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15

WLD SERIES LASER DIODE DRIVERS

UTILIZING V

SET

 (PIN 2)

Pin 2 on the WLD33ND, V

SET

, can be used for externally 

defining the setpoint, or as a modulation input. 

Figure 12

 

illustrates a typical configuration of the voltage input.

!

The available voltage range for V

SET

 is 0-2 V. 

Connecting voltages outside this range can 

result  in  damage  to  the  WLD33ND  or  the 

laser diode.

GND

7

WLD33ND

2

V

SET

2 k

1 k

DC BIAS

TRIMPOT

2.5 V

Bandgap

Voltage

Reference

V

PIN2

V

DD

OR

OR

+

Figure 12.  

Configuring the voltage input for either a fixed 

(left) or a modulated (right) voltage setpoint.

For a given voltage supplied to V

SET

, either the laser 

diode current will change (Constant Current mode), or the 

photodiode current will change (Constant Power mode).

Constant Current Mode:

 

The resulting laser diode current is given by 

Equation

 

(9)

.  

I

LD

=

V

PIN2

(9)

 

2·R

SENSE

Constant Power Mode:

 

The resulting photodiode current is given by 

Equation

 

(10)

.

I

PD

=

V

PIN2

(10)

 

2·R

PD

MONITORING THE LASER DIODE CURRENT 
(PIN 3)

Pin 3 (IMON) produces a voltage proportional to the current 

flowing through the laser diode. 

Equation

 

(11)

 provides 

transfer function for converting the voltage output of Pin 3 to 

the amount of forward current.

I

LD

=

V

PIN3

(11)

 

2·R

SENSE

MONITORING THE PHOTODIODE CURRENT

The  photodiode  current  is  measured  differently  in 

Constant Current and Constant Power mode, due to the 

configurational differences between the modes.

Constant Current Mode:

In Constant Current mode, the photodiode current is 

measured directly across R

PD

Equation

 

(12)

 provides 

a transfer function for converting this voltage into the 

corresponding current through the monitor photodiode.

I

PD

=

V

RPD

(12)

 

R

PD

Constant Power Mode:

In Constant Power mode, the photodiode current is 

measured using Pin 4 (PMON). 

Equation

 

(13)

 provides a 

transfer function for converting this voltage to the amount of 

current flowing through the monitor photodiode.

I

PD

=

V

PIN4

(13)

 

2·R

PD

Use the online WLD Circuit Calculator to automatically determine 

values for external components.

www.teamwavelength.com/support/design-tools/wld-calculator/

Содержание WLD33ND

Страница 1: ...oard switches connectors and trimpots make the configuration and operation simple Input and output cables are also included with the WLD33ND EV The WLD33ND is excellent for VCSELs electro optical equi...

Страница 2: ...n tools wld calculator 1 2 3 4 5 6 7 14 13 12 11 10 9 8 TOP VIEW SHD VSET IMON PMON MODE LIM GND VDD PD PD OUTA RS OUTB RS Shutdown Laser Diode Output Current Setpoint Voltage Input Laser Diode Curren...

Страница 3: ...AD VS 2 5 1 ILIM and the power rating of the resistor is found by PRLOAD I2 LIM RLOAD 2 For example if VS is 12 V and the current limit is 2 A then RLOAD needs to be 4 75 with a power rating of 19 W T...

Страница 4: ...nnected between this pin and Pin 7 GND limits the maximum amount of forward current through the laser diode See page 11 for more information 7 GND Power Supply Ground Connect the VDD power supply grou...

Страница 5: ...or 2 mA POWER SELECT Separate or tied power supplies Configures the WLD33ND EV to either use separate VS and VDD supplies or to tie the VS and VDD connections for single supply operation VSET SOURCE...

Страница 6: ...se Time 100 ns ILD Full Scale Fall Time 200 ns ILD Full Scale Bandwidth 2 2 MHz CC Sine Wave 2A Slow Start Delay Time 0 24 sec Slow Start Ramp Time 0 01 sec Leakage Current 3 0 mA Noise Ripple 22 26 1...

Страница 7: ...TAMBIENT 25 C Max Internal Power Dissipation Heatsink Fan 9 9 10 W TAMBIENT 25 C Heatspreader Temperature Rise TAMBIENT 25 C 30 C W No heatsink washer fan 21 5 C W With WHS302 Heatsink WTW002 Thermal...

Страница 8: ...erence between the two signals It may be useful to remember that you do not directly set the drive current setpoint instead you adjust a voltage signal that represents the output current The voltage a...

Страница 9: ...1 1 times the maximum laser diode current plus 150 250 mA for the electronics The HB offers low voltage operation for use with a Lithium ion battery or other low voltage power supplies PREVENT DAMAGE...

Страница 10: ...NSE CC 1 00 4 ILDMAX ILDMAX CONSTANT POWER RSENSE CONSTANT CURRENT RSENSE 50 mA 25 00 20 00 125 mA 10 00 8 00 250 mA 5 00 4 00 500 mA 2 50 2 00 1 25 A 1 00 0 80 2 2 A 0 57 0 45 WLD33ND 3A WLD33ND 3L O...

Страница 11: ...y calculate the value of RLIM use Equation 7 and Table 4 for the values of and RLIM ILDLIM RSENSE 1 7 1 ILDLIM RSENSE 1 LASER DIODE TYPE MODE Type A B CC 282 2 85 Type A B CP 350 3 35 Type C CC 290 2...

Страница 12: ...connections TYPE A B TYPE C GND GND RPD RPD VDD OR OR CONSTANT CURRENT TYPE A B TYPE C PD PD GND GND VDD VDD PD PD 7 7 13 13 12 12 14 14 OR PIN 11 WLD33ND WLD33ND OR PIN 10 RPD RPD CONSTANT POWER Figu...

Страница 13: ...ured for Constant Current operation Constant Power 1 2 3 4 5 6 7 14 13 12 11 10 9 8 WLD33ND LASER DIODE DRIVER VDD RPD RLIM 1 TIE GROUND CONNECTIONS DIRECTLY TO PIN 7 RSENSE ENABLE DISABLE IMON PMON 0...

Страница 14: ...A 438 m 5 01 Figure 10 Type C laser configured for Constant Current operation Constant Power 1 2 3 4 5 6 7 14 13 12 11 10 9 8 WLD33ND LASER DIODE DRIVER RPD RLIM 1 TIE GROUND CONNECTIONS DIRECTLY TO P...

Страница 15: ...IPD VPIN2 10 2 RPD MONITORING THE LASER DIODE CURRENT PIN 3 Pin 3 IMON produces a voltage proportional to the current flowing through the laser diode Equation 11 provides a transfer function for conv...

Страница 16: ...ELECTRONICS WLD33ND EV ONLY 0N FAN PMON SET 2 5 PDM CP COM LIM WITH ENABLE VS IMON OFF C USE 1 Index Marker WLD 33ND Sockets Mode Switch Output Current Enable Disable Switch Fan Power Input Cable Conn...

Страница 17: ...o available options are the 200 mA or the 2 A position PD RANGE Jumper Set the PD RANGE jumper on the bottom of the WLD33ND EV to either the 200 A or the 2 mA range depending on the specifications of...

Страница 18: ...efer to the WHS302 WTW002 WXC303 and or the WXC304 datasheets for assembly instructions Fan Connections Connect the fan leads to the and fan power positions on the terminal block and secure with a sma...

Страница 19: ...ast twelve turns counter clockwise OFF Adjust the LIM trimpot at least twelve turns clockwise ON D Apply power to the WLD33ND EV and enable the output current by switching the enable switch to the ON...

Страница 20: ...nt controls the output of the WLD33ND The setpoint voltage can be adjusted using the onboard SET trimpot applying an external setpoint voltage or by summing the two signals The VSET SOURCE jumper must...

Страница 21: ...the onboard toggle switch The output is enabled when the green ON LED indicator is lit see Figure 13 You can also remotely enable the WLD33ND by connecting a control signal to a via See Figure 19 Thi...

Страница 22: ...t maximum output current at this supply voltage is 170 mA 200 mA range or 1 7 A 2 A range BANDWIDTH OPTIMIZATION WITH THE WLD33ND EV EVALUATION BOARD To improve bandwidth shorten the cables Expect 1 8...

Страница 23: ...ects the VDROP line On the X axis mark value of VS Extend a diagonal line from VS to the intersection of the VDROP and IMAX lines this is the Load Line If the Load Line crosses the Safe Operating Area...

Страница 24: ...E VDD PDM VA VA R4 332 VA VA R17 499 R16 4 99K R23 1 00M R24 1 00M R22 1 00M R14 1 00M R7 1 00K R9 1 00K R8 1 00K R10 1 00K R6 1 00K 2 3 1 8 4 U4A AD8032 5 6 7 8 4 U4B AD8032 2 3 1 8 4 U2A AD8032 5 6...

Страница 25: ...hin the Safe Operating Area if VDD is increased Laser does not reach desired output in Constant Power mode Photodiode feedback current is out of range for the WLD Refer to the laser diode datasheet to...

Страница 26: ...an be installed in a socket soldered to a PCB Two 7 pin SIP sockets are required Wavelength recommends Sullins PPPC071LFBN RC Socket WEIGHTS WLD33ND 0 6 oz WHS302 Heatsink 0 5 oz WXC 303 4 0 3 oz PIN...

Страница 27: ...Molex 43645 00400 57 2 2 25 39 6 1 56 11 2 0 44 28 7 1 13 1 875 47 63 4 8 0 19 2 25 57 1 2 38 60 5 1 875 47 63 2 25 57 1 1 3 0 05 4 4 0 17 2 48 62 9 4 0 0 156 4 8 0 19 The WLD33ND connects to the eva...

Страница 28: ...UE PGND 2 ORANGE VS 3 RED VDD 4 BLACK COM 5 WHITE VM1 6 GREEN VM2 CABLING SPECIFICATIONS These cables are included with the WLD56ND EV Evaluation Board WTC3293 00101 INPUT CABLE MOLEX 43645 0400 MICRO...

Страница 29: ...er are expressly prohibited from reverse engineering decompiling or disassembling this product NOTICE The information contained in this document is subject to change without notice Wavelength will not...

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