General Description
The MAX3766 evaluation kit (EV kit) is an assembled,
surface-mount demonstration board that provides easy
optical or electrical evaluation of the MAX3766
622Mbps laser driver.
____________________________Features
♦Adjustable Modulation Temperature Coefficient
♦Automatic Safety Reset Delay with MAX809M
♦Automatic Power Control Evaluation in Electrical
and Optical Configuration
♦Dual Layout Option on Single Board
♦Fully Assembled and Tested
Evaluates: MAX3766
MAX3766 Evaluation Kit
________________________________________________________________
Maxim Integrated Products
1
19-4755; Rev 0; 12/97
Component List
Ordering Information
PART
MAX3766EVKIT -40°C to +85°C
TEMP. RANGE PIN-PACKAGE
MAX3766EEP
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
DESIGNATION QTY DESCRIPTION
B1 1 Ferrite bead
Murata BLM11A601S
C4, C7, C10,
C11, C15, C18 60.1µF 10%, 25V min ceramic
capacitors
C8, C9 2 DO NOT INSTALL
C16 1 15pF 10%, 25V min ceramic
capacitor
C17 1 1µF 10%, 10V min ceramic
AVX0805ZC105k
D1 SOCKETS 4 Pin sockets
Digi-Key ED5042-ND
JU5 1 2-pin header (0.1" center)
Digi-Key S1012-36-ND
IN+, IN-,
IOUT- 3SMA connectors (edge mount)
E.F. Johnson 142-0701-801 or
Digi-Key J502-ND
JU1, JU3, JU4 3 3-pin headers (0.1" centers)
Digi-Key S1012-36-ND
JU1, JU3,
JU4, JU5 4Shunts
Digi-Key S9000-ND
C1 1 10µF ±10%, 16V min tantalum cap
AVX TAJC106K016
C2, C12, C14 3 0.01µF 10%, 25V min ceramic
capacitors
DESIGNATION QTY DESCRIPTION
L1 1 DO NOT INSTALL
Q1 1 PNP transistor
Zetex FMMT591, SOT23
R1 1 0Ωjumper
R2, R6, R9 3 50kΩvariable resistors
Bourns 3296
R3, R12 2 221Ω, 1% resistors
R4 1 20Ω, 5% resistor
R5, R7 2 100kΩvariable resistors
Bourns 3296
R8, R20 2 5.1kΩ, 5% resistors
R10, R11 2 68.1Ω, 1% resistors
R13 1 10Ω, 5% resistor
R14 1 24.9Ω, 1% resistor
R15, R16 2 182Ω, 1% resistors
R17 1 33.2Ω, 1% resistor
R18 1 100kΩ, 5% resistor
R21 1 49.9Ω, 1% resistor
U1 1 MAX3766EEP, QSOP-20
U2 1 MAX495ESA, SOIC-8
U3 1 MAX809MEUR-T
+5V, GND 2 Test points
Mouser 151-203
None 1 MAX3766 circuit board (rev. C)
None 1 MAX3766 data sheet
______________Electrical Quick Start
1) Ensure that solder bridges JU7 and JU6 are shorted,
and that solder bridge JU2 is open.
2) Install a shunt on JU5.
3) Install a shunt on JU3 between pins 2 and 3.
4) Install a shunt on JU1 between pins 2 and 3 (all fail
conditions ignored).
5) Remove the shunt from JU4.
6) Turn the RTC potentiometer counterclockwise to
0kΩ(minimum tempco). Also turn the RBIASMAX
potentiometer clockwise to 0kΩ.
7) Connect a 50Ωterminated oscilloscope from a 50Ω
cable to IOUT-. Set the oscilloscope vertical gain to
100mV/div.
8) Apply a 500mV minimum differential input signal at
IN- (J1) and IN+ (J2).
9) Power up the board with a 5V supply at the +5V
and GND test pins. Set the current limit to 300mA.
10) Adjust RMODSET until a signal appears on the
oscilloscope. The conversion gain from the
MAX3766 modulation current to the oscilloscope
output is 0.08mA/mV; therefore 750mV equals a
modulation current of 60mA.
Optical Quick Start
1) Ensure that solder bridges JU7 and JU2 are open.
2) Ensure that solder bridge JU6 is shorted.
3) Install a shunt on JU3 and JU4, between pins 2 and 3.
4) Install a shunt on JU1 between pins 2 and 3 (all fail
conditions ignored).
5) Turn the RTC potentiometer counterclockwise to
0kΩ(minimum tempco).
6) Adjust the RBIASMAX potentiometer to a safe maxi-
mum biasing level for the laser diode used in this
evaluation. Measure RBIASMAX from VREF1 to
BIASMAX without power applied to the board.
(From the MAX3766 data sheet it can be estimated
that 1kΩsets up about 40mA of maximum laser
bias current.)
7) Turn RMODSET counterclockwise to 50kΩ(mini-
mum modulation current).
8) Turn RPOWERSET counterclockwise to 100kΩ
(minimum monitor diode (MD) current).
9) Insert a TO-46 packaged laser into D1.
10) Power up the board with a 5V supply at the +5V
and GND test points. Set the current limit to 300mA.
11) Connect a 50Ωcable from IOUT- to a 50Ωterminat-
ed oscilloscope input.
12) Apply a 500mV minimum differential input signal at
IN- (J1) and IN+ (J2).
13) Adjust RPOWERSET and RMODSET clockwise until
the desired average optical power and amplitude
are displayed on the oscilloscope attached to the
optical-to-electrical converter. (
Use caution
: the
modulation current could exceed the laser’s dam-
age rating.)
Compact Layout
A second, more compact layout is provided on this
EV kit PC board. It is designed for optical evaluation
only. The schematic is included (Figure 2), but no com-
ponents are supplied. High-speed performance can be
improved with the compact layout.
Laser Safety and IEC 825
Using the MAX3766 laser driver alone does not ensure
that a transmitter design is compliant with IEC 825 eye
safety requirements. The entire transmitter circuit and
component selections must be considered. Each cus-
tomer must determine the level of fault tolerance
required by their application, recognizing that Maxim
products are not designed or authorized for use as
components in systems intended for surgical implant
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 per-
sonal injury or death may occur.
Evaluates: MAX3766
MAX3766 Evaluation Kit
2 _______________________________________________________________________________________
SUPPLIER PHONE FAX
AVX (806) 946-0690 (803) 626-3123
Murata (770) 436-1300 (770) 436-3030
Zetex (516) 543-7100 (516) 864-7630
Component Suppliers
Evaluates: MAX3766
MAX3766 Evaluation Kit
_______________________________________________________________________________________ 3
Table 1. Adjustment and Control Descriptions (review Quick Start first)
CONTROL NAME FUNCTION
D1 Laser Diode This is a socket for a laser in a TO-46 header (customer supplied).
JU1 SAFETY
When the JU1 shunt is placed on pins 1 and 2, the MAX3766’s safety features
are enabled. The MAX809M ensures that failures at start-up are ignored until the
voltage level set by the MAX809M is detected on VCC. This allows the MAX3766
to power up without generating a safety shutdown.
Shunting pins 2 and 3 disables safety shutdown.
JU2 — This solder bridge should be shorted only for electrical evaluation when using
automatic power control.
JU5 ENABLE Enables and disables the MAX3766. When shunted, the part is enabled.
JU7 — This solder bridge should be open for optical evaluation and shorted for
electrical evaluation.
R2 COUPLING When using the electrically emulated monitor diode current, R2 sets the ratio of
laser current to monitor diode current.
R6 RBIASMAX When in open-loop mode (automatic power control not used), this resistance
sets the laser bias current (0kΩ= maximum bias). When in closed-loop mode, it
sets the maximum bias current available with automatic power control.
R7 RPOWERSET Sets the monitor diode reference current in a closed-loop condition (automatic
power control engaged). See MAX3766 data sheet for selection of RPOWERSET.
JU4 MD Allows board to switch between optical monitor diode current (shunt pins 2
and 3) and electrically-emulated monitor diode current (shunt pins 1 and 2).
JU6 — This solder bridge should be shorted.
JU3 VCC/VCCA Selects which EV kit layout to supply with power. Shunt pins 1 and 2 to power up
U1 (larger layout). Shunt pins 2 and 3 to power up U4 (compact layout).
R5 RTC RTC sets the modulation current temperature compensation, 0kΩ= minimum
tempco (0ppm/°C) to 100kΩ= maximum tempco (~5600ppm/°C).
R9 RMODSET Sets modulation current. 0kΩ= maximum modulation current.
Evaluates: MAX3766
MAX3766 Evaluation Kit
4 _______________________________________________________________________________________
BIASMAX
TC
REF2
MOD
GND
IN-
IN+
GND
VCC
ENABLE
1
2
3
4
5
6
7
8
9
10
TP3
TC
TP2
BIASMAX
TP7
VMD
TP4
VREF2
TP5
MODSET
TP6
FAIL
C10
0.1µF
R5
100k
RTC
R9
50k
R11
68.1Ω
1%
R10
68.1Ω
1%
R16
182Ω
1%
R15
182Ω
1%
R6
50k R7
100k
TP1
VREF1
R2
50k
TP9
VBIAS
C11
0.1µF
RMODSET
JU5
JU1
20
19
18
17
16
15
14
13
12
11
REF1
POWERSET
MD
GNDOUT
BIAS
OUT+
OUT-
VCCOUT
FAIL
SAFETY
IN-
J1
SMA
IN+
J2
SMA
MAX3766
U1
L1
OPEN
VCC
VCC
VCC
VCC
VCC
VCC
VCC
VCCA
GND
+5V
VCC
VCC
JU4
JU6
R17
33.2Ω
C9
OPEN
VCC
C7
0.1µFVCC
R21
49.9
1%
R12
221Ω
R3
221Ω
R13
10Ω
R14
24.9Ω
C18
0.1µF
C15
0.1µF
C4
0.1µF
SMA
TP8
PWRSET
J3
R18
100k
R8
5.1k
R20
5.1k
IOUT-
C14
0.01µF
C17
1µF
VCC VCC
VCC
C2
0.01µF
C16
15pF
C8
OPEN
1
1
22 3
3
32
1
1
1
3
3
1
3
R1
0Ω
1
3
2JU3
2
21
1
33
2
7
6
4
Q1
3
2
2
2
RBIASMAX
RPOWERSET
COUPLING
VCC
C1
10µF
16V
VCC
RESET
GND
MAX809M
U3
JU2
R4
20Ω
JU7
C12
0.01µF
VCC
B1
FERRITE 34
D1
LASER
1 2
U2
MAX495
Figure 1. MAX3766 EV Kit Schematic
Evaluates: MAX3766
MAX3766 Evaluation Kit
_______________________________________________________________________________________ 5
BIASMAX
TC
REF2
MOD
GND
IN-
IN+
GND
VCC
ENABLE
1
2
3
4
5
6
7
8
9
10
C23
0.1µF
20
19
16
15
14
13
12
11
REF1
POWERSET
BIAS
OUT+
OUT-
VCCOUT
FAIL
SAFETY
SMA
MAX3766
U4
C21
0.01µF
R31
24.9Ω, 1%
C20
15pF
C24
OPEN
C22
0.1µF
R32
24.9Ω
1%
R29
5.1k
R23
C19
1µF
C13
0.01µF
VCCA
VCCA
B2
FERRITE
R30
10Ω, 5%
VCCA
VCCA
IP10
VCC
VCCA
3 4
D2
LASER
1 2
VCCA
IN+
R25
68.1Ω
1%
R26
182Ω
1%
R28
182Ω
1%
R27
68.1Ω
1%
R24
R22
R19
GNDOUT 17
MD 18
Figure 2. MAX3766 EV Kit Compact Layout (components not supplied, values are for reference only)
DESIGNATION QTY DESCRIPTION
B2 1 Ferrite bead
Murata BLM11A601S
C20 1 15pF capacitor
C22, C23 2 0.1µF capacitors
C24 0 DO NOT INSTALL
D2 SOCKET 4 Pin sockets
Digi Key ED5042-ND
C13, C21 2 0.01µF capacitors
C19 1 1µF capacitor
DESIGNATION QTY DESCRIPTION
R19, R22,
R23, R24 4 Resistors see (MAX3766 data sheet)
R29 1 5.1k, 5% resistor
R30 1 10Ω, 5% resistor
R31, R32 2 24.9, 1% resistors
R25, R27 2 68.1Ω, 1% resistors
R26, R28 2 182Ω, 1% resistors
IN+ 1 SMA connector (edge mount)
E.F. Johnson 142-0701-801 or
Digi Key J502-ND
U4 1 MAX3766EEP QSOP-20
Compact Layout Component List (Not Installed and Not Supplied)
Evaluates: MAX3766
MAX3766 Evaluation Kit
6 _______________________________________________________________________________________
Figure 3. MAX3766 EV Kit Component Placement Guide—
Component Side
Figure 5. MAX3766 EV Kit PC Board Layout—Ground Plane
1.0"
Figure 4. MAX3766 EV Kit PC Board Layout—Component Side
1.0"
1.0"
Evaluates: MAX3766
MAX3766 Evaluation Kit
_______________________________________________________________________________________ 7
Figure 6. MAX3766 EV Kit PC Board Layout—Power Layer Figure 7. MAX3766 EV Kit PC Board Layout—Solder Side
1.0" 1.0"
Evaluates: MAX3766
MAX3766 Evaluation Kit
NOTES
Maxim makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Maxim assume any lia-
bility 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.
8
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
