6pF). Maintain a voltage at least 0.7V above GND at this pin IBOUTCA 14 SGND (CCSEL = high) Function CC Ground for output stage. May be connected directly to circuit board ground. At high bit rates (>2Gb/s) an optional inductor or ferrite may be added to reduce switching transients. GND0 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 15 M02094 Data Sheet Table 2-1. Pin Number Pin Definitions Pin Name Pin equivalent load Positive modulation current output (AC or DC coupled to cathode of laser in common anode designs). Sinks current when DIN+ is HIGH. Maintain a voltage > 0.7V at this pin. V CC 16 OUT+ Function OUT+ GND 0 17 OUT- See OUT+ drawing VCC SVCC (CCSEL = low) VCC3 Negative modulation current output (AC coupled to anode of laser in common cathode designs). Sinks current when DIN- is HIGH Maintain a voltage > 0.7V at this pin. Switched VCC. Supplies laser current for common anode designs. (CCSEL must be LOW). Provides redundant shutdown during a disable or fault condition. This switch is disabled during common cathode operation. SV CC 18 VCC IBOUTCC (CCSEL = high) IBOUT Laser bias current output for common cathode laser designs (CCSEL must be high). Connect directly to laser anode or at higher bit rates through a ferrite or a resistor to isolate the capacitance of this pin from the modulation drive. Maintain a voltage of < 2.5V at this pin. V CC3 CC 12 k 16 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Pin Description Table 2-1. Pin Number Pin Definitions Pin Name Pin equivalent load VCC 19 CCSEL V CC3 Function Laser select input. When high, common cathode operation is selected; IBOUTCC and SGND are functional and internal 50 output terminations are switched in at the modulation outputs OUT+ and OUT-. When low or floating, common anode operation is selected; IBOUTCA and SVCC are functional and the 50 internal termination resistors at OUT+ and OUT- are disconnected. CC SEL 24 k 48 k Automatic power control loop dominant pole capacitor. (Connect a capacitor between this pin and VCC3.) A nominal capacitance of 2.2nF will give a bias current enable time of less than 1 ms. VCC 20 CAPC C APC 100 VCC 21 02094-DSH-001-C VCC3 VCC 3.3V applications - Power supply input. Connect to VCC. 5V applications - Do not connect to 5V. Internally generated 3.3V power supply output. Do not attach to non-M02094 circuitry. VCC3 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 17 M02094 Data Sheet Table 2-1. Pin Number Pin Definitions Pin Name Pin equivalent load V CC 22 PEAKADJ 18 24 TCSLOPE CENTER PAD GND + - 1.28V 1.8 k CC MODSET Peaking adjustment input. A resistor (2k to 20k) between this pin and ground sets the amount of peaking current on OUT- to improve the fall time of the laser output. The peaking current is approximately (4 * (1.3V / resistance to ground)). Connect to VCC3 to disable peaking control. VCC3 PEAKADJ V 23 Function Modulation current control. Connect a resistor to ground to set the modulation current. VCC3 + - MODSET 1.28V 190 See MODSET drawing Modulation current temperature compensation slope adjustment. Connect a resistor to ground to set the temperature coefficient. Leave open to minimize the temperature compensation coefficient. Ground. Must be connected to ground for proper operation. This is the only package ground connection. Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Pin Description 24 VCC CCSEL CAPC VCC3 PEAKADJ MODSET Pin Assignments for M02094 Device TCSLOPE Figure 2-1. 19 1 18 SVCC/ IBOUTCC DIN+ OUT- DIN- OUT+ \ VCC3SEL GND0 GND, connect to PCB ground IBOUTCA/ SGND DIS 6 13 02094-DSH-001-C IPIN TXPWRMON BIASMON MODMON 12 DISDLY RESET 7 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential APCSET FAIL 4 X 4 mm 19 M02094 Data Sheet 20 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C 3.0 Functional Description 3.1 Overview The M02094 is a highly integrated laser driver intended for applications to 2.0 Gbps. Many features are user-adjustable, including common anode or common cathode laser mode, the APC (automatic power control) loop bias control (via a monitor photodiode), modulation current, temperature compensation control of modulation current, and peaking adjustment. The part may be operated from a 3.3V or 5V supply. For E-PON and other burst-mode applications, the part supports fast and accurate turn-on and turn-off of the laser bias and modulation currents. Safety circuitry is also included to provide a latched shut-down of laser bias and modulation current if a fault condition occurs. An internal VCC switch provides redundant shutdown when operating the device in common anode configuration. An internal ground switch provides redundant shutdown when operating the device in common cathode configuration. Modulation, bias, and transmit power monitor current mirrors are provided for DDMI applications and allow monitoring without disturbing the analog signal path. 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 21 M02094 Data Sheet Internal 3.3V reg. PEAKAD J V GND C C3 M02094 Block Diagram Example VC C Figure 3-1. SVCC and Internal Power Bus IBO UT_CC OUT- DIN + Input Buffer D IN - Output Buffer Laser Driver OUT+ GND0 VCC3 -1.3V IB O UT_CA and SGND IPIN Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential APC CCSEL C DISDLY TxPwr MON BIASMON APC SET Automatic Power Control (laser bias current) MOD MON SET MOD TCSLOPE Modulation Control VCC3SEL FAIL DIS 22 RESET Safety Circuitry with Latched Fault TX Disable 02094-DSH-001-C Functional Description 3.2 * * * * * * * * * * Features High speed operation; suitable for SFP/SFF applications from 155Mbps to 2.0 Gbps. Typical rise/fall times < 110 ps. Supports Common Anode VCSEL, Common Cathode VCSEL, or FP LASER. May be used with or without a monitor photodiode. Programmable temperature compensation. Modulation output and bias output can be controlled using a few discrete resistors. Supports DDMI (SFF-8472) diagnostics. DC or AC coupled modulation drive. Peaking circuit to optimize VCSEL response. Low overshoot allows high extinction ratio with low jitter. Supports E-PON burst mode with no extra components Automatic Laser Power Control, with "Slow-Start". 3.3V or 5V operation 3.3 General Description 3.3.1 Detailed Description The M02094 laser driver consists of the following circuitry: an internal regulator, common anode/common cathode configuration control, bias current generator and automatic power control, data inputs, peaking adjust, modulation current control, modulator output, laser fail indication, disable control, and monitor outputs for the bias current, modulation current, and transmitted power. 3.3.2 Internal Regulator The M02094 contains an internal 3.3V regulator so high bit rate performance can be achieved with 5V or 3.3V power supply. When operating from a 5V supply (VCC is connected to +5V), an internal regulator provides a voltage of approximately 3.3V to the majority of the on-chip circuitry. The on-chip regulator is internally compensated, requiring no external components. When a 3.3V supply is used (VCC and VCC3 connected to 3.3V) the regulator is switched off and the internal circuitry is powered directly through the VCC3 supply pin. The decision as to whether or not the internal regulator is required is made via the VCC3SEL pin, which also determines whether the safety circuitry needs to monitor for proper +5V supply voltage. SVCC is sourced from VCC3 through a switch for common anode applications (this pin becomes IBOUT_CC in common cathode applications). When a fault condition is present, FAIL will assert and the switch sourcing SVCC will open so no current can pass through the laser. SVCC does not need any external capacitance, if capacitance to ground is added at SVCC it should be less than or equal to 100 pF. 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 23 M02094 Data Sheet VCC and VCC3 status are internally monitored by the M02094 during power-up and normal operation. During power-up the "slow-start" circuitry requires that VCC and VCC3 each reach an acceptable level before enabling bias or modulation current. Table 3-1. Pin Connection for 3.3V and 5V VCC Pin Connection For: Pins Dependent on VCC Voltage VCC = 3.3V 3.3.3 VCC = 5V VCC3 (pin 21) Connect to VCC Reference for CAPC and PEAKADJ CAPC (pin 20) Capacitor between CAPC and VCC3 or VCC Capacitor between CAPC and VCC3 (not VCC) PEAKADJ (pin 22) Connect to VCC3 or VCC to disable Connect to VCC3 to disable (not VCC) VCC3SEL (pin 4) Connect to VCC3 or VCC Connect to GND Common Cathode/Common Anode Configuration Control When CCSEL is programmed high, the M02094 is configured for common cathode lasers. When CCSEL is low, the M02094 is configured for common anode lasers. The state of the CCSEL pin determines: 1. 2. 3. 4. whether bias current is sourced or sunk whether monitor photodiode current is sunk or sourced whether internal termination resistors at OUT+ and OUT- are active whether the redundant safety switch disconnects VCC or GND from the output circuitry. The affected pins are OUT+, OUT-, SVCC/IBOUTCC, and SGND/IBOUTCA. The Table 3-2 below shows the configuration of each pin for the 2 states of CCSEL. 24 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Functional Description Table 3-2. Pin Connection for Common Anode and Common Cathode Laser Modes Pin Connection When: CCSEL = High Inactive Supply for laser and all output load components. Laser bias source current. Inactive Ground for laser and all output load components Inactive Inactive Laser bias sink current. Monitor photodiode source current Monitor photodiode sink current Controls Negative going edge of OUT- Controls Negative going edge of OUT-, (do not use) Internal 50 pull-up resistors on OUT+ and OUT- Active Inactive Ratio of Bias current to BIASMON current 13.5:1 45.7:1 30:1 65:1 SVCC Pin 18 Pins Dependent on CCSEL Setting CCSEL = Low IBOUTCC SGND Pin 14 IBOUTCA Pin 13 IPIN Pin 22 PEAKADJ Ratio of Modulation current to MODMON current 3.3.4 Bias Current Generator and Automatic Power Control The M02094 can either source or sink bias current for the laser diode depending on whether it is in common anode or common cathode mode. In common cathode mode (CCSEL high) IBOUTCC will source current. In common anode mode (CCSEL low) IBOUTCA will sink current. Regardless of whether the M02094 is configured for common anode or common cathode mode, the following information applies. To maintain constant average optical power, the M02094 incorporates a control loop to compensate for the changes in laser threshold current over temperature and lifetime. The bias current will be determined by the value of the external resistor RAPCSET and the transfer efficiency between the laser and monitor photodiode. The photo current from the monitor photodiode mounted in the laser package is sunk or sourced at IPIN. This photo current is mirrored and an equivalent current is sourced from pins TxPwrMON and APCSET. The APC loop adjusts the laser bias current (hence the monitor diode photo current) to maintain a voltage of 1.3V at APCSET. RAPCSET * IPIN = 1.3 V The APC loop has a time constant determined by CAPC, RAPCSET and the transfer efficiency between the laser and monitor photodiode. The larger the CAPC capacitor the lower the bandwidth of the loop and the larger the RAPCSET resistor the lower the bandwidth of the loop. In general, it is recommended that at least 2.2 nF of external capacitance be added externally between CAPC and VCC3 to assure loop stability. With use of a 2.2 nF capacitor, the bias current can reach 90% of its final value within 1 millisecond. 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 25 M02094 Data Sheet In Common Anode mode with a 2.2nF CAPC capacitor the APC loop bandwidth is less than 30 kHz for almost all combinations of RAPCSET and transfer efficiency., which should be adequate for bit rates of 155Mbps. (and all higher bit rates). In Common Cathode mode with a 2.2nF CAPC capacitor the APC loop bandwidth will be slightly higher, but should be less than 40 kHz for almost all combinations of RAPCSET and transfer efficiency. Contact the factory with your specific values of CAPC, RAPCSET, and transfer efficiency to determine the maximum APC loop bandwidth in your application. The bias generator also includes a bias current monitor mirror (BIASMON), whose output current is typically 1/ 45.7th of the bias current in common anode mode (CCSEL = low) or 1/13.5th of the bias current in common cathode mode (CCSEL = high). This pin can be connected through a resistor to ground. If this function is not needed this pin can be left open. The M02094 can be used without a monitor photodiode by connecting BIASMON to APCSET (see Figure 3-7 and Figure 4-3). In this case the M02094 will increase the bias current (hence the BIASMON current) to the laser until the voltage at APCSET is approximately 1.3V. 3.3.5 Data Inputs The inputs to the data buffers are self-biased through 4 k resistors to an internal voltage VTT which is approximately VCC3 - 1.3V. Both CML and PECL inputs signals can be AC coupled to the M02094, or in 3.3V applications PECL inputs can be DC coupled to the data inputs. In most applications the data inputs are AC coupled with controlled impedance pcb traces which will need to be terminated externally with a 100 or 150 resistor between the + and - inputs. 3.3.6 Peak Adjust Some VCSELs do not turn off quickly without peaking the negative going edge. In common cathode applications, peaking on this edge can be added with a resistor connected between the PEAKADJ input and GND. The amount of peaking is approximately Peaking current = 4 * (1.3V / resistance to ground). The resistance to ground should be between 2k and 20k. (Which will result in a peaking currents from 2.6mA to 260A.) Peaking control can be disabled by connecting PEAKADJ to VCC3, resulting in no peaking current and reducing supply current by approximately 2mA. In common anode configuration the PEAKADJ pin should be connected to VCC3. Note: Unlike the rest of the signal currents in the M02094, the output Peak Adjust current is unbalanced (singlesided drive). The designer should be aware that the use of peaking may result in unwanted EMI emissions. If EMI problems are traced to the use of peaking, high frequency decoupling (10pF capacitor or smaller) may be needed on the VCC line. 3.3.7 Modulation Control There are two programmable control lines for controlling the modulation current and its temperature compensation. These inputs can be programmed simply with a resistor to ground . The modulation current amplitude is controlled by the MODSET input pin. The modulation current is temperature compensated by the TCSLOPE input. 26 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Functional Description If the temperature compensation at TCSLOPE is disabled, the modulation output current is simply: IOUT = 42 x (1.3V / RMODSET) when CCSEL is low and IOUT = 22 x (1.3V / RMODSET) when CCSEL is high and a 50 VCSEL is used. Where RMODSET is the resistance from pin MODSET to ground. To temperature compensate the modulation current, choose RTCSLOPE to meet the following relationship: RTCSLOPE = 19.5*(TC)-1.5, where TC is the desired slope of the modulation current from 25C to 85C in%/C and RTCSLOPE is in k. If no temperature compensation is desired, leave RTCSLOPE open. In any case, RTCSLOPE will have negligible effect at M02094 case temperatures below 10C. For example: Given a common cathode VCSEL with a desired modulation current at low temperatures of 10mA and a temperature coefficient of -0.5%/C at high temperatures (which will require a laser driver temperature coefficient of +0.5%). Choose RMODSET = 22 x (1.3V / 10mA) = 2.8k. Choose RTCSLOPE =19.5*(0.5)-1.5 k = 55k. Figure 3-2. Selecting TCSLOPE Resistance in Common Anode Configuration RTCslope: 60.00 22k 27k 50.00 33k 39k 40.00 47k % change in modulation current 51k 30.00 62k 75k 82k 20.00 100k 120k 150k 10.00 220k 390k 0.00 750k -40 -20 0 20 40 60 80 open 100 -10.00 -20.00 -30.00 Ambient Temperature in degrees C 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 27 M02094 Data Sheet Figure 3-3. Selecting TCSLOPE Resistance in Common Cathode Configuration RTCslope: 70.0 27k 60.0 33k 39k 50.0 47k 51k 62k % change in modulation current 40.0 75k 82k 100k 30.0 120k 150k 180k 20.0 220k 10.0 390k 510k 0.0 open -40 -20 0 20 40 60 80 100 -10.0 -20.0 -30.0 Ambient Temperature in degrees C 3.3.8 Modulator (Figure 3-4) The output stages OUT+ and OUT- are designed to drive 25 output loads over a wide range of currents and circuit architectures. The VCSEL may be a common anode or common cathode device. The output can be AC, DC, or Differentially coupled depending on the supply voltage and laser configuration. In a common anode configuration with a VCSEL (Figure 4-1), OUT+ should be connected through a capacitor to the VCSEL. A pull-up resistor should be added in parallel to the VCSEL from SVCC to the OUT+ output. The dynamic impedance of the parallel combination of the VCSEL and pull-up resistor should be roughly 25 ohms. A 24 ohm pull-up resistor should also be added from SVCC to OUT- so the currents and voltage swings in the two outputs are balanced. In a common anode configuration with a Fabry-Perot laser (Figure 4-4), OUT+ may be AC, DC, or Differentially coupled to the laser cathode. A resistor should be added in series with the laser such that the dynamic impedance of the series combination of the laser and resistor should be roughly 25 ohms. A 24 ohm pull-up resistor to SVCC is needed on the OUT- output. For common cathode operation with a VCSEL (Figure 4-3), internal 50 ohm terminations are switched in between the OUT+ and OUT- outputs and VCC3. VCSELs with impedances from 25-75 can be simply AC coupled to the OUT- output with no additional load matching resistors. In this case OUT+ should be AC coupled to ground through 50. The VCSEL driver output stage is separately grounded from the rest of the circuitry (through GND0). At higher data rates (above 2Gb/s) GND0 may be connected to ground through a minimum of 2 nH of inductance to improve the 28 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Functional Description transient response. A ferrite can also provide the extra isolation (Murata BLM18HG471SN1 or equivalent recommended). Figure 3-4. Modulator Output 0.4pF 0.75 nH * 0.75 nH * OUT- OUT+ OUT+ and OUT- should not be driven below 0.7V GND0 (optional external inductance) 3.3.9 * Denotes bond wire internal to MLF package Fail Output The M02094 has a FAIL alarm output which is compatible with the TX_FAULT signalling requirements of common pluggable module standards. The ESD protection on this pin provides a true open collector output that can withstand significant variation in VCC when signalling between circuit boards. Also, if the M02094 loses power the FAIL output will continue to pull up and signal a fail condition. In a simple static protection scheme used by other ICs the protection diodes would clamp the FAIL signal to ground when the chip loses power. 3.3.10 TX Disable and Disable Delay Control The DIS pin is used to disable the transmit signal. When the transmit is disabled both the bias and modulation currents are off. The DIS input is compatible with TTL levels regardless of whether VCC = 5V or VCC = 3.3V. In most module applications a pull-up resistor to VCC between 4.7 k and 10 k is required. Because this pin has an internal 7 k resistor to VCC, no external pull-up resistor is required. The DISDLY pin is used in conjunction with the DIS pin to control bias current enable time. (The modulation current enable time is always less than 600 ns). Unless the DISDLY pin is programmed for burst mode, the APC loop enable time will be slow (less than 1 ms with a CAPC = 2.2 nF). When a capacitor C is added to the DISDLY pin, the slow-start circuitry is disabled for typically T = 3 * 106 (sec/F)* C (F) following the DIS high transition. If DIS transitions low during this time, the bias current will quickly return to within 90% of its final value (within less than 500 ns). If DIS transitions low after this time the slow-start circuitry will engage and the bias current will not return to its final value for approximately 1ms (depending on the CAPC capacitor). 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 29 M02094 Data Sheet 3.3.11 Burst Mode Operation (Figure 3-5) The M02094 will meet the timing requirements of EPON with the addition of a capacitor at DISDLY (see paragraph above and Figure 3-5). As shown in Figure 4-4, the laser should be DC coupled to OUT+. VCC may be 3.3V or 5V. Figure 3-5. DIS and DISLY Timing EPO N Burst M ode O peration D IS D ISD LY IBIAS O U T O U T+ t_off BM < 500ns t_on BM < 500ns for I M O D > 10m A Norm al O peration, (slow-start whenever part enabled) D IS D ISD LY t_on < 1m s, depending on C APC IBIAS O U T O U T+ t_off < 10s 30 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Functional Description 3.3.12 Video Operation The M02094 can be used to transmit video optical data even in the presence of the pathological pattern. This is done by fully DC coupling the signal from the input to the laser output. In most data communications applications, AC coupling occurs at three points in a laser driver schematic: the data inputs, the APC control, and coupling the modulation current to the laser. In the M02069, DC coupling can be used at all three of these points. With DC coupling the laser output will not be a function of the data input one/zero density. The data inputs can be DC coupled using PECL or CML levels. The APC of the bias current is controlled by feedback from the monitor photodiode in the laser package in most communications applications. In video applications this monitor photodiode should not be used if the pathological pattern may occur. Instead, the APC should be controlled in an "open loop" configuration. (Open loop simply means a monitor photodiode is not used). In the open loop configuration the APC is controlled by a resistor or a thermistor network or a look-up table and DAC. This removes AC time constants from the bias current. In Figure 3-6 the BIASmon pin is connected to the APCset pin. In this case the bias current is: IBIAS = 45.7 x (1.35V / RAPCSET) The modulation current output OUT+ can be DC coupled to the laser as shown in Figure 3-6. There are no AC time constants in the modulation current amplitude in this configuration. Video Application Block Diagram VC C DIN + V CC3 V CC3 VCC3 V CC PEAKAD J Figure 3-6. Internal Power Bus Internal 3.3V reg. SV CC OUTInput Buffer Output Buffer Laser Driver OUT+ GND0 DIN V CC3 -1.3V IB OUT_CA IPIN CC SEL CAPC DISDLY APCSET MODSET Automatic Power Control (laser bias current) TxPwr MON Connect to V CC when V CC = 3.3V MODMON TCSLOPE VCC3SEL RESET FAIL DIS Modulation Control BIASMON Safety Circuitry with Latched Fault TX Disable For V CC=3.3V, tie VCC3 to V CC. V CC3 Connect to GND when V CC = 5V 3.3.13 Current Monitors To facilitate complying with laser safety and DDMI1 requirements, output monitors are provided for transmit power (TxPwrMON), bias (BIASMON), and modulation current (MODMON). These outputs will source current proportional to the emitted optical power (TxPwrMON) the bias current (BIASMON) and modulation current (MODMON). 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 31 M02094 Data Sheet To use these pins they should be terminated with a resistor to ground that sets the desired full-scale voltage (not to exceed 2.5V). If the outputs of these monitors are not needed, TxPwrMON, BIASMON, and MODMON can all be left floating and the chip current consumption will be reduced by the value of the monitor currents. 3.4 Laser Eye Safety Using this laser driver in the manner described herein does not ensure that the resulting laser transmitter complies with established standards such as IEC 825. Users must take the necessary precautions to ensure that eye safety and other applicable standards are met. Note that determining and implementing the level of fault tolerance required by the applications that this part is going into is the responsibility of the transmitter designer and manufacturer since the application of this device cannot be controlled by Mindspeed. 1 Digital Diagnostic Monitoring Interface for Optical Tranceivers, defined in SFF-8472. 32 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Functional Description 3.4.1 Safety Circuitry Safety Circuitry in the M02094 will disable the modulation and bias current and assert the FAIL output immediately upon detecting a fault condition. In addition, the supply voltage that sources or sinks the laser current (SVCC or SGND) will immediately go open circuit and prevent any current from passing through the laser. Fault conditions checked by the M02094 include shorts to ground or VCC of all pins which can increase the laser modulation or bias current. For an initialization or power-up sequence to be successful, all the fault detection monitors must signal that the chip is "healthy". When DIS goes low, pins are checked for shorts to ground or VCC and a FAIL condition is latched if there is a fault. If the state of the pins is OK, a one-shot at the reset pin begins a countdown which will latch a FAIL condition if the bias current has not stabilized to an acceptable level during the one-shot time. The one-shot can be extended with an external capacitor connected from the RESET pin to ground. The one-shot1 width is approximately TONE-SHOT = 3 ms + (0.3 ms/pF)x(external capacitance). Figure 3-7. Safety Circuit Block Diagram DIS If chip is `healthy', then Enable the outputs and Start 3msec Reset Pulse(one-shot) AND AND OUTPUT_ENABLE AND Latch for CrudeFaults VccOK Detection: SRlatch: AND 5v Mode: Reset Q Vcc Pin Set 5v Hi/Lo Limits FAILout (open-collector) AND Vcc3 Pin Latch for Bias_OK Delay 3.3v Hi/Lo Limits 3.3v Mode: VCC_OK ONE-SHOT: t=0 Start SRlatch: 3ms + Tcap Reset PULSE OR Q Vcc Pin RESET 5v Hi/Lo Limits NOTE: Pulse stays high if Reset pin is GNDed. Set `1' AND optional cap for longer T_init Vcc3 Pin 3.3v Hi/Lo Limits CrudeFaults Detection: OutP Cmpc MODset > 300mV > 300mV > 300mV IbiasOut > 300mV (2061) BiasOK Detection: Window Compare: CrudeFaults_OK HI Limit MPCset OR BIAS_OK IboutCA > 300mV (2069 - Common Anode) IboutCC < (Vcc3 - 300mV) LOW Limit (2069 - Common Cathode) 1.The one-shot is actually comprised of an oscillator and 10-bit counter. 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 33 M02094 Data Sheet 3.5 Fault Conditions This section describes the M02094 operating modes during fault conditions. Over voltage, under voltage, pins shorted to VCC and pins shorted to ground are included in the fault Table 3-3. Table 3-3. Pin Name Circuit Response to Single-Point Fault Conditions Circuit Response to Over-voltage Condition or Short to VCC Circuit Response to Under-Voltage Condition or Short to Ground VCC Bias and modulation outputs are disabled once VCC rises above the supply detection (high voltage) threshold (see Table 1-3) Bias and modulation outputs are disabled once VCC drops below the supply detection (low voltage) threshold DIN+, DIN- The APC loop will attempt to compensate for the change in The APC loop will attempt to compensate for the change in output power. If the APC loop can not maintain the set average output power. If the APC loop can not maintain the set average power, a fault state occurs.(1,2,3) power, a fault state occurs.(1,2,3) VCC3SEL Does not affect laser power. Does not affect laser power. DIS Bias and modulation outputs are disabled. SVCC is opened when CCSEL is low or floating (or SGND is opened when CCSEL is high) Does not affect laser power (normal condition for circuit operation). FAIL Does not affect laser power. Does not affect laser power. RESET Does not affect laser power. Does not affect laser power. MODMON Does not affect laser power. Does not affect laser power. BIASMON Does not affect laser power. Does not affect laser power. TxPWRMON Does not affect laser power. Does not affect laser power. APCSET (1) A fault state occurs. A fault state occurs.(1) IPIN A fault state occurs.(1) A fault state occurs.(1) IBOUTCA(3) The laser will be turned off, then a fault state occurs.(1) A fault state occurs.(1) IBOUTCC(4) A fault state occurs.(1) The laser will be turned off, then a fault state occurs.(1) OUT+(3) Laser modulation is prevented; the APC loop will increase the bias current to compensate for the drop in laser power if it is DC coupled. If the set output power can not be obtained, a fault state occurs.(1,2) A fault state occurs.(1) OUT-(4) Does not affect laser power during common cathode operation because output is AC coupled. Does not affect laser power during common cathode operation because output is AC coupled. SVCC(3) Does not affect laser power. Laser bias current will be shut off and a fault state occurs.(1) CAPC Laser bias current will be shut off, then a fault state occurs.(1) A fault state occurs.(1) VCC3 Bias and modulation outputs are disabled once VCC3 rises above the supply detection (high voltage) threshold Bias and modulation outputs are disabled once VCC3 drops below the supply detection (low voltage) threshold PEAKADJ Does not affect laser power. Does not affect laser power CCSEL Normal operation for common cathode configuration. If the M02094 is configured for common anode drive, a fault state will occur.(1) Normal operation for common anode configuration. If the M02094 is configured for common cathode drive, a fault state will occur.(1) MODSET When the laser is DC coupled in common anode configuration, A fault state occurs.(1) the APC loop will attempt to compensate for the drop in output power. If the APC loop can not maintain the set average power, a fault state occurs.(1,2) 34 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Functional Description Table 3-3. Pin Name Circuit Response to Single-Point Fault Conditions Circuit Response to Over-voltage Condition or Short to VCC Circuit Response to Under-Voltage Condition or Short to Ground TCSLOPE Does not affect laser power. When the laser is DC coupled in common anode configuration, the APC loop will attempt to compensate for any change in output power. If the APC loop can not maintain the set average power, a fault state occurs.(1,2) DISDLY Does not affect laser power. Does not affect laser power. Notes: 1. A fault state will assert the FAIL output, disable bias and modulation outputs and will either open the switch at SVCC (CCSEL=high) or SGND (CCSEL=low). 2. Does not affect laser power when the output is AC coupled to the laser. 3. Does not affect laser power during common cathode operation. 4. Does not affect laser power during common anode operation. 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 35 M02094 Data Sheet 36 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C 4.0 Applications 4.1 EPON FTTH modules Gigabit Ethernet modules 1G/2G Fibre Channel modules Digital Video Application Diagram, Common Anode VCSEL (may be DC coupled, but extra bias current will be required for the pull-up resistor on OUT+) V VCC DIN + V CC3 V CC3 CC3 V CC V CC3 AD J Figure 4-1. PEAK * * * * Applications Internal Power Bus Internal 3.3V reg. SV C C OUT- Input Buffer Output Buffer Laser Driver OUT+ GND0 DIN V CC3 -1.3V IB OUT_CA IPIN APC CC SEL C DISDLY APCSET MODMON Automatic Power Control (laser bias current) TxPwr MON Connect to V CC when V CC = 3.3V MODSET TCSLOPE VCC3SEL RESET FAIL DIS Modulation Control BIASMON Safety Circuitry with Latched Fault TX Disable For VCC=3.3V, tie V CC3 to VCC. V CC3 Connect to GND when V CC = 5V 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 37 M02094 Data Sheet Application Diagram, Common Cathode VCSEL PEAKAD J V CC3 V CC V CC V CC3 Figure 4-2. Internal Power Bus Internal 3.3V reg. OUT+ Input Buffer DIN+ Output Buffer Laser Driver OUTGND0 DINV CC3 -1.3V IBOUT_CC SGND IPIN CCSEL Connect to V CC when V CC = 3.3V CAPC DISDLY TxPwr MON BIASMON APCSET Automatic Power Control (laser bias current) MODMON TCSLOPE MODSET Modulation Control VCC3 SEL FAIL DIS RESET Safety Circuitry with Latched Fault TX Disable V CC For VCC=3.3V, tie VCC3 to VCC. VCC3 Connect to GND when V CC = 5V 38 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C Applications Application Diagram, Common Cathode VCSEL w/o Monitor Diode PEAKADJ V CC3 V CC V CC V CC3 Figure 4-3. Internal Power Bus Internal 3.3V reg. OUT+ Output Buf f er Input Buf f er DIN+ Laser Driv er OUTGND0 DINV CC3 -1.3V IBOUT_CC SGND IPIN CCSEL Connect to V CC when V CC =3.3V CAPC DISDLY TxPwrMON BIASMON APCSET Automatic Power Control (laser bias current) MODMON TCSLOPE MODSET Modulation Control VCC3SEL FAIL DIS RESET Saf ety Circuitry with LatchedFault TX Disable V CC3 For V CC=3.3V, tie V CC3 to V CC. V CC3 Connect toGND when V CC = 5V 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 39 M02094 Data Sheet Application Diagram, Common Anode FP Laser, DC Coupling VC C DIN + V CC3 V CC3 VCC3 V CC PEAKAD J Figure 4-4. Internal Power Bus Internal 3.3V reg. SV C C OUT- Input Buffer Output Buffer Laser Driver OUT+ GND0 DIN V CC3 -1.3V IB OUT_CA IPIN CAPC DISDLY SET APC MODMON SLOPE Automatic Power Control (laser bias current) TxPwr MON Connect to V CC when V CC = 3.3V MODSET TC VCC3SEL RESET FAIL DIS Modulation Control BIASMON Safety Circuitry with Latched Fault TX Disable CC SEL For V CC=3.3V, tie VCC3 to V CC. For EPON operation, add a capacitor to GND at DISDLY. V CC3 Connect to GND when V CC = 5V 40 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C 5.0 Packaging Specification 5.1 Figure 5-1. Package Specification QFN24 Package Information Note: View is for a 20 pin package. All dimensions in the tables apply for the 24 pin package 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 41 M02094 Data Sheet 42 Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 02094-DSH-001-C (c) 2003, 2004, 2005 Mindspeed TechnologiesTM, Inc. All rights reserved. Information in this document is provided in connection with Mindspeed TechnologiesTM ("MindspeedTM") products. These materials are provided by Mindspeed as a service to its customers and may be used for informational purposes only. Except as provided in Mindspeed's Terms and Conditions of Sale for such products or in any separate agreement related to this document, Mindspeed assumes no liability whatsoever. Mindspeed assumes no responsibility for errors or omissions in these materials. Mindspeed may make changes to specifications and product descriptions at any time, without notice. Mindspeed makes no commitment to update the information and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to its specifications and product descriptions. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. THESE MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, RELATING TO SALE AND/OR USE OF MINDSPEED PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, CONSEQUENTIAL OR INCIDENTAL DAMAGES, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. MINDSPEED FURTHER DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. MINDSPEED SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS, WHICH MAY RESULT FROM THE USE OF THESE MATERIALS. Mindspeed products are not intended for use in medical, lifesaving or life sustaining applications. Mindspeed customers using or selling Mindspeed products for use in such applications do so at their own risk and agree to fully indemnify Mindspeed for any damages resulting from such improper use or sale. 02094-DSH-001-C Mindspeed TechnologiesTM Mindspeed Proprietary and Confidential 43 M02094 Data Sheet www.mindspeed.com General Information: U.S. and Canada: (800) 854-8099 International: (949) 579-3000 Headquarters - Newport Beach 4000 MacArthur Blvd., East Tower Newport Beach, CA. 92660