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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
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MAX3656 Evaluation Kit
Evaluates: MAX3656
General Description
The MAX3656 evaluation kit (EV kit) is an assembled
demonstration board that provides optical evaluation of
the MAX3656 155Mbps to 2.5Gbps burst-mode laser
driver. The evaluation board allows connection with
coaxial laser packages as well as BIDI packages.
EV Kit Contents
S MAX3656 EV Kit Board
Features
S Fully Assembled and Tested
S Adjustable Laser Bias Current
S Adjustable Laser Modulation Current
S Single +3.3V Power-Supply Operation
Ordering Information
Component List
19-2903; Rev 2; 8/10
+Denotes lead(Pb)-free and RoHS compliant.
*EP = Exposed pad.
PART TYPE
MAX3656EVKIT+ EV Kit
DESIGNATION QTY DESCRIPTION
C1 1
1FF Q10% ceramic capacitor
(0402)
Murata GRM155R61A105KE15D
C2 1
1000pF Q10% ceramic capacitor
(0402)
Murata GRM155R71H102KA01D
C3, C10–C15 7
0.1FF Q10% ceramic capacitors
(0402)
Murata GRM155R61A104KA01D
C19 1
10FF Q10% tantalum capacitor
(B case)
AVX TAJB106K010RNJ
C20 1
0.1FF Q10% ceramic capacitor
(0603)
Murata GRM188R71H104KA93D
C21 1
0.01FF Q10% ceramic capacitor
(0603)
TDK C1005X8R1E103K
C24 1
27pF Q5% ceramic capacitor
(0402)
Murata GRM1555C1H270JZ01D
D2 1 Green LED, SMD
Panasonic LNJ311G8PRA
D3, D4 2 Diodes
Panasonic MA27P0100L
D5 0 Laser, user supplied
J18, J20, TP1,
TP2 4Test points
Keystone 5000
J23–J26 4
SMA connectors, edge mount,
tab contact
Johnson 142-0701-851
DESIGNATION QTY DESCRIPTION
JP26, JP28,
JP30, JP32, JP33 53-pin headers, 0.1in center
Sullins PEC36SAAN
JP26, JP28,
JP30, JP32, JP33 5Shunts
Sullins SSC02SYAN
L1 1 10nH Q5% inductor (0402)
Murata LQG15HS10NJ02
Q1 1 npn transistor
Zetex FMMT491ATA
R1 1 15I Q5% resistor (0402)
R2, R3 2 10I Q5% resistors (0402)
R12, R126 2 5.6I Q5% resistors (0402)
R43 1 200I Q5% resistor (0603)
R59, R79, R90 3 50kI variable resistors
Bourns 3296W-1-503LF
R61, R82, R118 0 Not installed, resistors (0603)
R88 1 4.3kI Q5% resistor (0603)
R91, R92, R94,
R95, R97, R98,
R100, R101
0 Not installed, resistors (0402)
R103, R104 2 100I Q1% resistors (0402)
R113–R116 4 0I Q5% resistors (0402)
R119 1 3kI Q5% resistor (0603)
R120 1 1.5kI Q5% resistor (0603)
R121 1 75I Q5% resistor (0402)
U1 1
Burst-mode laser driver
(24 TQFN-EP*)
Maxim MAX3656ETG+
— 1 PCB: MAX3656 EVALUATION
BOARD+, Rev D
MAX3656 Evaluation Kit
Evaluates: MAX3656
2 ______________________________________________________________________________________
Quick Start
To evaluate the MAX3656 with a laser diode, configure
the EV kit as follows:
1) Pull shunts off all jumpers (JP33, JP30, JP32, JP26,
and JP28).
2) Set RAPCSET to 20kI by adjusting the APCSET
variable resistor R79 until the measured resistance
between the VAR pin of jumper JP33 and GND is
20kI. Then install a shunt on the VAR side of jumper
JP33.
3) Set RMODSET to 20kI by adjusting the MODSET
variable resistor R59 until the measured resistance
between the VAR pin of jumper JP30 and GND is
20kI. Then install a shunt on the VAR side of jumper
JP30.
4) Set RBIASMAX to 7kI by adjusting the BIASMAX
variable resistor R90 until the measured resistance
between the VAR pin of jumper JP32 and GND is
7kI. Then install a shunt on the VAR side of jumper
JP32.
5) Connect the EN pin to GND by installing a shunt on
the GND side of jumper JP26.
6) Connect the LONGB pin to GND by installing a shunt
on the GND side of jumper JP28.
7) Solder a laser to edge connection D5. See Figure 1
for a view of how the laser should be mounted on the
EV kit. Be sure to keep the laser leads as short as
possible to minimize parasitic inductance.
8) Connect a differential data source to IN+ (J26) and
IN- (J25) and a differential burst-enable source
to BEN+ (J24) and BEN- (J23). Make sure the
differential signals are between 200mVP-P and
1600mVP-P and the common-mode is between
(VCC - 1.49V) and (VCC - VIN/4). See the Applications
Information section for more options.
9) Attach a +3.3V power supply to J18 (+3.3V) and J20
(GND). Set the current limit to 250mA.
10) Connect the output of the user-supplied laser
to an optical-to-electrical converter that has the
appropriate bandwidth (filter) for the intended
application.
11) Turn on the power supply and adjust APCSET (R79)
for the desired average optical power, then adjust
MODSET (R59) for the desired extinction ratio.
Note: The APC loop is functional when the FAIL
indicator, green LED D2, is on. The LED is off if the
BIASMAX is set too low, the monitor diode (MD) pin
is not connected, or the modulation current is set too
high.
12) If the eye diagram contains too much overshoot or
the rise/fall times are too slow, experimentally adjust
the values of the RL peaking network (R3, L1) and
RC shunt network (R121, C24) to better match the
characteristics of the laser.
Applications Information
Continuous Mode Operation
For continuous mode operation, switch the differential
burst-enable input (BENQ) to a constant high in one of
two ways:
• RemoveresistorR103.Installa1kI resistor on R101
and 3kI resistors on R91, R92, and R100.
• Connect a +2.3V supply to BEN+ and a +1.7V
supply to BEN- (or a differential 0.6V supply between
BEN+ and BEN-).
LVPECL Input Terminations
If needed, an LVPECL Thevenin equivalent load
termination of 50I to (VCC - 2V) can be created by doing
the following:
• RemoveresistorsR103andR104.
• Solder130I resistors on R92, R94, R98, and R101.
• Solder82I resistors on R91, R95, R97, and R100.
For more information, refer to Application Note 291:
HFAN-01.0: Introduction to LVDS, PECL, and CML.
LVCMOS Burst Enable
To drive the burst-enable input (BEN+) with single-
ended LVCMOS levels, do the following:
• RemoveresistorsR103andR114.
• Solder3kI resistor on R114.
• Solder5kI resistors on R101 and R92.
• Solder9kI resistor on R91.
MAX3656 Evaluation Kit
Evaluates: MAX3656
_______________________________________________________________________________________ 3
Figure 1. Laser Attachment
Table 1. Adjustment and Control Descriptions
TOP OF PCB
BOTTOM OF PCB
LD
PD
COMPONENT NAME FUNCTION
JP33 APCSET SELECT This jumper connects a fixed resistance (R82, not installed) or a variable
resistance (R120 + R79) between the APCSET pin and GND.
R79 APCSET RESISTOR
This 50kI variable resistor, in addition to a 1.5kI series resistor (R120), sets the
external resistance between the APCSET pin and GND when a shunt is installed
on the VAR side of jumper JP33. Turning the variable resistor clockwise increases
the average optical power.
JP30 MODSET SELECT This jumper connects a fixed resistance (R61, not installed) or a variable
resistance (R119 + R59) between the MODSET pin and GND.
R59 MODSET RESISTOR
This 50kI variable resistor, in addition to a 3kI series resistor (R119), sets the
external resistance between the MODSET pin and GND when a shunt is installed
on the VAR side of jumper JP30. Turning the variable resistor clockwise increases
the modulation current and extinction ratio.
JP32 BIASMAX SELECT This jumper connects a fixed resistance (R118, not installed) or a variable
resistance (R88 + R90) between the BIASMAX pin and GND.
R90 BIASMAX
RESISTOR
This 50kI variable resistor, in addition to a 4.3kI series resistor (R88), sets the
external resistance between the BIASMAX pin and GND when a shunt is installed
on the VAR side of jumper JP32. Turning the variable resistor clockwise increases
the maximum bias current.
JP26 EN This jumper is used to connect the EN pin to VCC (driver disabled) or to GND
(driver enabled).
JP28 LONGB This jumper is used to connect the LONGB pin to VCC (burst on-time > 1.2Fs) or
to GND (burst on-time ≤ 1.2Fs).
D2 FAIL
The APC loop is functional when the LED is on. The LED is off if the BIASMAX is
set too low, the monitor diode (MD) pin is not connected, or the modulation
current is set too high.
MAX3656 Evaluation Kit
Evaluates: MAX3656
4 ______________________________________________________________________________________
Figure 2. MAX3656 EV Kit Schematic
MAX3656 Evaluation Kit
Evaluates: MAX3656
_______________________________________________________________________________________ 5
Figure 3. MAX3656 EV Kit Component Placement Guide—Component Side
MAX3656 Evaluation Kit
Evaluates: MAX3656
6 ______________________________________________________________________________________
Figure 4. MAX3656 EV Kit PCB Layout—Component Side
MAX3656 Evaluation Kit
Evaluates: MAX3656
_______________________________________________________________________________________ 7
Figure 5. MAX3656 EV Kit PCB Layout—Ground Plane
MAX3656 Evaluation Kit
Evaluates: MAX3656
8 ______________________________________________________________________________________
Figure 6. MAX3656 EV Kit PCB Layout—Power Plane
MAX3656 Evaluation Kit
Evaluates: MAX3656
_______________________________________________________________________________________ 9
Figure 7. MAX3656 EV Kit PCB Layout—Solder Side
MAX3656 Evaluation Kit
Evaluates: MAX3656
10 _____________________________________________________________________________________
Figure 8. MAX3656 EV Kit Component Placement Guide—Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 11
© 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX3656 Evaluation Kit
Evaluates: MAX3656
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 7/03 Initial release —
1 10/04
Corrected the electrical and optical component list, corrected the quick start
steps, added text about diodes to OUT- and BIAS-, corrected the schematics and
replaced the layout figures
1-4, 7-11
2 8/10 Redesigned the EV kit to work up to 2.5Gbps All
