MAX3646ETG+T Fast Delivery |IC PHOENIX CO.,LIMITED

MAX3646ETG+T ,155Mbps to 622Mbps SFF/SFP Laser Driver with Extinction Ratio Controlfeaturesof automatic power control (APC), modulation compensa- ♦ Automatic Power Control (APC)tion, ..
MAX364CPE ,Precision, Quad, SPST Analog SwitchesELECTRICAL CHARACTERISTICS—Dual Supplies(V+ = 15V, V- = -15V, VL = 5V, GND = 0V, V = 2.4V, V = 0.8V ..
MAX364CPE ,Precision, Quad, SPST Analog SwitchesApplicationsMAX365CPE 0°C to +70°C 16 Plastic DIPSample-and-Hold Circuits Communication SystemsMAX3 ..
MAX364CSE ,Precision, Quad, SPST Analog SwitchesMAX364/MAX36519-0181; Rev 0; 9/93Precision, Quad, SPST Analog Switches_______________
MAX364CSE ,Precision, Quad, SPST Analog SwitchesFeaturesThe MAX364/MAX365 are precision, quad, single-pole ' Low On Resistance: < 45Ω Typical (85Ω ..
MAX364CSE+ ,Precision, Quad, SPST Analog SwitchesApplicationsMAX364ESE -40°C to +85°C 16 Narrow SOSample-and-Hold Circuits Communication SystemsMAX3 ..
MAX7301AAX+ ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port I/O ExpanderApplications MAX7301 P10 I/O 1035 11CHIP SELECT P11 I/O 11CS● White Goods33 6CLOCK IN SCLK P12I/O 1 ..
MAX7301AAX+ ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port I/O ExpanderGeneral Description Beneits and
MAX7301AAX+T ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port I/O ExpanderElectrical Characteristics(Typical Operating Circuit, V+ = 2.5V to 5.5V, T = T to T , unless otherw ..
MAX7301AAX-T ,4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port I/O ExpanderElectrical Characteristics(Typical Operating Circuit, V+ = 2.5V to 5.5V, T = T to T , unless otherw ..
MAX7301ATL , 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port I/O Expander
MAX7301ATL , 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port I/O Expander

MAX3646ETG+T
155Mbps to 622Mbps SFF/SFP Laser Driver with Extinction Ratio Control
General Description
The MAX3646 is a +3.3V laser driver designed for mul-
tirate transceiver modules with data rates from
155Mbps to 622Mbps. Lasers can be DC-coupled to
the MAX3646 for reduced component count and ease
of multirate operation.
Laser extinction ratio control (ERC) combines the features
of automatic power control (APC), modulation compensa-
tion, and built-in thermal compensation. The APC loop
maintains constant average optical power. Modulation
compensation increases the modulation current in pro-
portion to the bias current. These control loops, com-
bined with thermal compensation, maintain a constant
optical extinction ratio over temperature and lifetime.
The MAX3646 accepts differential data input signals.
The wide 5mA to 60mA (up to 85mA AC-coupled) mod-
ulation current range and up to 100mA bias current
range, make the MAX3646 ideal for driving FP/DFB
lasers in fiber optic modules. External resistors set the
required laser current levels. The MAX3646 provides
transmit disable control (TX_DISABLE), single-point
fault tolerance, bias-current monitoring, and photocur-
rent monitoring. The device also offers a latched failure
output (TX_FAULT) to indicate faults, such as when the
APC loop is no longer able to maintain the average
optical power at the required level. The MAX3646 is
compliant with the SFF-8472 transmitter diagnostic and
SFP MSA timing requirements.
The MAX3646 is offered in a 4mm x 4mm, 24-pin thin
QFN package and operates over the extended -40°C to
+85°C temperature range.
Applications
Multirate OC-3 to OC-12 FEC Transceivers
125Mbps Ethernet SFP, GBIC, and 1 x 9
Transceivers
FeaturesSingle +3.3V Power Supply47mA Power-Supply Current85mA Modulation Current100mA Bias CurrentAutomatic Power Control (APC)Modulation CompensationOn-Chip Temperature CompensationSelf-Biased Inputs for AC-CouplingGround-Referenced Current MonitorsLaser Shutdown and Alarm OutputsEnable Control and Laser Safety Feature
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
Ordering Information
19-3161; Rev 2; 6/11
EVALUATION KIT
AVAILABLE
BIAS
APCFIL
VCC
VCC
TX_DISABLE
MODTCOMP
TH_TEMP
OUT+
APCFIL
SHUTDOWN
GND
BC_MON
TX_F
AUL
GND
VCC
VCC
MODSETAPCSET891011122322212019
TOP VIEW
*THE EXPOSED PADDLE MUST BE SOLDERED TO SUPPLY
GROUND ON THE CIRCUIT BOARD.
IN+
IN-
PC_MON
OUT-
MODBCOMP
MAX3646
*EP
Pin Configuration
Typical Application Circuit appears at end of data sheet.
+Denotes a lead-free/RoHS-compliant package.
*EP = Exposed pad.
T = Tape and reel.
PART TEMP RANGE PIN-PACKAGE
MAX3646ETG -40°C to +85°C 24 Thin QFN-EP*
MAX3646ETG-T -40°C to +85°C 24 Thin QFN-EP*
MAX3646ETG+ -40°C to +85°C 24 Thin QFN-EP*
MAX3646ETG+T -40°C to +85°C 24 Thin QFN-EP*
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +2.97V to +3.63V, TA= -40°C to +85°C. Typical values are at VCC= +3.3V, IBIAS= 60mA, IMOD= 60mA, TA= +25°C, unless
otherwise noted.) (Notes 1, 2)
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.
Supply Voltage VCC...............................................-0.5V to +6.0V
IN+, IN-, TX_DISABLE, TX_FAULT, SHUTDOWN,
BC_MON, PC_MON, APCFILT1, APCFILT2,
MD, TH_TEMP, MODTCOMP, MODBCOMP,
MODSET, and APCSET Voltage.............-0.5V to (VCC+ 0.5V)
OUT+, OUT-, BIAS Current.............................-20mA to +150mA
Continuous Power Dissipation (TA= +70°C)
24-Pin TQFN (derate 27.8mW/°C above +70°C).......2222mW
Operating Junction Temperature Range...........-55°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Soldering Temperature (reflow)
Lead (Pb)-free packages..............................................+260°C
Packages containing lead (Pb).....................................+240°C
Storage Temperature Range.............................-55°C to +150°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
POWER SUPPLY
Supply CurrentICC(Note 3)4760mA
Power-Supply Noise RejectionPSNRf ≤ 1MHz, 100mAP-P (Note 4)33dB
I/O SPECIFICATIONS
Differential Input SwingVIDDC-coupled, Figure 10.22.4VP-P
Common-Mode InputVCM1.7VCC -
VID / 4V
LASER BIAS
Bias-Current-Setting Range1100mA
Bias Off CurrentTX_DISABLE = high0.1mA
Bias-Current Monitor RatioIBIAS / IBC_MON627690mA/mA
LASER MODULATION
Modulation Current-Setting
RangeIMOD(Note 5)585mA
Output Edge Speed20% to 80%
(Notes 6, 7)5mA ≤ IMOD ≤ 85mA100200ps
Output Overshoot/Undershoot(Note 7)±6%
Random Jitter(Notes 6, 7)1.12.5psRMS
622Mbps, 5mA ≤ IMOD ≤ 85mA2446Deterministic Jitter (Notes 6, 8)155Mbps, 5mA ≤ IMOD ≤ 85mA45100psP-P
5mA ≤ IMOD ≤ 10mA±175±600Modulation-Current Temperature
Stability(Note 6)10mA < IMOD ≤ 85mA±125±480ppm/°C
5mA ≤ IMOD ≤ 10mA±20Modulation-Current-Setting Error15Ω load,
TA = +25°C10mA < IMOD ≤ 85mA±15%
Modulation Off CurrentTX_DISABLE = high0.1mA
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
Note 1:AC characterization is performed using the circuit in Figure 2 using a PRBS 223- 1 or equivalent pattern.
Note 2:Specifications at -40°C are guaranteed by design and characterization.
Note 3:Excluding IBIASand IMOD. Input data is AC-coupled. TX_FAULT open, SHUTDOWN open.
Note 4:Power-supply noise rejection (PSNR) = 20log10(Vnoise (on VCC) / ΔVOUT). VOUTis the voltage across the 15Ωload when IN+
is high.
Note 5:The minimum required voltage at the OUT+ and OUT- pins is +0.75V.
Note 6:Guaranteed by design and characterization.
Note 7:Tested with 00001111 pattern at 622Mbps.
Note 8:DJ includes pulse-width distortion (PWD).
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
AUTOMATIC POWER AND EXTINCTION RATIO CONTROLS
Monitor-Diode Input Current
RangeIMDAverage current into the MD pin181500µA
MD Pin Voltage1.4V
MD Current Monitor RatioIMD / IPC_MON0.850.931.15mA/mA
APC Loop Time ConstantCAPC_FILT = 0.01µF, ΔIMD / ΔIBIAS = 1/703.3µs
APC Setting Stability(Note 6)±100±480ppm/°C
APC Setting AccuracyTA = +25°C±15%
IMOD Compensation-Setting
Range by BiasKK = ΔIMOD / ΔIBIAS01.5mA/mA
IMOD Compensation-Setting
Range by TemperatureTCTC = ΔIMOD / ΔT (Note 6)01.0mA/°C
Threshold-Setting Range for
Temperature CompensationTTH(Note 6)+10+60°C
LASER SAFETY AND CONTROL
Bias and Modulation Turn-Off
Delay
CAPC_FILT = 0.01µF, ΔIMD / ΔIBIAS = 1/80
(Note 6)5µs
Bias and Modulation Turn-On
Delay
CAPC_FILT = 0.01µF, ΔIMD / ΔIBIAS = 1/80
(Note 6)600µs
Threshold Voltage at Monitor PinsVREFFigure 51.141.31.39V
INTERFACE SIGNALS
TX_DISABLE Input HighVHI2.0V
TX_DISABLE Input LowVLORPULL = 45kΩ (typical)0.8V
VHI = VCC15TX_DISABLE Input CurrentVLO = GND-70-140µA
TX_FAULT Output LowSinking 1mA, open collector0.4V
Shutdown Output HighSourcing 100µAVCC - 0.4V
Shutdown Output LowSinking 100µA0.4V
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +2.97V to +3.63V, TA= -40°C to +85°C. Typical values are at VCC= +3.3V, IBIAS= 60mA, IMOD= 60mA, TA= +25°C, unless
otherwise noted.) (Notes 1, 2)
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
Typical Operating Characteristics
(VCC= +3.3V, CAPC= 0.01µF, IBIAS= 20mA, IMOD= 30mA, TA= +25°C, unless otherwise noted.)
OPTICAL EYE DIAGRAM
(622.08Mbps, 27 - 1 PRBS, 467MHz FILTER)
MAX3646 toc01
270ps/div
1310nm FP LASER
re = 8.2dB
OPTICAL EYE DIAGRAM
(155Mbps, 27 - 1 PRBS, 117MHz FILTER)
MAX3646 toc02
1ns/div
1310nm FP LASER
re = 8.2dB
ELECTRICAL EYE DIAGRAM
(IMOD = 30mA, 622.08MHz, 27 - 1 PRBS)
MAX3646 toc03
320ps/div
75mV/div
2pF BETWEEN OUT+
AND OUT-
SUPPLY CURRENT (ICC) vs. TEMPERATURE
(EXCLUDES BIAS AND MODULATION CURRENTS)
MAX3646 toc04
TEMPERATURE (°C)
SUPPLY CURRENT (mA)706050403020100-10-20-30
3.63V
2.97V
3.3V
BIAS-CURRENT MONITOR RATIO
vs. TEMPERATURE
MAX3646 toc05
TEMPERATURE (°C)
IBIAS
BC_MON
(mA/mA)705060-10010203040-30-20
PHOTOCURRENT MONITOR RATIO
vs. TEMPERATURE
MAX3646 toc06
TEMPERATURE (°C)
IMD
PC_MON
(mA/mA)705060-10010203040-30-20
MODULATION CURRENT vs. RMODSET
MAX3646 toc07
RMODSET (kΩ)
MOD
(mA)100
PHOTODIODE CURRENT vs. RAPCSET
MAX3646 toc08
RAPCSET (kΩ)
IMD
(mA)1
DETERMINISTIC JITTER vs.
MODULATION CURRENT
MAX3646 toc09
IMOD (mA)
DJ (ps
P-P70506020304010
155mbps
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
Typical Operating Characteristics (continued)
(VCC= +3.3V, CAPC= 0.01µF, IBIAS= 20mA, IMOD= 30mA, TA= +25°C, unless otherwise noted.)
RANDOM JITTER vs.
MODULATION CURRENT
MAX3646 toc10
IMOD (mA)
RJ (ps
RMS70506020304010
COMPENSATION (K) vs. RMODBCOMP
MAX3646 toc11
RMODBCOMP (kΩ)
K (mA/mA)10.10.01
TEMPERATURE COMPENSATION vs.
RTH_TEMP (RMODTCOMP = 500Ω)
MAX3646 toc12
TEMPERATURE (°C)
IMOD
(mA)706050403020100
RTH_TEMP = 12kΩ
RTH_TEMP = 7kΩ
RTH_TEMP = 4kΩ
RTH_TEMP = 2kΩ
TEMPERATURE COMPENSATION vs.
RTH_TEMP (RMODTCOMP = 10kΩ)
MAX3646 toc13
TEMPERATURE (°C)
MOD
(mA)706050403020100
RTH_TEMP = 12kΩ
RTH_TEMP = 7kΩ
RTH_TEMP = 4kΩ
RTH_TEMP = 2kΩ
HOT PLUG WITH TX_DISABLE LOW
MAX3646 toc14
20ms/div
VCC
FAULT
TX_DISABLE
LASER
OUTPUT
3.3V
t_init = 59.6ms
LOW
LOW
TRANSMITTER ENABLE
MAX3646 toc15
10μs/div
VCC
FAULT
TX_DISABLE
LASER
OUTPUT
3.3V
t_on = 23.8μs
LOW
HIGH
LOW
TRANSMITTER DISABLE
MAX37646 toc16
20ns/div
VCC
FAULT
TX_DISABLE
LASER
OUTPUT
3.3V
91.2ns
LOW
HIGH
LOW
RESPONSE TO FAULT
MAX3646 toc17
400ns/div
VPC_MON
FAULT
TX_DISABLE
LASER
OUTPUT
t_fault = 160ns
EXTERNALLY
FORCED FAULT
FAULT RECOVERY TIME
MAX3646 toc18
40ms/div
VPC_MON
FAULT
TX_DISABLE
LASER
OUTPUT
t_init = 58ms
EXTERNALLY
FORCED FAULT
LOW
LOWLOW
HIGH
HIGH
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
PIN NAME FUNCTION
1 MODTCOMP
Modulation-Current Compensation from Temperature. A resistor at this pin sets the temperature
coefficient of the modulation current when above the threshold temperature. Leave open for zero
temperature compensation.
2, 5, 14, 17 VCC +3.3V Supply Voltage IN+ Noninverted Data Input
4 IN- Inverted Data Input
6 TX_DISABLE Transmitter Disable, TTL. Laser output is disabled when TX_DISABLE is asserted high or left
unconnected. The laser output is enabled when this pin is asserted low.
7 PC_MON Photodiode-Current Monitor Output. Current out of this pin develops a ground-referenced voltage
across an external resistor that is proportional to the monitor diode current.
8 BC_MON Bias-Current Monitor Output. Current out of this pin develops a ground-referenced voltage across
an external resistor that is proportional to the bias current.
9 SHUTDOWN Shutdown Driver Output. Voltage output to control an external transistor for optional shutdown
circuitry.
10, 12 GND Ground
11 TX_FAULT Open-Collector Transmit Fault Indicator (Table 1)
13 BIAS Laser Bias-Current Output
15 OUT- Inverted Modulation-Current Output. IMOD flows into this pin when input data is low.
16 OUT+ Noninverted Modulation-Current Output. IMOD flows into this pin when input data is high.
18 MD Monitor Photodiode Input. Connect this pin to the anode of a monitor photodiode. A capacitor to
ground is required to filter the high-speed AC monitor photocurrent.
19 APCFILT1 Connect a capacitor (CAPC) between pin 19 (APCFILT1) and pin 20 (APCFILT2) to set the dominant
pole of the APC feedback loop.
20 APCFILT2 (See Pin 19)
21 APCSET
A resistor connected from this pin to ground sets the desired average optical power. The total
capacitive load at the APCSET pin should be no more than 10pF. Minimize metal resistance for
ground connections.
22 MODSET
A resistor connected from this pin to ground sets the desired constant portion of the modulation
current. The total capacitive load at the MODSET pin should be no more than 10pF. Minimize
metal resistance for ground connections.
23 MODBCOMP Modulation-Current Compensation from Bias. Couples the bias current to the modulation current.
Mirrors IBIAS through an external resistor. Leave open for zero-coupling.
24 TH_TEMP Threshold for Temperature Compensation. A resistor at this pin programs the temperature above
which compensation is added to the modulation current.
— EP Exposed Pad. Solder the exposed pad to the circuit board ground for specified thermal and
electrical performance.
Pin Description
Detailed Description
The MAX3646 laser driver consists of three main parts:
a high-speed modulation driver, biasing block with
ERC, and safety circuitry. The circuit design is opti-
mized for high-speed, low-voltage (+3.3V) operation
(Figure 4).
High-Speed Modulation Driver
The output stage is composed of a high-speed differ-
ential pair and a programmable modulation current
source. The MAX3646 is optimized for driving a 15Ω
load. The minimum instantaneous voltage required at
OUT- is 0.7V for modulation currents up to 60mA and
0.75V for currents from 60mA to 85mA. Operation
above 60mA can be accomplished by AC-coupling or
with sufficient voltage at the laser to meet the driver
output voltage requirement.
To interface with the laser diode, a damping resistor
(RD) is required. The combined resistance damping
resistor and the equivalent series resistance (ESR) of
the laser diode should equal 15Ω. To further damp
aberrations caused by laser diode parasitic induc-
tance, an RC shunt network may be necessary. Refer to
Application Note 274: HFAN-02.0: Interfacing Maxim
Laser Drivers with Laser Diodes for more information.
Any capacitive load at the cathode of a laser diode
degrades optical output performance. Because the
BIAS output is directly connected to the laser cathode,
minimize the parasitic capacitance associated with the
pin by using an inductor to isolate the BIAS pin para-
sitics form the laser cathode.
Extinction Ratio Control
The extinction ratio (re) is the laser on-state power
divided by the off-state power. Extinction ratio remains
constant if peak-to-peak and average power are held
constant:= (2PAVG+ PP-P) / (2PAVG- PP-P)
MAX3646
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
VIN+
VIN-
200mV (min)
2400mV (max)
100mV (min)
1200mV (max)
IMOD
VOLTAGE
CURRENT
TIME
SINGLE ENDED
DIFFERENTIAL(VIN+) - (VIN-)
IOUT+
Figure 1. Required Input Signal and Output Polarity
MAX3646
21Ω
21Ω
50Ω
OUT+
OUT-
OSCILLOSCOPE
50Ω
1μF
BIAS-T
BIAS-T
1μF
Figure 2. Test Circuit for Characterization
1μH
0.1μF
0.1μF
10μF
VOLTAGE
SUPPLY
SOURCE
NOISEOPTIONAL
OPTIONAL
FILTER DEFINED BY SFP MSA
HOST BOARDMODULE
TO LASER
DRIVER VCC
Figure 3. SupplyFilter
MAX3646
Average power is regulated using APC, which keeps
constant current from a photodiode coupled to the
laser. Peak-to-peak power is maintained by compen-
sating the modulation current for reduced slope effi-
ciency (η) of laser over time and temperature:
PAVG= IMD/ρMON
PP-P= ηx IMOD
Modulation compensation from bias increases the mod-
ulation current by a user-selected proportion (K) needed
to maintain peak-to-peak laser power as bias current
increases with temperature. Refer to Application Note
1119: HFAN-02.2.1: Maintaining the Extinction Ratio of
Optical Transmitters Using K-Factor Controlfor details:
K = ΔIMOD/ ΔIBIAS
This provides a first-order approximation of the current
increase needed to maintain peak-to-peak power.
Slope efficiency decreases more rapidly as tempera-
ture increases. The MAX3646 provides additional tem-
perature compensation as temperature increases past
a user-defined threshold (TTH).
155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
MAX3646
IN+
IN-
OUT-
OUT+
INPUT BUFFER
DATA
PATH
IMOD
VBG
RMODSET
MODSET
VBGRAPCSETAPCSET
IAPCSET
CAPC
APCFILT1APCFILT2
IBIAS
BIAS
VCC
IBIAS
ENABLE
TX_FAULT
TX_DISABLE
SAFETY LOGIC
AND
POWER DETECTOR
RBC_MON
BC_MON
VCC
RPC_MON
PC_MON
VCC
IMD
CMD
SHUTDOWN
SHUTDOWN
x268
RPULL = 45kΩxTC
T > TTH
IBIAS
IMOD
ENABLE
x1/2
MODTCOMP
RMODTCOMP
TH_TEMP
RTH_TEMP
MODBCOMP
RMODBCOMP
IBIAS
IMD
Figure 4. Functional Diagram

Partno	Mfg	Dc	Qty	Available	Descript
MAX3646ETG+T \|MAX3646ETGT	MAXIM	N/a	15000	avai	155Mbps to 622Mbps SFF/SFP Laser Driver with Extinction Ratio Control