MAIMAN ELECTRONICS SF6040 User manual

v2.0.4 ‒ 2020
SF6040
Laser diode driver
Datasheet &
User Manual
Before powering on your driver, read this manual thoroughly.
If you have any doubt or suggestion, please do not hesitate to contact us!
Maiman Electronics
e-mail: [email protected]
web site: www.maimanelectronics.com

v2.0.4 ‒ 2020
v2.0.3:
Added paragraphs «Overall dimensions and weight» and «Functional schemes»
v2.0.4:
Paragraph «Warranty», error-triggered fall-time values (Paragraph «Electrical characteristics»),
examples of digital commands, and correction in paragraphs «how to get started»and «Digital control
description (extended)» was added.

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Table of content
1. Features ............................................................................................................................................... 3
2. Applications.......................................................................................................................................... 3
3. Description........................................................................................................................................... 3
4. Package set .......................................................................................................................................... 3
5. Overall dimensions and weight ........................................................................................................... 3
6. Absolute maximum ratings.................................................................................................................. 3
7. Recommended operating conditions .................................................................................................. 4
8. Power supply requirements................................................................................................................. 4
9. Electrical characteristics ...................................................................................................................... 4
10. Typical Performance Characteristics ................................................................................................... 6
11. Functional schemes ............................................................................................................................. 7
12. Pin and terminal functions................................................................................................................... 8
13. Analogue control description ............................................................................................................ 10
14. How to get started ............................................................................................................................. 11
15. Cooling ............................................................................................................................................... 11
16. Internal protections ........................................................................................................................... 11
17. Software.............................................................................................................................................11
18. Digital control description ................................................................................................................. 11
19. Digital control description (extended)............................................................................................... 16
20. Mechanical dimensions ..................................................................................................................... 19
21. Warranty ............................................................................................................................................19

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1. Features
Low current ripple
No need to adjust voltage
Soft-start
Adjustable overcurrent limit
Thermal warning and shutdown
Reverse current protection
Crowbar circuit protection
Universal controls
NTC thermistor input
Own software
2. Applications
Supplying laser diodes, bars and arrays
Supplying high power LED arrays
3. Description
The SF6040 is a non-isolated DC/DC SMPS
(POL) with constant current output. Driver
produces high stability and low ripple
current. Protection features include an over
current protection with adjustable limit, soft-
start, thermal warning and shutdown,
reverse current protection and crowbar
circuit protection. This means the SF6040 can
safely drive nonlinear and current quality
sensitive loads like laser diodes and LEDs.
The driver can be controlled by analogue
or digital signals.
SF6040 is available in thermal enhanced
quarter-brick package with aluminum base
plate to aid thermal dissipation. Driver can be
mounted on any thermal conductive surface
enough to dissipate driver losses.
4. Package set
Driver –1 pcs
50 cm ribbon cable with one 8-pin connector –1 pcs
50 cm ribbon cable with one 14-pin connector –1 pcs
Datasheet & User Manual –1 pcs
5. Overall dimensions and weight
The driver has overall dimensions of 57.9 x 36.8 x 21 mm and a weight of 50 g.
6. Absolute maximum ratings*
MIN
MAX
UNIT
Vin+ to Vin-
-0.3
60
V
Operating temperature
-40
50
°C
Analogue control pins to GND
-0.3
5.5
V
RS-232 RXD to GND
-25
25
V
RS-232 TXD to GND
-13.2
13.2
V
UART RXD to GND
-0.3
5.5
V
UART TXD to GND
-0.3
5.5
V
*Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device.
These are stress ratings only, which do not imply functional operation of the device at these or any other
conditions beyond those indicated under recommended operating conditions. Exposure to absolute-maximum-
rated conditions for extended periods may affect device reliability.

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7. Recommended operating conditions
MIN
MAX
UNIT
Input voltage (Vin)
12
55
V
Operating temperature
-10
40
°C
Analogue control pins to GND
0
5
V
RS-232 RXD to GND
-12
12
V
RS-232 TXD to GND
-12
12
V
UART RXD to GND
0
5
V
UART TXD to GND
0
5
V
8. Power supply requirements
The driver requires a DC power supply with line regulation ± 1%. The power supply must be able to
cover the driver output power and losses. The power supply voltage must be at least 27% higher than
the voltage drop of your laser diode. Recommended power supply: Mean well SE-600-48.
ATTENTION! Do not use any relay between power supply and driver. When using a relay, voltage surges
may occur and driver may fail.
9. Electrical characteristics
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
OUTPUT
Output voltage (Vout)
5
0.73*Vin
V
Output current (Iout)
0
10
A
Current ripple
15
25
mA
Pulse rate (F)
QCW-mode
0.1
100
Hz
Pulse duration
Set by RS-232 or UART
2
1/F - 2
5000
ms
Set by analogue pin
0.5
1/F
Rise time (Soft-start time)
Iout = 10A
60
70
100
us
Iout = 5A
60
80
100
us
Fall-time (Stop time)
20
60
80
us
Error-triggered fall-time (Stop time)
15
45
us
Output capacitance
13.2
uF
INPUT
Vin quiescent current
Vin = 48V, no AUX load
10
20
30
mA
Input capacitance
17.6
uF
CONTROLS
Enable pin low threshold
1
V
Enable pin high threshold
2.3
V
Interlock pin threshold
1
V
Interlock pin pull-up resistance
10
kΩ
Current set pin voltage vs. output
current
2
A/V
Current set step
Set by RS-232 or UART
0.01
A
Current set accuracy
1A < Iout < 7A
+/- 5
%
7A < Iout < 10A
+/- 1
%
Current set calibration
- 5
+ 5
%

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AUX SUPPLY
+/- 15V accuracy
+/- 2
%
+/- 15V output current
20
30
mA
5V accuracy
+/- 1.5
%
5V output current
200
300
mA
INTERNAL MEASURMENTS
Internal measurements accuracy
+/-2
%
Current monitor pin voltage vs.
output current
2
A/V
Voltage monitor pin voltage vs.
output voltage
5
V/V
External sensor temperature
NTC 10k
-10
150
°C
POWER DISSIPATION
Driver losses
Vin = 55V, Iout = 10A
10
13
15
W
PROTECTIONS
Crowbar clamp resistance
7.4
9.4
mΩ
Crowbar clamp response time
100
200
ns
Over-temperature warning
threshold temp
60
°C
Over-temperature warning
hysteresis
2
°C
Over-temperature shut down
threshold temp
80
°C
Over-temperature shut down
hysteresis
22
°C

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10. Typical Performance Characteristics
Figure 1 –Power dissipation vs. output current at full load
Figure 2 –Efficiency vs. output current at full load
2A/div
50us/div
Figure 3 –Typical start up sequence
Figure 4 –Typical stop sequence

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11. Functional schemes
Analogue interface
Figure 5 –Analog interface functional scheme
Power unit
Figure 6 –Power unit functional scheme

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12. Pin and terminal functions
Please, note polarity!
Never ground any lead of the output,
this may cause permanent damage to the laser diode and the driver!
Never use any grounded probes (e.g. from the oscilloscope) at the output!
Control pins are not isolated!
Terminals
Please, pay attention to the markings!
Terminal
Description
Vin+
Connect to the positive terminal of
the power supply.
Please, note polarity!
Vin-
Connect to the negative terminal of
the power supply.
Please, note polarity!
LD+
Connect to the laser diode anode.
Please note polarity!
Grounding this terminal may cause
permanent damage to the driver.
LD-
Connect to the laser diode cathode.
Please note polarity!
Grounding this terminal may cause
permanent damage to the laser
diode.
Controls
№
Description
1
Analogue control connector
2
Current limit adjustment
potentiometer (adjustment from
zero to maximum occurs in 12 turns)
3
Digital control connector

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Digital control connector
Wurth WR-MM 6901 5700 08 72 or TE Connectivity 215083-8
Pin
Description
1
UART RXD
2
RS-232 RXD
3
UART ТXD
4
RS-232 TXD
5
+5V auxiliary (duplicates pin 4 of analogue
control connector)
6
Interlock (duplicates pin 5 of analogue control
connector)
7
Crowbar status (duplicates pin 3 of analogue
control connector)
8
GND (connected to Vin- terminal)
Analogue control connector
Wurth WR-MM 6901 5700 14 72 or TE Connectivity 1-215083-4
PIN
I/O
Name
Description
1
I
Enable
High = operates; Low = stop.
Internally pulled down. TTL or CMOS signals only.
2
GND
Connected to Vin- terminal.
3
O
Crowbar status
High = fault; Low = normal operation.
Internally pulled down.
4
+5V
Auxiliary +5V power supply.
Up to 200mA output current capability.
5
I
Interlock
Open = locked; Low = operates.
Internally pulled up.
6
O
Over-temperature
warning
High = t°> 60°C; Low = t°< 58°C.
Internally pulled down.
7
GND
Connected to Vin- terminal.
8
-15V
Auxiliary -15V power supply.
Up to 20mA output current capability.
9
O
Voltage monitor
0-8V = 0-40V at the output.
10
+15V
Auxiliary +15V power supply.
Up to 20mA output current capability.
11
O
Current monitor
0-5V = 0-10А at the output.
12
GND
Connected to Vin- terminal.
13
I
Current set
0-5V = 0-10А at the output.
14
NTC Interlock
Connect NTC thermistor 10k between this pin and GND.

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13. Analogue control description
Enable
The enable pin is active high 3.3V and 5V compatible logic input. Driver operates when enable pin
is high. To ensure correct start-up without overshoot, the soft-start sequence initiates when the enable
pin becomes high.
The enable pin can be used for QCW operation. The output may be pulsed by applying a TTL
square signal to enable pin.
Crowbar status
Crowbar status pin reports the status of the protection shorting crowbar clamp across the output.
The crowbar will short the output while over-current shutdown and over-temperature shutdown.
While the protection shutdown the enable pin is ignored. Disconnect the driver from power to reset
the protection status.
Interlock
The Interlock pin must be connected to GND in order for output current to be delivered. It can be
used for external interlock e.g. door or over-temperature switches.
Over temperature warning
When the temperature of driver PCB exceeds 60°C the over-temperature warning will go high to
indicate driver is in danger of shutting down due to over-temperature condition. When temperature of
driver PCB exceeds 80°C, the driver will stop. The driver can be restarted when the temperature drops
to 58°C.
Voltage monitor
The output voltage of the driver can be monitored by voltage monitor. 0-8V = 0-40V with +/-2%
accuracy. The voltage is measured between LD+ and LD- terminals.
Current monitor
The output current of the driver can be monitored by current monitor. 0-5V = 0-10А with +/-2%
accuracy.
Current set
The driver output current is set by applying an analog signal to the current set pin. 0-5V = 0-10А.
The current set pin can be used for analogue modulation by applying sign, square or ramp signal
with the DC component. Analogue modulation amplitude depends on frequency. Please, control the
output current while using this feature.
If you use arbitrary/function generator or lab PS for current set, make sure it is in High Z mode. Please,
control the current set and current monitor pin voltages while getting started.
NTC Interlock
Thermistor connection. Allows you to measure the temperature of a laser or other devices. The
measurement result is readable by the digital interface. Set upper and lower limits of the temperature
at the outlet of which driver operation is blocked. When the temperature returns to the specified
range, the driver operation resumes.

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14. How to get started
1. Unpack your driver;
2. Connect a dummy load (e.g. a Schottky diode) to the LD- and LD+ terminals. Please note
polarity;
3. Connect the controls (analogue and/or digital);
4. Connect the power supply. Please note polarity;
5. Rotate the current limit potentiometer clockwise several times;
6. Turn on the power supply;
7. Set the current equal to the desired current limit threshold;
8. Enable the driver;
9. Rotate the potentiometer counterclockwise slowly while the crowbar status pin becomes high;
10. Restart the power supply to reset protection;
11. Make sure the over-current protection limit is set right;
12. Make sure that all controls are working;
13. Turn off the power supply and disconnect a dummy load;
14. Connect the laser diode to the LD- and LD+ terminals. Please note polarity.
15. Cooling
The driver produces up to 15W of losses. Thus the base plate has to be mounted on a
thermal conduction surface to ensure proper operation and prevent an over-temperature
shutdown. If the conduction cooling is not enough an additional cooling may be achieved by
placing the driver into the airflow of a fan.
16. Internal protections
Several security features protect the laser diode and driver from damage. Reverse diode
protects the laser diode from reverse currents. In case of an over-current or an over temperature
condition, the control logic disables the driver and the output shorts by a crowbar clamp. A soft-
start mechanism slowly raises the current at startup to protect the laser diode against current
overshooting.
17. Software
We offer own software to control driver. You can find it at maimanelectronics.com in the
downloads section of the product page. Or contact us at [email protected].
18. Digital control description
When the input voltage applied the driver is always in “analogue current set, external enable and
allowing interlock” state. Any other state should be set any time after powering the driver if needed.
Default serial port settings:
Baud rate
Data bits
Stop bits
Parity
Flow control
115200
8
1
none
none

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Data exchange between the driver and the PC is only initiated by the PC. All commands are
sent in plain text format. All commands are sent with prefix. Number of command follows the
prefix without any symbols. If there is the value after the command they separates with “space”
symbol. The command ends with “carriage return” symbol.
The format of the command to set the value (P-type);
Number of byte
Value
Comment
1
P (50h)
Set prefix
2-5
Number of the parameter
Hex-number of the parameter. For
example, 0100h
6
‘space’ symbol (20h)
7-10
New value of the parameter
Hex-value of the parameter. For example,
0000h
11
‘return carriage’ symbol<CR> (0Dh)
End of the command
The device does not respond to P-type commands by default. (see section “the protocol
extension”)
You can request the value of parameter by the J-type command. The device will return a
value of requested parameter.
The format of the command to get the value (J-type)
Number of byte
Value
Comment
1
J (4Ah)
Request prefix
2-5
Number of the parameter
Hex-number of the parameter. For
example, 0100h
6
‘return carriage’ symbol<CR> (0Dh)
End of the command
The format of the response
Number of byte
Value
Comment
1
K (4Bh)
Response prefix
2-5
Number of the parameter
Hex-number of the requested parameter
6
‘space’ symbol (20h)
7-10
Returned value of the parameter
Hex-value of the parameter
11
‘return carriage’ symbol<CR> (0Dh)
End of the command
If the device could not recognize a command, it returns an error message with error code.
The format and codes of errors
Error (returned
command)
Reasons (one or few)
E0000
1) Internal buffer of device is overflowed.
2) Cannot find <CR> (0x0D) or\and <LF> (0x0A).
3) Format of command is invalid.
E0001
1) Unknown command (it does not P- or J-type command).
2) The device failed to correctly interpret a command.
E0002
The CRC of received command (see section “the protocol extension”).
K0000 0000
Request or set the parameter that does not exist.

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Available parameters and its description
Action
R/W
HEX-
number of
parameters
Frequency
(0.1 Hz)
Value
R/W
0100
Minimum
R
0101
Maximum
R
0102
Duration
(0.1 ms)
Value
R/W
0200
Minimum
R
0201
Maximum
R
0202
Current
(0.01 A)
Value
R/W
0300
Minimum
R
0301
Maximum
R
0302
Measured value (0.1A)
R
0307
Current set calibration
(0.01%)1
Value
R/W
030E
Voltage (0.1 V)
Measured value
R
0407
State of the device
Start (Enable)
0008h
W
0700
Stop (Disable)
0010h
Internal current set
0020h
External current set
0040h
External Enable
0200h
Internal Enable
0400h
Allow Interlock
1000h
Deny Interlock
2000h
Deny NTC Interlock
4000h
Allow NTC Interlock
8000h
State of the device (bit
mask)
0 bit
1 –Device is powered on
(always = 1)
R
0700
1st bit
0 –Stopped; 1 –Started
2nd bit
Current set:
0 –External; 1 –Internal
4th bit
Enable:
0 –External; 1 –Internal
6th bit
External NTC Interlock:
0 –Allowed; 1 –Denied
7th bit
Interlock:
0 –Allowed; 1 –Denied
Serial number
Return the hex-value of the serial number
R
0701
1
Default –100.00% (2710h), calibration range is from 95.00% (251Ch) to 105.00% (2904h).

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Device model and
version ID
Return identification number
R
0702
Information
about parameters
that you can
change (bit mask)
0 bit
1 –the device supports
this option
R
0703
1st bit
Frequency
2nd bit
Duration
3rd bit
Current
Lock status (bit
mask)*
0 bit
Reserve
R
0800
1st bit
Interlock
3rd bit
Over current
4th bit
Overheat (warning)
5th bit
External NTC Interlock
NTC sensor
temperature
(0.1°)
Lower limit
R/W
0A05
Upper limit
R/W
0A06
Measured value
R
0AE4
B25/100
R/W
0B0E
PCB temperature
(0.1°)
Measured value
R
0AF4
*If temperature of the device reaches the over temperature warning threshold the overheat flag will be set. If
the device is in over temperature protection state, then it will be set overheat and over current flags together.
Examples
1) For the current value parameter, 0300:
To request value, send the following command:
"J0300" in text or "4a 30 33 30 30 0d" in hex.
Answer will be:
"4b 30 33 30 30 20 30 33 45 38 0d" in hex, "K0300 03E8" in text, 03E8h > 1000 in dec > 10.00 A.
To set new value, for example, 8.00 A (0320 in hex), send the following command:
"P0300 0320" in text or "50 30 33 30 30 20 30 33 32 30 0d" in hex.
2) For the state of the device, 0700:
To request value, send the following command:
"J0700" in text or "4a 30 37 30 30 0d" in hex.
Answer will be:
"4b 30 37 30 30 20 30 30 44 35 0d" in hex, "K0700 00D5" in text, 00D5h > 11010101 in bin >
Device is powered on, stopped, internal current set, internal enable, denied external NTC
Interlock, denied Interlock.
To set new state, for example, allow Interlock, send the following command:
"P0700 1000" in text, "50 30 37 30 30 20 31 30 30 30 0d" in hex.
3) Errors:
If a command with the wrong parameter number was sent, answer will be "K0000 0000"
("4b 30 30 30 30 20 30 30 30 30 0d").
If a command with the wrong format was sent, answer will be an error "E0001"
("45 30 30 30 31 0d").

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Fig. 7 –Screenshot from the Termite terminal with commands and answers
The maximum duration depends on the set value of the frequency. When you change
frequency, a new value of the maximum duration is compute automatically. The duration of pulse
cannot be less than 2 ms and more than period of frequency minus 2 ms. For low frequencies the
duration cannot be more than 5000 ms.
Set the zero frequency to switch the device into CW mode or set not zero frequency value to
switch the device into QCW (long pulses) mode. If you try to set a value more or less than limits,
then the value will be rounded to limit. Any attempts to set a new state of the device, except
“start”, forcibly switch the device to the state “stop”. Some states of the device are mutually
exclusive, for example, if you set “Ext. Enable”, then you will not be able to set the state “start”. If
you send “start” and “stop” commands to each other, the device will save all parameters in the
internal memory. The saving process lasts about 300 ms. In this time the device does not respond
to any actions. The device is able to save the next parameters in the internal memory:
Frequency with limits;
Duration with limits;
Current with limits and calibration;
Temperature limits and B25/100;
Settings of the RS protocol extension (see section «the protocol extension»).

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19. Digital control description (extended)
WARNING! Extended protocol recommend for advanced users only. In addition, it might be used for
integration of the device with other devices.
Use the parameter number 0704h for configure the extended protocol. In extended
protocol, you can enable and disable the next options: checksum (CRC 8-bit CCITT), return a new
value of parameter after P-type commands, change baud-rate, change protocol-mode (text-plain
or binary).
The description of the protocol extension command
Action
R\W
HEX-number of
parameters
Information about the
extended protocol
0 bit
1 –the device supports
this option
R
0704
1st bit
Checksum (1 –on, 0 –off)
2nd bit
Return a new value for P-
type commands (1 –on, 0
–off)
3-5 bits
Baud - rate
0 –2400
1 –9600
2 –10417
3 –19200
4 –57600
5 –115200 (default)
6th bit
Data exchange mode (1 –
binary, 0 –text-plain)
Configuring of the
extended protocol
On checksum (CS)
0002h2
W
0704
Off checksum
0004h2
Return a new value
for P-type commands
0008h2
Do not return answer
for P-type commands
0010h2
Set new baud-
rate(baud)3
0100h –2400
0120h –9600
0140h –10417
0160h –19200
0180h –57600
01A0h –115200
Binary mode on4
0200h
Text-plain mode on
0400h
2
In binary mode the specified commands are ignored by the device
3
Here are binary numbers
4
For more information, see section “binary mode”

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Text-plain mode
All commands in text-plain mode should be in ASCII.
WARNING! If you enable the checksum it will change format of commands. After <CR> symbol
you will be write 2 bytes of checksum and last byte will be <LF> (0Ah –“new line” symbol). Checksum is
computed for all bytes of command before checksum bytes (including<CR> symbol).
All answers of the device will also contain a checksum, including K-type and E-type answers.
Checksum is computed by CRC-CCITT-8 algorithm. This is the main difference between the format
of commands for the extended protocol and standard protocol.
The format of commands for enabled checksum
Number of byte
Value
Comment
1
P,J,K,E
Type of command
2-5
Number of parameter
Hex-number of value
6
‘space’ symbol (20h)
(does not use for J and E-type commands)
7-10
New value of the parameter
Hex-value of parameter (does not use for J and
E-type commands)
11
‘return carriage’ symbol<CR>
(0Dh)
End of value
12-13
Checksum
CRC checksum of the first 11 bytes (for J and E-
type commands checksum is computed for the
first 6 bytes), including <CR> symbol.
14
‘new line’ symbol<LF> (0Ah)
End of command
Possible problems
1. The device waiting for symbol <LF>. If <LF> symbol does not received and buffer is overflowed,
then all symbols after overload will be processed as a new command. The device returns an
error. In this case, it is recommended to send the <LF> symbol. The device will generate an
error and clear the buffer for the next command.
2. All symbols after the <LF> symbol will be processed as a new command.

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Binary mode
The binary mode has a significant difference. In this mode, data are exchanged in binary
form. Length of any type of command is 8 bytes! In this mode, next options are always enable and
you cannot disable it: return a new value of parameter for P-type commands and checksum. The
format of binary mode commands is represented in table 8.
The format of binary mode commands
Number of byte
Value
Comment
1
Type of command
50h (P - ascii) –Set a new value of parameter
4Ah (J - ascii) –Get a value of parameter
4Bh (K - ascii) –Answer of the device
45h (E - ascii) –Error
2-3
Number of parameter
Hex-number of parameter
4-5
Value of parameter
Hex-value of parameter. This value is STRICTLY
REQUIRED in the binary mode. If this value
does not make sense, it will be returned as
0000 (K or E-type commands) or you should set
it field to any value (for P or J-type commands).
6
‘return carriage’ symbol <CR>
(0Dh)
End of value
7
Checksum
CRC checksum of the first 11 bytes (for J and E-
type commands checksum is computed for the
first 6 bytes), including <CR> symbol.
8
‘new line’ symbol <LF> (0Ah)
End of command

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20. Mechanical dimensions
All dimensions are in millimeters. You can download the 3D-model of the driver at
maimanelectronics.com in the downloads section of the product page.
21. Warranty
In compliance with the provisions of Conditions limited warranty the Buyer has the right to
guarantee during the one year period. The warranty period comes into effect from the shipping date.
The warranty only concerns products that are applied according requirements and for the
applications specified in the manual for the product. If you want to use the products for other
applications, contact us by e-mail: [email protected]. This warranty does not apply to
damage due to incorrect use, abnormal use, or use in violation of product manual.
See the full warranty conditions on www.maimanelectronics.com/warranty.