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19-1550; Rev 0; 12/99
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
General Description
The MAX3286/MAX3296 series of products are highspeed laser drivers for fiber optic LAN transmitters, optimized for Gigabit Ethernet applications. Each device contains a bias generator, laser modulator, and comprehensive safety features. Automatic power control (APC) adjusts the laser bias current to maintain average optical power at a constant level, regardless of changes in temperature or laser properties. For lasers without a monitor photodiode, these products offer a constant-current mode. The circuit can be configured for use with conventional shortwave (780nm to 850nm) or longwave (1300nm) laser diodes, as well as verticalcavity surface-emitting lasers (VCSELs). The MAX3286 series (MAX3286/MAX3287/MAX3288/ MAX3289) is optimized for operation at 1.25Gbps, and the MAX3296 series (MAX3296/MAX3297/MAX3298/ MAX3299) is optimized for 2.5Gbps operation. Each device can switch 30mA of laser modulation current at the specified data rate. Adjustable temperature compensation is provided to keep the optical extinction ratio within specifications over the operating temperature range. This series of devices is optimized to drive lasers packaged in low-cost TO-46 headers. Deterministic jitter (DJ) for the MAX3286 is typically 22ps, allowing a 72% margin to Gigabit Ethernet DJ specifications. These laser drivers provide extensive safety features to guarantee single-point fault tolerance. Safety features include dual enable inputs, dual shutdown circuits, and a laser-power monitor. The safety circuit detects faults that could cause dangerous light output levels. A programmable power-on reset pulse initializes the laser driver at start-up. The MAX3286/MAX3296 are available in a compact, 5mm x 5mm, 32-pin TQFP package or in die form. The MAX3287/MAX3288/MAX3289 and MAX3297/MAX3298/ MAX3299 are available in smaller 16-pin TSSOP-EP packages, which are ideal for small form-factor optical modules. o 7ps Deterministic Jitter (MAX3296) 22ps Deterministic Jitter (MAX3286) o +3.0V to +5.5V Supply Voltage o Selectable Laser Pinning (common cathode or common anode) (MAX3286/MAX3296) o 30mA Laser Modulation Current o Temperature Compensation of Modulation Current o Automatic Laser Power Control or Constant Bias Current o Integrated Safety Circuits o Power-On Reset Signal o 16-Pin TSSOP-EP Package Available
Features
MAX3286-MAX3289/MAX3296-MAX3299
Ordering Information
PART MAX3286CHJ MAX3286C/D TEMP. RANGE 0C to +70C 0C to +70C PIN-PACKAGE 32 TQFP (5mm x 5mm) Dice*
Ordering Information continued at end of data sheet. *Dice are designed to operate from TJ = 0C to +110C, but are tested and guaranteed only at TA = +25C.
Pin Configurations
TOP VIEW
GND 1 FLTDLY 2 VCC 3 IN+ 4 IN- 5 GND 6 REF 7 MD 8
16 TC 15 MODSET 14 VCC
Applications
Gigabit Ethernet Optical Transmitter Fibre Channel Optical Transmitter ATM LAN Optical Transmitter
MAX3287 MAX3289 MAX3297 MAX3299
13 OUT12 OUT+ 11 VCC 10 BIASDRV 9 SHDNDRV
TSSOP-EP* *Exposed paddle is connected to GND. Pin Configurations continued at end of data sheet.
Typical Application Circuits and Selector Guide appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
ABSOLUTE MAXIMUM RATINGS
Supply Voltage at VCC ..........................................-0.5V to +7.0V Voltage at EN, EN, PORDLY, FLTDLY, LV, IN+, IN-, REF, POL, POL, MD, MON, BIASDRV, MODSET, TC..........................................................-0.5V to (VCC + 0.5V) Voltage at OUT+, OUT- .........................(VCC - 2V) to (VCC + 2V) Current into FAULT, FAULT, POR, SHDNDRV....-1mA to +25mA Current into OUT+, OUT- ....................................................60mA Continuous Power Dissipation (TA = +70C) 32-Pin TQFP (derate 14.3mW/C) ...............................1100mW 16-Pin TSSOP (derate 27mW/C)................................2162mW Operating Temperature Range...............................0C to +70C Operating Junction Temperature Range ..............0C to +150C Processing Temperature (die) .........................................+400C Storage Temperature Range .............................-55C to +150C Lead Temperature (soldering, 10s) .................................+300C
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.
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +5.5V, TA = 0C to +70C, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25C, RTC = open; see Figure 1a.) PARAMETER Supply Current Data Input Voltage Swing TTL Input Current TTL Input High Voltage TTL Input Low Voltage FAULT, FAULT Output High Voltage FAULT, FAULT Output Low Voltage BIAS GENERATOR (Note 1) BIASDRV Current, Shutdown BIASDRV Current Sink BIASDRV Current Source REF Voltage MD Nominal Voltage MD Voltage During Fault MD Input Current MON Input Current POWER-ON RESET POR Threshold POR Hysteresis FAULT DETECTION REF Fault Threshold MD High Fault Threshold MD Low Fault Threshold MON Fault Threshold MODSET, TC Fault Threshold 2 _______________________________________________________________________________________ MAX3286/MAX3288/MAX3296/MAX3298 VMD + 5% VMD - 20% VCC 600 2.95 VMD + 20% VMD - 5% VCC 480 0.8 V LV = GND LV = open 3.9 2.65 150 4.5 3.0 V mV VMD EN = GND FAULT = low, VBIASDRV 0.6V FAULT = low, VBIASDRV VCC - 1V IREF 2mA, MON = VCC APC loop is closed Common-cathode configuration Common-anode configuration Normal operation (FAULT = low) VMON = VCC 2 -2 -1 0.8 0.8 2.45 1.55 2.65 1.7 0.4 VCC - 0.8 0.16 0.44 2 6 2.85 1.85 1.2 1 A mA V V V A A VIH VIL VOH VOL IOH = -100A IOL = 1mA 2.4 0.4 SYMBOL ICC VID CONDITIONS Figure 1a, RMOD = 1.82k Total differential signal, peak-peak, Figure 1a 0 VPIN VCC 200 -100 2.0 0.8 MIN TYP 52 MAX 75 1660 100 UNITS mA mV A V V V V
mV V
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +5.5V, TA = 0C to +70C, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25C, RTC = open; see Figure 1a.) PARAMETER SHUTDOWN ISHDNDRV = 10A, FAULT asserted Voltage at SHDNDRV LASER MODULATOR Data Rate Minimum Laser Modulation Current Maximum Laser Modulation Current Tolerance of Modulation Current Modulation-Current Edge Speed RL 25 RMOD = 1.9k (iMOD = 30mA) RMOD = 13k (iMOD = 5mA) 20% to 80% MAX3286 series MAX3296 series RMOD = 13k (iMOD = 5mA) MAX3286 series RMOD = 4.1k (iMOD = 15mA) RMOD = 1.9k (iMOD = 30mA) RMOD = 13k (iMOD = 5mA) MAX3296 series RMOD = 4.1k (iMOD = 15mA) RMOD = 1.9k (iMOD = 30mA) Random Jitter, RMS (Note 3) Shutdown Modulation Current Modulation-Current Temperature Coefficient Differential Input Resistance Output Resistance Input Bias Voltage LASER SAFETY CIRCUIT PORDLY = open POR Delay Fault Time Glitch Rejection at MD tPORDLY tFAULT CPORDLY = 0.01F, MAX3286/MAX3296 only (Note 4) 10 0.3 3 1.25 5.5 22 20 s ms s s 3 Single ended Tempco = max, RMOD = open; Figure 5 Tempco = min, RTC = open; Figure 5 620 42 MAX3286 series MAX3296 series 30 -10 -15 130 90 46 29 22 14 8 7 2 2 15 4000 50 800 50 VCC - 0.3 980 58 10 15 220 150 65 45 35 ps 35 22 20 8 4 200 ps A ppm/C V MAX3286 series MAX3296 series 1.25 2.5 Gbps ISHDNDRV = 15mA, FAULT not asserted ISHDNDRV = 1mA, FAULT not asserted VCC - 0.4 0 0 VCC - 1.2 VCC - 2.4 V SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX3286-MAX3289/MAX3296-MAX3299
2
mA mA % ps
Deterministic Jitter (Note 2)
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3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +5.5V, TA = 0C to +70C, unless otherwise noted. Typical values are at VCC = +3.3V and TA = +25C, RTC = open; see Figure 1a.) PARAMETER FLTDLY Duration SYMBOL tFLTDLY CFLTDLY = 0 CFLTDLY = 270pF MAX3286/MAX3296 only, Figure 1b MAX3286/MAX3296 only, Figure 1b MAX3286/MAX3296 only, Figure 1b CONDITIONS MIN 0.2 100 TYP 1 140 6 10 MAX UNITS s
EN or EN Minimum Pulse Width tEN_RESET Required to Reset a Latched Fault FAULT Reset After EN, EN, or POR Transition SHDNDRV Asserted After EN = low or EN = high tRESET tSHUTDN
ns
1 3.5
2 5.5
s s
Note 1: "Common-anode configuration" refers to a configuration where POL = GND, POL = VCC, and an NPN device is used to set the laser bias current. "Common-cathode configuration" refers to a configuration where POL = VCC, POL = GND, and a PNP device is used to set the laser bias current. Note 2: Deterministic jitter measured with a repeating K28.5 bit pattern 00111110101100000101. Deterministic jitter is the peak-topeak deviation from the ideal time crossings per ANSI X3.230, Annex A. Note 3: For Fibre Channel and Gigabit Ethernet applications, the peak-to-peak random jitter is 14.1 times the RMS jitter. Note 4: Delay from a fault on MD until FAULT is asserted high.
Typical Operating Characteristics
(TA = +25C, unless otherwise noted.)
POR DELAY vs. CPORDLY
MA3286 toc01
FLTDLY DURATION vs. CFLTDLY
MA3286 toc02
EYE DIAGRAM
MAX3286 toc03
100k
10k
10k
1k DELAY (s) DELAY (s) 10 100 1k CAPACITANCE (pF) 10k 100k 1k
100
100
10
10
1
1 1 10 100 CAPACITANCE (pF) 1k 10k 50ps/div 2.5Gbps, 1310nm Laser, 27 - 1 PRBS, iMOD = 15mA
4
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3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
Typical Operating Characteristics (continued)
(TA = +25C, unless otherwise noted.)
EN STARTUP (COMMON-ANODE CONFIGURATION)
MA3286 toc04
MAX3286-MAX3289/MAX3296-MAX3299
MD SHUTDOWN
MA3286 toc05
EYE DIAGRAM
MA3286 toc06
EN
MD
FAULT BIASDRV
FAULT
SHDNDRV
OPTICAL OUTPUT
5s/div
OPTICAL OUTPUT
10s/div
50ps/div 2.5Gbps, 1310nm LASER, 27 - 1 PRBS, imod = 15mA
Pin Description
PIN MAX3287 MAX3297 MAX3289 MAX3299 -- -- -- -- 1, 6 -- -- -- NAME FUNCTION
MAX3286 MAX3296 1 2, 16 3 4 5, 14, 22, 30 6 7 8
MAX3288 MAX3298 -- -- -- -- 1, 6 -- -- --
FAULT N.C. FAULT POR GND EN EN PORDLY
Inverting Fault Indicator. See Table 1. No Connect Noninverting Fault Indicator. See Table 1. Power-On Reset. POR is a TTL-compatible output. See Figure 14. Ground Enable TTL Input. Laser output is enabled only when EN is high and EN is low. If EN is left unconnected, the laser is disabled. Inverting Enable TTL Input. Laser output is enabled only when EN is low or grounded and EN is high. If EN is left unconnected, the laser is disabled. Power-On Reset Delay. To extend the delay for the power-on reset circuit, connect a capacitor to PORDLY. See Design Procedure. Fault Delay Input. Determines the delay of the FAULT and FAULT outputs. A capacitor attached to FLTDLY ensures proper start-up. (See Typical Operating Characteristics.) FLTDLY = GND: holds FAULT low and FAULT high. When FLTDLY = GND, EN = high, EN = low, and VCC is within the operational range, the safety circuitry is inactive. Low-Voltage Operation. Connect to GND for 4.5V to 5.5V operation. Leave open for 3.0V to 5.5V operation. Supply Voltage
9
2
2
FLTDLY
10 11, 25, 26, 29
-- 3, 11, 14
-- 3, 11, 14
LV VCC
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3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
Pin Description (continued)
PIN MAX3287 MAX3297 MAX3289 MAX3299 4 5 7 -- -- -- 8 -- 9 10 12 13 15 16 EP NAME FUNCTION
MAX3286 MAX3296 12 13 15 17 18 19 20 21 23 24 27 28 31 32 --
MAX3288 MAX3298 4 5 7 -- -- -- 8 9 -- 10 12 13 15 16 EP
IN+ INREF POL POL I.C. MD MON SHDN-DRV BIASDRV OUT+ OUTMODSET TC Exposed Paddle
Noninverting Data Input Inverting Data Input Reference Voltage. A resistor connected at REF to MD determines the laser power when APC is used with common-cathode lasers. Polarity Input. POL is used for programming the laser-pinning polarity. (Table 4) Inverting Polarity Input. POL is used for programming the laser-pinning polarity (Table 4) Internally Connected. Do not connect. Monitor Diode Connection. MD is used for automatic power control. Laser Bias Current Monitor. Used for programming laser bias current in VCSEL applications. Shutdown Driver Output. Provides a redundant laser shutdown. Bias-Controlling Transistor Driver. Connects to the base of an external PNP or NPN transistor. Modulation-Current Output. See Typical Application Circuits. Modulation-Current Output. See Typical Application Circuits. Modulation-Current Set. The resistor at MODSET programs the temperature-stable component of the laser modulation current. Temperature-Compensation Set. The resistor at TC programs the temperature-increasing component of the laser modulation current. Ground. This must be soldered to the circuit board ground for proper thermal performance. See Layout Considerations.
Table 1. Typical Fault Conditions
PIN VCC REF POL and POL MON MD EN and EN MODSET and TC FAULT CONDITION LV = open and VCC < 3V; LV = GND and VCC < 4.5V VREF > 2.95V POL = POL VMON < VCC - 540mV VMD > 1.15 * VMD(nom), VMD < 0.85 * VMD(nom) EN = low or open, EN = high or open VMODSET and VTC 0.8V
Table 2. LV Operating Range
LV Open Grounded OPERATING VOLTAGE RANGE (V) >3.0 >4.5
6
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3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
VCC ICC IOUT
FERRITE BEAD* 0.01F
VOLTS VIN+ DIFFERENTIAL INPUT 100mVp-p MIN 830mVp-p MAX RESULTING SIGNAL 200mVp-p MIN 1660mVp-p MAX
0.01F VCC OUTOUT+ VCC 50 RL 25 L = 3.9nH iMOD VID = VIN+ - VINVIN-
MAX3286 VCC MAX3296 50
CURRENT L = 3.9nH iMOD
IN+ VID INMODSET *MURATA BLM11HA102 MODULATION CONTROL TC BIASDRV (OPEN) iMOD3/2 LASER EQUIVALENT LOAD
TIME RL.= 25
RMOD
Figure 1a. Output Load for AC Specification
_______________Detailed Description
VCC POR tFAULT FAULT SHDNDRV OPTICAL OUT EN FAULT ON MD NOTE: TIMING IS NOT TO SCALE. RESET BY EN SHUTDOWN BY EN tRESET tSHUTDN tPORDLY
The MAX3286/MAX3296 series of laser drivers contain a bias generator with automatic power control (APC), laser modulator, power-on reset (POR) circuit, and safety circuitry (Figures 2a and 2b).
Bias Generator
Figure 3 shows the bias generator circuitry containing a power-control amplifier, controlled reference voltage, smooth-start circuit, and window comparator. The bias generator combined with an external PNP or NPN transistor provides DC laser current to bias the laser in a light-emitting state. When there is a monitor diode (MD) in the laser package, the APC circuitry adjusts the laser-bias current to maintain average power over tem-
tEN_RESET
Figure 1b. Fault Timing
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7
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
LV PORDLY EN EN FLTDLY POL POL MON MD IN+ INLASER MODULATOR TC MODSET BIAS GENERATOR SAFETY POR CIRCUIT POR FAULT FAULT SHDNDRV MD BIASDRV REF OUT+ OUT-
perature and changing laser properties. The MD input is connected to the anode or cathode of a monitor photodiode or to a resistor-divider, depending on the specific application circuit. Three application circuits are supported: common-cathode laser with photodiode, common-cathode laser without photodiode, and commonanode laser with photodiode (as shown in the Design Procedure). The POL and POL inputs determine the laser pinning (common cathode, common anode) (Table 4). The smooth-start circuitry prevents current spikes to the laser during power-up or enable; this ensures compliance with safety requirements and extends the life of the laser. The power-control amplifier drives an external transistor to control the laser bias current. In a fault condition, the power-control amplifier's output is disabled (high
Figure 2a. Simplified Laser Driver Functional Diagram
LV PORDLY POR FAULT FAULT VCC - 0.54V FLTDLY EN EN SAFETY CIRCUITRY 1.97V MAX3286 MAX3296 1.7V REF CONTROLLED REFERENCE GENERATOR MON SHDNDRV REF
POR CIRCUIT
1.53V POL POL IN+ ININPUT BUFFER 50 LASER MODULATOR VCC MODULATION CURRENT GENERATOR TC RTC MODSET RMOD 50 SMOOTH START +1.7V
MD BIASDRV
BIAS GENERATOR OUTOUT+
Figure 2b. Laser Driver Functional Diagram 8 _______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
impedance). This ensures that the PNP or NPN transistor is turned off, removing the laser-bias current. (See Applications Information.) The REF pin provides a controlled reference voltage dependent upon the voltage at MON. The voltage at REF is VREF = 2.65 - 2.25(VCC - VMON). A resistor connected at REF determines the laser power when APC is used with common-cathode lasers. See the Design Procedure for setting the laser power.
POL POL ENABLE MD
MAX3286-MAX3289/MAX3296-MAX3299
POLARITY _FAULT
+1.53V GLITCH REJECT +1.97V POWER CONTROL AMPLIFIER +1.7V WINDOW COMPARATOR MD FAULT
SMOOTH START
ENABLE BIASDRV
Modulation Circuitry
The modulator circuitry consists of an input buffer, current generator, and high-speed current switch (Figure 4). The modulator drives up to 30mA of modulation current into a 25 load. Many of the modulator performance specifications depend on the total modulator current (IOUT) (Figure 1a). To ensure good driver performance, the voltage at OUT+ and OUT- must not be less than VCC - 1V. The amplitude of the modulation current is set with resistors at the MODSET and TC (temperature coefficient) pins. The resistor at MODSET (RMOD) programs the temperature-stable portion of modulation current, while the resistor at TC (R TC) programs the temperatureincreasing portion of the modulation current. Figure 5 shows modulation current as a function of temperature for two extremes: RTC is open (the modulation current has zero temperature coefficient) and R MOD is open (the modulation temperature coefficient is 4000ppm). Intermediate tempco values of modulation current can be obtained as described in the Design Procedure.
REF
CONTROLLED REFERENCE VOLTAGE VREF = 2.65 - 2.25 (VCC - VMON)
MON
2.95V
REF_FAULT
MONITOR_FAULT
VCC - 540mV
Figure 3. Bias Generator Circuitry
VCC
MAX3286 MAX3296
IN+ INPUT BUFFER CURRENT SWITCH
50
50 OUT+ OUT-
400
VCC - 0.3V 400 INMODULATION CURRENT GENERATOR ENABLE CURRENT AMPLIFIER 96X
Safety Circuitry
The laser driver can be used with two popular safety systems. APC maintains laser safety using local feedback. Safety features monitor laser driver operation and force a shutdown if a fault is detected. The shutdown condition is latched until reset by a toggle of EN, EN, or power. Another safety system, Open Fiber Control (OFC), uses safety interlocks to prevent eye hazards. To accommodate the OFC standard, the MAX3286/MAX3296 series provide dual enable inputs and dual fault outputs. The safety circuitry contains fault detection, dual enable inputs, latched fault outputs, and a pulse generator (Figure 6). Safety circuitry monitors the APC circuit to detect unsafe levels of laser emission during single-point failures. A single-point failure can be a short to V CC or GND, or between any two IC pins.
4000ppm/C REFERENCE
1.2V REFERENCE MOD_FAULT
TC_FAULT
0.8V
0.8V
TC RTC
MODSET RMOD
Figure 4. Laser Modulator Circuitry _______________________________________________________________________________________ 9
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
Pulse Generator During start-up, the laser is not emitting light and the APC loop is not closed, triggering a fault signal. To allow start-up, an internal fault-delay pulse disables the safety system for a programmable period of time, allowing the driver to begin operation. The length of the pulse is determined by the capacitor connected at FLTDLY and should be set 5 to 10 times longer than the APC time constant. The internal safety features can be disabled by connecting FLTDLY to GND. Note that EN must be high, EN must be low, and VCC must be in the operational range for laser operation. Fault Detection The MAX3286/MAX3296 series have extensive and comprehensive fault-detection features. All critical
1.3 1.2 iMOD/(iMOD AT+ 52C) 1.1 1.0 0.9 0.8 0.7 0.6 0 10 20 30 40 50 60 70 80 90 100 110 JUNCTION TEMPERATURE (C) RTC = OPEN TEMPCO = 50ppm/C RTC 1.9k RMOD = OPEN TEMPCO = 4000ppm/C
nodes are monitored for safety faults, and any node voltage that differs significantly from its expected value results in a fault (Table 1). When a fault condition is detected, the laser is shut down. See Applications Information for more information on laser safety. Shutdown The laser drivers offer dual redundant bias shutdown mechanisms. The SHDNDRV output drives an optional external MOSFET semiconductor. The bias and modulation drivers have separate, internal disable signals. Latched Fault Output Two complementary FAULT outputs are provided with the MAX3286/MAX3296 series. In the event of a fault, these outputs latch until one of three events occurs: 1) The power is switched off, then on. 2) EN is switched low, then high. 3) EN is switched to high, then low.
Power-On Reset (POR)
Figure 7 shows the power-on reset (POR) circuit for the MAX3286/MAX3296 series devices. A POR signal asserts low when VCC is in the operating range. The voltage operating range is determined by the LV pin, as shown in Table 2. POR contains an internal delay to reject noise on VCC during power-on or hot-plugging. The delay can be extended by adding capacitance to the PORDLY pin. The POR comparator includes hysteresis to improve noise rejection. The laser driver is shut down while VCC is out of the operating range.
Figure 5. Modulation Current vs. Temperature for Maximum and Minimum Temperature Coefficient
EN
(FROM POR CIRCUIT)
PULSE GENERATOR FLTDLY tFLTDLY Q RESET DOMINANT FAULT LATCH S 200ns DELAY R FAULT
VCC
FAULT DETECTION REF_FAULT MONITOR_FAULT MD_FAULT POLARITY_FAULT TC_FAULT MOD_FAULT
FAULT
EN SHDNDRV
ENABLE
MAX3286 MAX3296
Figure 6. Simplified Safety Circuit Schematic 10 ______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
PORDLY VCC MAX3286 MAX3296 28k 25k LV VARIABLE DELAY 36k 1.2V = 0.7s/F CPORDLY BANDGAP POR
0.018mW/mA at +70C. Using the above equation will produce a laser tempco of -3175ppm/C. To obtain the desired modulation current and tempco for the device, the following two equations can be used to determine the required values of RMOD and RTC: RTC = 0.21 - 250 Tempco (iMOD )
MAX3286-MAX3289/MAX3296-MAX3299
RMOD =
(RTC + 250)52 Tempco - 250 (0.19 - 48 Tempco)
Figure 7. Power-On Reset Circuit
Design Procedure
Select Laser
Select a communications-grade laser with a rise time of 260ps or better for 1.25Gbps, or 130ps or better for 2.5Gbps applications. To obtain the MAX3286/ MAX3296's AC specifications, the instantaneous output voltage at OUT+ must remain above VCC - 1V at all times. Select a high-efficiency laser that requires low modulation current and generates low-voltage swing at OUT+. Laser package inductance can be reduced by trimming the leads. Typical package leads have inductance of 25nH/in (1nH/mm), this inductance causes a larger voltage swing across the laser. A compensation filter network can also be used to reduce ringing, edge speed, and voltage swing.
where Tempco = -Laser Tempco. Figure 8a shows a family of curves derived from these equations. The straight diagonal lines depict constant tempcos. The curved lines represent constant modulation currents. If no temperature compensation is desired, Figure 8b displays a series of curves that show laser modulation current with respect to RMOD for different loads. The following useful equations were used to derive Figure 8a and the equations at the beginning of this section. The first assumes RL = 25. 1.15 1.06 + R + 250 R TC + 250 iMOD = 51 MOD -3 1 + 4.0 10 ( T - 25C)

[ A]
iMOD(70C) = iMOD(25C) + iMOD(25C) (TEMPCO)(70C-25C) A
[]
Programming the Modulation Current
Resistors at the MODSET and TC pins set the amplitude of the modulation current. The resistor RMOD sets the temperature-stable portion of the modulation current while the resistor R TC sets the temperatureincreasing portion of the modulation current. To determine the appropriate temperature coefficient from the slope efficiency () of the laser, use the following equation: Laser Tempco =
Programming the Bias Current/APC
Three application circuits are described below: common-cathode laser with photodiode, common-cathode laser without photodiode, and common-anode laser with photodiode. The POL and POL inputs determine the laser pinning (common cathode, common anode) and affect the smooth-start circuits (Table 4). Common Cathode with Photodiode (Optical Feedback) In the common-cathode with photodiode configuration, a servo control loop is formed by external PNP Q1, the laser diode, the monitor diode, RSET, and the powercontrol amplifier (Figure 9). The voltage at MD is stabilized to 1.7V. The monitor photodiode current (ID) is set by (VREF - VMD) / RSET = 0.95 / RSET. Determine the desired monitor current (ID), then select RSET = 0.95 / ID.
25 (70C - 25C)
70 - 25
10+6 [ppm / C]
where is the slope of the laser output power to the laser current. For example, suppose a laser has a slope efficiency 25 of 0.021mW/mA at +25C, which reduces to
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11
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
1000 500ppm 1000ppm 1500ppm RTC (k) 2000ppm 2500ppm 3000ppm 3500ppm 10 5mA 10mA 15mA 20mA 25mA RL = 25 1 1 10 RMOD (k) 100 1000 30mA
Figure 8a. RTC vs. RMOD for Various Conditions
The APC loop is compensated by CBIASDRV. A capacitor must be placed from BIASDRV to VCC to ensure lownoise operation and to reject power-supply noise. The time constant governs how quickly the laser bias current reacts to a change in the average total laser current (IBIASDRV + iMOD). A capacitance of 0.1F is sufficient to obtain a loop time constant in excess of 1s, provided that RDEG is chosen appropriately. Resistor RDEG may be necessary to ensure the APC loop's stability when low bias currents are desired. The voltage across RDEG should not be any larger than 250mV at maximum bias current. The discrete components used with the common cathode with photodiode configuration are as follows: RSET = 0.88 / ID CBIASDRV = 0.1F (typ)
40 LASER MODULATION CURRENT (iMOD) (mA) 35 30 25 20 15 10 5 0 0 2 4 6 8 RMOD (k) 10 12 14 10 LOAD NOTE: RTC = OPEN 25 LOAD 50 LOAD
Table 3. RTC and RMOD Selection Table
iMOD = 30mA TEMPCO (ppm/C) RMOD RTC (k) (k) 3500 3000 2500 2000 1500 1000 500 26.7 9.53 5.76 4.12 3.24 2.67 2.26 1.69 2.0 2.49 3.16 4.32 6.49 13.3 iMOD = 15mA RMOD (k) 53.6 18.7 11.3 8.06 6.19 5.11 4.22 RTC (k) 3.65 4.32 5.23 6.49 8.87 13.3 26.7 iMOD = 5mA RMOD (k) 162 57.6 34.8 24.9 19.1 15.8 13.3 RTC (k) 11.5 13.3 16.2 20.0 26.7 40.2 80.6
Figure 8b. Laser-Modulation Current vs. RMOD
Table 4. POL Pin Setup for Each Laser Configuration Type
DEVICE MAX3286/MAX3296 MAX3287/MAX3297 MAX3286/MAX3296 MAX3288/MAX3298 MAX3286/MAX3296 MAX3289/MAX3299 MAX3286/MAX3296 MAX3286/MAX3296 12 POL VCC -- VCC -- GND -- VCC GND POL GND -- GND -- VCC -- VCC GND Common anode with photodiode Not allowed; fault occurs Not allowed; fault occurs -- -- Common cathode without photodiode
VCC
DESCRIPTION Common cathode with photodiode
LASER PINNING
______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
RDEG = 0.25 / IBIAS(MAX) Q1 = general-purpose PNP, >100, ft > 5MHz B1 = ferrite bead (see Bias Filter section) M1 = general-purpose PMOS device (optional) CBIASDRV connected between BIASDRV and VCC is sufficient to obtain approximately a 1s APC loop time constant. This improves power-supply noise rejection. To select the external components: 1) Determine the required laser bias current: IBIAS = ITH + iMOD/2 2) Select RMD and RSET. Maxim recommends RSET = 1k, RMD = 5k, which results in VCC - VMON 250mV. 3) Select RMON where RMON = 250mV / IBIAS, assuming RSET = 1k and RMD = 5k.
VCC VCC
MAX3286-MAX3289/MAX3296-MAX3299
Common Cathode with Current Feedback
In the common-cathode configuration with current feedback, a servo control loop is formed by an external PNP transistor (Q1), RMON, the controlled-reference voltage block, R SET , R MD , and the power-control amplifier (Figure 10). The voltage at MD is stabilized to 1.7V. The voltage at MON is set by the resistors RSET and RMD. As in the short-wavelength configuration, a 0.1F
MAX3286 MAX3287 MAX3296 MAX3297
RDEG REF VCC MAX3286/96 ONLY POL POL MD CONTROLLED REFERENCE VOLTAGE VREF = 2.65V SMOOTH START MON SHDNDRV 1.7V BIASDRV ID POWER CONTROL AMPLIFIER FERRITE BEAD B1 Q1 VCC CBIASDRV M1
RSET
IBIAS
PHOTO DIODE
LASER
Figure 9. Common-Cathode Laser with Photodiode
VCC
VCC
MAX3286 MAX3288 MAX3296 MAX3298
RSET
RMON REF VCC MAX3286/96 POL ONLY POL ID RMD MD CONTROLLED REFERENCE VOLTAGE VREF = 2.65V - 2.25V (VCC - VMON) SMOOTH START MON SHDNDRV 1.7V BIASDRV POWER CONTROL AMPLIFIER FERRITE BEAD B1 Q1 M1 CBIASDRV
IBIAS
LASER
Figure 10. Common Cathode with Current Feedback (PNP Configuration) ______________________________________________________________________________________ 13
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
The relationship between laser bias current and RMON is shown in Figure 11. The remaining discrete components used with the common-cathode without photodiode configuration are as follows: Q1 = general-purpose PNP, >100, ft > 5MHz B1 = ferrite bead (see Bias Filter section) M1 = general-purpose PMOS device (optional) CBIASDRV = 0.1F (typ) Common Anode with Photodiode In the common-anode configuration with photodiode, a servo control loop is formed by an external NPN transistor (Q1), the laser diode, the monitor diode, RSET, and the power-control amplifier. The voltage at MD is stabilized to 1.7V. The monitor photodiode current is set by ID = VMD / RSET (Figure 12). Determine the desired monitor current (ID), then select RSET = 1.7V / ID.
100 RSET = 1k RMD = 5k LASER BIAS CURRENT (mA) 10
CBIASDRV and a degeneration resistor (RDEG) must be connected to the bias transistor (in this case NPN) to obtain the desired APC loop time constant. This improves power-supply (and ground) noise rejection. A capacitance of 0.1F is sufficient to obtain time constants of up to 5s in most cases. The voltage across RDEG should not be larger than 250mV at maximum bias current. The discrete components used with the common-anode with photodiode configuration are summarized as follows: RSET = 1.7 / ID CBIASDRV = 0.1F (typ) RDEG = 0.25 / IBIAS(MAX) Q1 = general-purpose NPN, > 100, ft > 5MHz B1 = ferrite bead (see Bias Filter section) M1 = general-purpose PMOS (optional)
Programming POR Delay
A capacitor may be added to PORDLY to increase the delay for which POR will be asserted low (meaning that VCC is within the operational range) when powering up the part. The delay will be approximately: t= CPORDLY
1
(1.4)10-6
[s]
See Typical Operating Characteristics.
0.1 10 100 RMON () 1k 10k
Figure 11. Common Cathode Without Photodiode Laser
VCC
MAX3286 MAX3289 MAX3296 MAX3299
VCC VCC MONITOR DIODE VCC MAX3286/96 POL ONLY SMOOTH START 1.7V BIASDRV POWER CONTROL AMPLIFIER IBIAS RDEG Q1 CBIASDRV MON SHDNDRV FERRITE BEAD B1 LASER
POL MD
RSET
ID
Figure 12. Common Anode With Photodiode 14 ______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
Designing the Bias Filter and Output Pull-Up Beads
To reduce deterministic jitter, add a ferrite-bead inductor between the collector of the biasing transistor and either the anode or cathode of the laser, depending on type (see Typical Operating Characteristics). Use a ferrite-bead inductor with an impedance >100 between = 10MHz and = 2GHz, and a DC resistance < 3. Maxim recommends the Murata BLM11HA102SG. These inductors are also desirable for tying the OUT+ and OUT- pins to VCC.
MAX3286-MAX3289/MAX3296-MAX3299
UNCOMPENSATED
CORRECTLY COMPENSATED POWER
OVERCOMPENSATED
Designing the Laser-Compensation Filter Network
Laser package inductance causes the laser impedance to increase at high frequencies, leading to ringing, overshoot, and degradation of the output eye pattern. A lasercompensation filter network can be used to reduce the output load seen by the laser driver at high frequencies, thereby reducing output ringing and overshoot. The compensation components (RCOMP and CCOMP) are most easily determined by experimentation. Begin with RCOMP = 25 and CCOMP = 2pF. Increase CCOMP until the desired transmitter eye is obtained (Figure 13).
TIME
Figure 13. Laser Compensation
into the body, for applications intended to support or sustain life, or for any other application where the failure of a Maxim product could create a situation where personal injury or death may occur.
Layout Considerations
The MAX3286/MAX3296 series are high-frequency products. Their performance largely depends upon the circuit board layout. Use a multilayer circuit board with a dedicated ground plane. Use short laser package leads placed close to the modulator outputs. Power supplies must be capacitively bypassed to the ground plane with surface-mount capacitors placed near the power-supply pins. The dominant pole of the APC circuit is normally located at BIASDRV. To prevent a second pole in the APC (that can lead to oscillations), ensure that parasitic capacitance at MD is minimized.
Quick Shutdown
To reduce laser shutdown time, a FET device can be attached to SHDNDRV as shown in Figure 10. This will provide a typical laser power shutdown time of less than 10s.
Applications Information
Laser Safety and IEC 825
The International Electrotechnical Commission (IEC) determines standards for hazardous light emissions from fiber optic transmitters. IEC 825 defines the maximum light output for various hazard levels. The MAX3286/ MAX3296 series provide features that facilitate compliance with IEC 825. A common safety requirement is single-point fault tolerance, whereby one unplanned short, open, or resistive connection does not cause excess light output. When these laser drivers are used as shown in the Typical Operating Circuits, the circuits respond to faults as shown in Table 5. Using these laser drivers alone does not ensure that a transmitter design is compliant with IEC 825. The entire transmitter circuit and component selections must be considered. Customers must determine the level of fault tolerance required by their applications, recognizing that Maxim products are not designed or authorized for use as components in systems intended for surgical implant
Common Questions
Laser output is ringing or contains overshoot. This is often caused by inductive laser packaging. Try reducing the length of the laser leads. Modify the compensation components to reduce the driver's output edge speed (see Design Procedure). Extreme ringing can be caused by low voltage at the OUT pins. This may indicate that pullup beads or a lower modulation current are needed. Low-frequency oscillation on the laser output. This is more prevalent at low temperatures. The APC may be oscillating. Try increasing the value of CBIASDRV or increasing the value of RDEG. Ensure that the parasitic capacitance at the MD node is kept very small (<10pF). The APC is not needed. Connect FLTDLY to ground to disable fault detection. Connect MD to REF and MON to VCC. BIASDRV and SHDNDRV can be left open.
______________________________________________________________________________________
15
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
Table 5. Circuit Response to Various Single-Point Faults
PIN NAME CIRCUIT RESPONSE TO OVERVOLTAGE OR SHORT TO VCC CIRCUIT RESPONSE TO UNDERVOLTAGE OR SHORT TO GROUND
MAX3286/MAX3296 ONLY FAULT FAULT POR PORDLY EN EN LV POL POL MON (Also MAX3288/98) SHDNDRV (Also MAX3287/97/ 89/99) ALL DEVICES FLTDLY IN+, INREF MD Any fault that occurs cannot be reset. Does not affect laser power. Does not affect laser power. Fault state* occurs. Fault state* occurs. In common cathode configurations, the laser bias current is shut off. In common anode, high laser power triggers a fault state*. Shutdown occurs if a shutdown FET (M1) is used. If shutdown FET is not used, other means must be used to prevent high laser power. Does not affect laser power. Does not affect laser power. Does not affect laser power. Does not affect laser power. Does not affect laser power. In common cathode configurations, a fault state* occurs; otherwise, does not affect laser power. A fault state* occurs. In common anode configurations, the laser bias current is shut off. In common cathode, high laser power triggers a fault state*. Shutdown occurs if a shutdown FET (M1) is used (Figures 9,10). Does not affect laser power. Fault state* occurs. Fault state* occurs. Does not affect laser power. Does not affect laser power. Does not affect laser power. Does not affect laser power. Normal condition for circuit operation. Fault state* occurs. Does not affect laser power. If POL is a TTL HIGH, a fault state* occurs; otherwise, the circuit is in normal operation. If POL is a TTL HIGH, a fault state* occurs; otherwise, the circuit is in normal operation. In common-cathode without photodiode configuration, a fault state* occurs; otherwise, does not affect laser power. Does not affect laser power. If optional FET is used, the laser output is shut off. Does not affect laser power. Does not affect laser power. Does not affect laser power. Fault state* occurs. Fault state* occurs. Normal condition for circuit operation. Fault state* occurs if VCC is less than +4.5V. If POL is a TTL LOW, a fault state* occurs; otherwise, the circuit is in normal operation. If POL is a TTL LOW, a fault state* occurs; otherwise, the circuit is in normal operation. A fault state* occurs.
Does not affect laser power.
BIASDRV
OUT+, OUTMODSET TC
* A fault state will assert the FAULT pins, disable the modulator outputs, disable the bias output, and assert the SHDNDRV pin.
16
______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
The modulator is not needed. Leave TC and MODSET open. Connect IN+ to VCC. IN- to REF, and leave OUT+ and OUT- open. Wirebonding Die The MAX3286/MAX3296 series use bondpads with gold metalization. Make connections to the die with gold wire only, using ball-bonding techniques. Wedge bonding is not recommended. Bondpad size is 4mil square. Die thickness is typically 15mils (0.38mm).
Interface Models
Figures 14-18 show typical input/output models for the MAX3286/MAX3296 series of laser drivers. If dice are used, replace the package parasitic elements with bondwire parasitic elements.
MAX3286-MAX3289/MAX3296-MAX3299
MAX3286 MAX3296 4k 2.5k
VCC
MAX3286 MAX3296 10k 550 FAULT, FAULT, POR
VCC
60 SHDNDRV
Figure 14. Logic Outputs
Figure 15. SHDNDRV Output
VCC PACKAGE 50
VCC PACKAGE 50
1.5nH 0.2pF
OUT1pF
OUT+
1.5nH 0.2pF
1pF
Figure 16. Modulator Outputs
______________________________________________________________________________________
17
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
PACKAGE
MAX3286 MAX3296 VCC
VCC
1.5nH 0.2pF
IN+ Q1 1pF 400 VCC
1.5nH 0.2pF
IN1pF
400 Q2
INPUT COMMON MODE VOLTAGE VCC - 0.3V RIN Q1, Q2 > 100k
Figure 17. Data Inputs
VCC MAX3286 MAX3296 40
BIASDRV
40
Figure 18. BIASDRV Output 18 ______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
Selector Guide
DATA RATE/DEVICE LASER CONFIGURATION COMMON ANODE WITH PHOTODIODE Longwave MAX3286 MAX3287 MAX3288 MAX3289 MAX3296 MAX3297 MAX3298 MAX3299 COMMON CATHODE WITH PHOTODIODE Shortwave or VCSEL COMMON CATHODE WITHOUT PHOTODIODE VCSEL 32 TQFP/Dice 16 TSSOP-EP 16 TSSOP-EP 16 TSSOP-EP
MAX3286-MAX3289/MAX3296-MAX3299
1.25Gbps
2.5Gbps
PACKAGE
Pin Configurations (continued)
OUT+
TOP VIEW
TC
MODSET
OUT-
GND
VCC
VCC 26
32 FAULT N.C. FAULT POR GND EN EN PORDLY 1 2 3 4 5 6 7 8 9 FLTDLY
31
30
29
28
27
VCC 25 24 BIASDRV 23 SHDNDRV 22 GND 21 MON GND 1 FLTDLY 2 VCC 3 IN+ 4 IN- 5 GND 6 REF 7 MD 8 16 TC 15 MODSET 14 VCC
MAX3286 MAX3296
MAX3288 MAX3298
13 OUT12 OUT+ 11 VCC 10 BIASDRV 9 MON
20 MD 19 I.C. 18 POL 17 POL
TSSOP-EP*
10 LV 11 VCC 12 IN+ 13 IN14 GND 15 REF 16 N.C.
*Exposed paddle is connected to GND.
TQFP
Ordering Information (continued)
PART MAX3287CUE MAX3288CUE MAX3289CUE MAX3296CHJ MAX3296C/D MAX3297CUE MAX3298CUE TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C 0C to +70C 0C to +70C 0C to +70C 0C to +70C PIN-PACKAGE 16 TSSOP-EP** 16 TSSOP-EP** 16 TSSOP-EP** 32 TQFP (5mm x 5mm) Dice* 16 TSSOP-EP** 16 TSSOP-EP**
MAX3299CUE 0C to +70C 16 TSSOP-EP** *Dice are designed to operate from TJ = 0C to +110C, but are tested and guaranteed only at TA = +25C. **Exposed paddle ______________________________________________________________________________________ 19
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
Typical Application Circuits
+3.0V TO +5.5V
MAX3286/MAX3296 COMMON-CATHODE LASER WITH PHOTODIODE
0.01F
0.01F 0.01F FLTDLY MON POL EN VCC SHDNDRV CBIASDRV 0.1F BIASDRV VCC
PMOSFET (OPTIONAL) PNP TRANSISTOR
PORDLY 0.01F IN+ DATA INPUT 115 IN0.01F POR FAULT
FERRITE BEAD
MAX3286 MAX3296
0.01F OUT+ OUT0.01F CCOMP RCOMP
25 FAULT LV POL EN GND TC MODSET RMOD RSET REF MD VCC
RTC
+3.0V TO +5.5V 0.01F
MAX3286/MAX3296 COMMON-CATHODE LASER WITHOUT PHOTODIODE
0.01F
0.01F FLTDLY PORDLY 0.01F IN+
RMON
POL
EN
VCC
MON
CBIASDRV 0.1F VCC
BIASDRV
PNP TRANSISTOR
DATA INPUT 115 INSHDNDRV POR FAULT FAULT LV POL EN GND
FERRITE BEAD
MAX3286 MAX3296
0.01F OUT+ OUT0.01F CCOMP 25 VCC RCOMP
0.01F
TC
MODSET RMOD
REF MD RMD 5k RSET 1k
RTC
20
______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
Typical Application Circuits (continued)
+3.0V TO +5.5V
MAX3286-MAX3289/MAX3296-MAX3299
MAX3286/MAX3296 COMMON-ANODE LASER WITH PHOTODIODE
0.01F
0.01F FLTDLY
MON
POL
EN
VCC
0.01F VCC
PORDLY 0.01F IN+ 0.01F OUT0.01F CCOMP RCOMP 18 FERRITE BEAD
DATA INPUT 115 IN0.01F POR FAULT FAULT LV SHDNDRV POL EN GND
MAX3286 MAX3296
OUT+
25
VCC BIASDRV CBIASDRV 0.1F
NPN TRANSISTOR
MD TC MODSET REF RDEG RTC RMOD RSET
+3.0V TO +5.5V 0.01F VCC CBIASDRV 0.1F BIASDRV IN+ DATA INPUT 115 IN0.01F 0.01F FLTDLY SHDNDRV GND TC RTC MODSET RMOD RSET REF MD VCC VCC RDEG
MAX3287/MAX3297 COMMON-CATHODE LASER WITH PHOTODIODE
0.01F
PNP TRANSISTOR
FERRITE BEAD
MAX3287 MAX3297
0.01F OUT+ OUT0.01F CCOMP
25
RCOMP
______________________________________________________________________________________
21
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
Typical Application Circuits (continued)
+3.0V TO +5.5V 0.01F
MAX3288/MAX3298 COMMON-CATHODE LASER WITHOUT PHOTODIODE
0.01F IN+ DATA INPUT 115 IN0.01F 0.01F FLTDLY
RMON
VCC
MON
CBIASDRV 0.1F VCC
BIASDRV
PNP TRANSISTOR
FERRITE BEAD
MAX3288 MAX3298
0.01F OUT+ OUTCCOMP 0.01F 25 RCOMP
GND
TC RTC
MODSET RMOD
REF MD
VCC RMD 5k RSET 1k
+3.0V TO +5.5V
MAX3289/MAX3299 COMMON-ANODE LASER WITH PHOTODIODE
0.01F IN+ DATA INPUT 115 IN0.01F
VCC
0.01F VCC
0.01F OUT0.01F CCOMP RCOMP
18 FERRITE BEAD
MAX3289 MAX3299
OUT+
25
0.01F FLTDLY BIASDRV SHDNDRV GND TC RTC MODSET RMOD REF MD
VCC NPN TRANSISTOR
CBIASDRV 0.1F
RDEG RSET
22
______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
Chip Topographies
MAX3286
PORDLY PORDLY FAULT FAULT GND POR
MAX3286-MAX3289/MAX3296-MAX3299
MAX3296
FAULT FAULT TC MODSET
HF34Z
GND
EN
FLTDLY LV
HF34Z-1Z
TC MODSET VCC OUTOUT+ VCC VCC
FLTDLY LV VCC IN+ INGND REF
VCC IN+ INGND REF
EN
POR
EN
EN
0.072" (1.829mm)
VCC OUTOUT+ VCC VCC
0.072" (1.829mm)
MON
GND
I.C.
MON
SHDNDRV
BIASDRV
GND
MD
POL
MD
SHDNDRV
POL
POL
I.C.
0.053" (1.346mm)
0.053" (1.346mm)
TRANSISTOR COUNT: 1154 SUBSTRATE CONNECTED TO GND
TRANSISTOR COUNT: 1154 SUBSTRATE CONNECTED TO GND
______________________________________________________________________________________
BIASDRV
POL
23
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
Package Information
32L,TQFP.EPS
24
______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers
Package Information (continued)
TSSOP.EPS
MAX3286-MAX3289/MAX3296-MAX3299
______________________________________________________________________________________
25
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
NOTES
26
______________________________________________________________________________________
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
NOTES
______________________________________________________________________________________
27
3.0V to 5.5V, 1.25Gbps/2.5Gbps LAN Laser Drivers MAX3286-MAX3289/MAX3296-MAX3299
NOTES
Maxim makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Maxim assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability, including without limitation consequential or incidental damages. "Typical" parameters can and do vary in different applications. All operating parameters, including "typicals" must be validated for each customer application by customer's technical experts. Maxim products are not designed, intended or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Maxim product could create a situation where personal injury or death may occur.
28 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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