19-1645; Rev 0; 1/00
MAX3289 Longwave (Common Anode)
Evaluation Kit
General Description
The MAX3289 evaluation kit (EV kit) is an assembled,
surface-mount demonstration board that provides easy
optical and electrical evaluation of the MAX3289
1.25Gbps laser driver or the MAX3299 2.5Gbps laser
driver in the common-anode configuration. This config-
uration allows evaluation of the MAX3289/MAX3299
with long-wavelength laser diodes. Long-wavelength
(1310nm and greater) laser diodes are typically pack-
aged with the laser diode’s anode connected to the
photodetector’s cathode.
o
Drives Common-Anode Lasers
o
Socket for Laser Insertion
o
LED Fault Indicator
o
Evaluates Either MAX3289 (installed) or MAX3299
o
Adjustable Laser Bias Current
o
Adjustable Laser Modulation-Current
Temperature Coefficient
o
Configured for Electrical Operation, No Laser
Necessary
Features
Evaluates: MAX3289/MAX3299
Ordering Information
PART
MAX3289EVKIT
*Exposed Pad
TEMP. RANGE
0°C to +70°C
IC PACKAGE
16 TSSOP-EP*
Component List
DESIGNATION QTY
C7, C9, C10,
C15, C16, C21,
C26, C44, C48,
C49
C18
C24
C33
C50
D2
L2
L3, L6
L7
JU2
JU10
J8, J9
TP1, TP2,
TP11, TP12,
TP13
10
0
1
1
1
0
1
2
1
1
1
2
DESCRIPTION
0.01µF, 10V min ±10% X7R ceramic
capacitors (0402)
Open, user supplied (0402)**
10µF, 16V ±10% tantalum capacitor
AVX TAJC106K016
0.01µF, 10V min ±10% X7R ceramic
capacitor (0603)
0.1µF, 10V min ±10% X7R ceramic
capacitor (0603)
Open, user supplied (laser diode and
photodiode assembly, Figure 1)
Ferrite bead, included but not installed
Murata BLM11HA102SG
Ferrite beads
Murata BLM11HA102SG
Ferrite bead
Murata BLM11HA601SG
3-pin header (0.1in centers)
2-pin header (0.1in centers)
Digi-Key S1012-36-ND
Test points
Mouser 151-203
Test points
Mouser 151-203
R8
R15, R40
R16
R17
R19
R27
R39
J11, J12, J16
Q3
Q7
U1
U6
1
2
1
1
1
1
1
3
1
1
2
1
DESIGNATION QTY
R1
R6
R7, R14
1
1
2
DESCRIPTION
0Ω resistor (0402)
115Ω ±1% resistor (0402)
100kΩ variable resistors
Bourns Digi-Key 3296W-104-ND
50kΩ variable resistor
Bourns Digi-Key 3296W-503-ND
36Ω ±5% resistors (0603)
18Ω ±5% resistor (0402)
24.9Ω ±1% (0402)**
49.9Ω ±1% resistor (0402)
6.8Ω ±1% resistor (0402)
1kΩ ±5% resistor (0402)
SMA connectors (edgemount)
EFJohnson 142-0701-801 or
Digi-Key J502-ND
Zetex FMMT491A
Zetex FMMT591A
Installed: MAX3289CUE (16-pin
TSSOP-EP); included but not installed:
MAX3299CUE (16-pin TSSOP-EP)
MAX4322EUK (5-pin SOT23)
5
**These items are part of the compensation network that reduces
overshoot and ringing. Parasitic series inductance introduces a
zero into the laser’s frequency response. R18 and C17 add a
pole to cancel this zero. The optimal values depend upon the
laser used. Maxim recommends C18 = 2pF and R17 = 24.9Ω
as a starting point.
1
________________________________________________________________
Maxim Integrated Products
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX3289 Longwave (Common Anode)
Evaluation Kit
Evaluates: MAX3289/MAX3299
Electrical Quick Start with
Simulated Photodiode Feedback
1) Short shunts SP9 and SP10 to use the photodiode
emulator circuitry (see
Emulating a Photodiode
During Electrical Evaluation).
2) Make sure nothing is installed in the laser socket
(Figure 1).
3) Ensure that R27 is installed.
4) Ensure that L2 is not installed.
5) Confirm that C18 is open. Since the laser is not
installed, no compensation network is required.
6) Set the R14 (R
SET
) potentiometer to midscale by
turning the screw clockwise until a faint click is felt,
then counterclockwise for 15 full revolutions (30 full
revolutions in the 0 to 100kΩ range of the multiturn
potentiometer). This sets the regulation point for the
simulated photodiode current to 1.7V / 50kΩ =
34µA. The photodiode emulator circuit regulates
the DC bias current into Q3 to 28
·
34µA
≅
1mA.
7) Set the R8 (R
MOD
) potentiometer to maximum resis-
tance by turning the screw counterclockwise until a
faint click is felt (30 full revolutions in the 0 to 50kΩ
range of the multiturn potentiometer). This mini-
mizes the modulation current.
8) Set the R7 (R
TC
) potentiometer to maximum resis-
tance by turning the screw counterclockwise until a
faint click is felt (30 full revolutions in the 0 to 100kΩ
range of the multiturn potentiometer). This mini-
mizes the temperature coefficient of the modulation
current.
9) Ensure there is no jumper on JU10 (FLTDLY). This
enables the safety circuitry.
10) Attach a 50Ω characteristic impedance cable
between the J16 SMA output connector and the
input of the oscilloscope. Ensure the oscilloscope
input is 50Ω terminated.
11) Attach differential sources to SMA connectors J11
and J12. Each source should have peak-to-peak
amplitude between 100mV and 830mV.
12) Apply either +3.3V or +5V power to the board at the
J8 (VCC) and J9 (GND) test points. Put a jumper
across pins 1 and 2 of JU2. Set the current limit to
300mA.
13) While monitoring the voltage between TP2 and
TP13, adjust R14 (R
SET
) until the desired DC bias
current is obtained. Turning the R14 potentiometer
screw counterclockwise increases the DC bias cur-
rent.
14) While monitoring the J16 SMA connector output on
the oscilloscope, adjust R8 (R
MOD
) until the desired
2
modulation current is obtained. Turning the R8
potentiometer screw clockwise increases the modu-
lation current.
Optical Quick Start with
Photodiode Feedback
1) Ensure that SP9 and SP10 are open. This ensures
that the photodiode emulator circuitry is not con-
nected.
2) Remove R27.
3) Install L2.
4) Connect a laser to the board (Figure 1).
5) Set the R14 (R
SET
) potentiometer to maximum resis-
tance by turning the screw counterclockwise until a
faint click is felt, then counterclockwise for 15 full
revolutions (30 full revolutions in the 0 to 100kΩ
range of the multiturn potentiometer). This sets the
regulation point for the photodiode current to 1.7V /
50kΩ = 34µA. The resulting laser bias current
depends upon the relationship between laser
power and photodiode output current.
WARNING:
Consult your laser data sheet to ensure that 34µA of
photodiode monitor current does not correspond to
excessive laser power.
6) Set the R8 (R
MOD
) potentiometer to maximum resis-
tance by turning the screw counterclockwise until a
faint click is felt (30 full revolutions in the 0 to 50kΩ
range of the multiturn potentiometer). This mini-
mizes the modulation current (AC drive applied to
laser).
7) Set the R7 (R
TC
) potentiometer to maximum resis-
tance by turning the screw counterclockwise until a
faint click is felt (30 full revolutions in the 0 to 100kΩ
range of the multiturn potentiometer). This mini-
mizes the temperature coefficient of the modulation
current.
8) Attach a 50Ω SMA terminator to J16 to match the
laser loading.
9) Ensure there is no jumper on JU10 (FLTDLY). This
enables the safety circuitry.
10) Attach differential sources to SMA connectors J11
and J12. Each source should have peak-to-peak
amplitude between 100mV and 830mV.
11) Apply either +3.3V or +5V power to the board at the
J8 (VCC) and J9 (GND) test points. Put a jumper
across pins 1 and 2 of JU2. Set the current limit to
300mA.
12) While monitoring the laser output, adjust R14 (R
SET
)
until the desired laser bias current is obtained.
Turning the R14 potentiometer screw counterclock-
wise increases the laser bias current.
_______________________________________________________________________________________
MAX3289 Longwave (Common Anode)
Evaluation Kit
Evaluates: MAX3289/MAX3299
Table 1. Adjustment and Control Descriptions
DESIGNATION
JU2
JU10
R7
NAME
–
FLTDLY
R
TC
FUNCTION
Placing a jumper between pins 1 and 2 of JU2 applies power to the upper prestuffed
circuit. Placing a jumper between pins 2 and 3 of JU2 applies power to the lower
unstuffed circuit.
Placing a jumper on JU10 disables the laser driver safety features.
Potentiometer R7, in conjunction with potentiometer R8 (R
MOD
), sets the temperature
coefficient of the laser modulation current. Turn the potentiometer screw counterclock-
wise to increase resistance. The temperature coefficient decreases when the poten-
tiometer screw turns counterclockwise.
Potentiometer R8, in conjunction with potentiometer R7 (R
TC
), sets the peak-to-peak
amplitude of the laser modulation current. Turn the potentiometer screw counterclock-
wise to increase resistance. The laser modulation current amplitude decreases when
the potentiometer screws turn counterclockwise.
Potentiometer R14 adjusts the desired laser DC-current bias point. Potentiometer R14
sets the resistance from MD to ground. MD regulates to 1.77V. Turn the potentiometer
screw clockwise to increase resistance. The total range is 0 to 100kΩ. The laser
average power increases when the potentiometer screws turn counterclockwise.
Short across these shunts with a bridge of solder when performing electrical evaluation.
R8
R
MOD
R14
SP9, SP10
R
SET
–
13) While monitoring the laser output, adjust R8 (R
MOD
)
until the desired modulation current is obtained.
Turning the R8 potentiometer screw clockwise
increases the laser modulation current.
1) Use solder wick to remove as much solder as pos-
sible from the MAX3289’s leads.
2) Using a small metal pick, heat each lead and gently
lift it from its pad, being careful not to damage the
underlying trace.
3) Flip the board over and notice that there is a hole
underneath the exposed pad of the MAX3289 in the
middle of the thermal pad. Place the tip of a solder-
ing iron into the hole in the thermal pad. The
MAX3289 should fall away from the board.
4) Use solder wick to remove any residual solder
around the thermal pad.
Once the MAX3289 has been removed, the MAX3299
may be mounted.
Detailed Description
Emulating a Photodiode
During Electrical Evaluation
When evaluating the MAX3289/MAX3299 without a
laser, the IC’s DC bias circuitry operates using a photo-
diode emulator circuit. When shunts SP9 and SP10 are
shorted, U6 (MAX4322), Q7, and R39 form a current-
controlled current source that emulates the behavior of
the photodiode in the laser assembly. R40 takes the
place of the laser diode, and the photodiode emulator
circuitry sources a current from the collector of Q7 that
is a fraction of the current through R40. This simulates
the behavior of a laser diode and photodiode assembly
where a fraction of the laser light reflects onto the pho-
todiode, which then outputs a small current proportion-
al to the light emitted.
S
M
A
4
Evaluating the MAX3299
The MAX3289 longwave (common-anode) evaluation
kit is shipped with the MAX3289 installed in the circuit.
To evaluate the MAX3299, remove the MAX3289 from
the board. The MAX3289 comes in an exposed-pad
package. The exposed pad is an area of exposed
metal lead frame underneath the 16-pin package that is
soldered to a copper thermal pad. To remove the
MAX3289 follow these steps:
1
3
MAX3289
MAX3299
2
1 = PHOTODIODE ANODE
2, 4 = VCC
3 = LASER-DIODE CATHODE
Figure 1. Optical Connection Diagram
3
_______________________________________________________________________________________
Evaluates: MAX3289/MAX3299
VCC2
VCC
R39
1k
VCC
R16
18Ω
C44
0.01µF
R40
36Ω
4
U6
3
MAX4322
1
Q7
R27
6.8Ω
TP13
R1
0Ω
VCC
J16
D2
C33
0.01µF
R19
49.9Ω
TP12
MAX3289 Longwave (Common Anode)
Evaluation Kit
4
C24
10µF
VCC
C26
0.01µF
3
2 JU2
1
R17
24.9Ω
C15
0.01µF
VCC
C18
OPEN
L6
C16
0.01µF
L2
L3
C49
0.01µF
TP1
TP11
SP9
SP10
VCC
C50
0.1µF
16
15
VCC
VCC
OUT-
OUT+
MODSET
BIASDRV
SHDNDRV
14
13
12
11
10
TC
9
VCC1
J8
L7
J9
GND
Figure 2. MAX3289 EV Kit Schematic
Q3
R15
36Ω
1
R
SET
2
R14
100k
3
VCC
C48
0.01µF
R
MOD
R8
50k
R
TC
R7
100k
U1
MAX3289
VCC
MD
REF
GND
IN+
IN-
3
4
5
6
8
7
1
2
FLTDLY
GND
FLTDLY
R6
115Ω
1%
TP2
VCC
C7
0.01µF
J12
J11
C9
0.01µF
C10
0.01µF
_______________________________________________________________________________________
2
JU10
C21
0.01µF
1
NOTE: EXCEPT FOR U4, ALL COMPONENTS ARE
USER SUPPLIED; VALUES ARE FOR REFERENCE ONLY.
R33
18Ω
C43
OPEN
C41
0.01µF
R34
24.9Ω
L11
VCC2
VCC2
R35
24.9Ω
VCC2
D5
C39
0.01µF
C42
0.01µF
R31
OPEN
L1
VCC2
R36
OPEN
C45
0.01µF
Figure 2. MAX3289 EV Kit Schematic (continued)
VCC2
L10
16
15
10
BIASDRV
SHDNDRV
14
13
12
11
9
C51
0.1µF
Q5
R4
36Ω
1
C35
OPEN
VCC2
C36
0.01µF
R43
115Ω
R2
OPEN
TC
VCC
VCC
OUT-
OUT+
MODSET
U4
MAX3289
MD
VCC
GND
REF
IN+
IN-
3
4
5
6
8
7
2
FLTDLY
GND
C37
0.01µF
C38
0.01µF
Evaluates: MAX3289/MAX3299
_______________________________________________________________________________________
J13
J14
MAX3289 Longwave (Common Anode)
Evaluation Kit
5
NXP MCU
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