LDTC/ Combine the drive power of the WLD with the temperature stability of the WTC GENERAL DESCRIPTION: The LDTC / combines a. Amp laser driver and. Amp temperature controller on one small board. Available as an open frame or in a chassis mount enclosure. The WTC will control temperature using thermistors, RTDs, or linear temperature sensors such as the LM or the AD0. Adjust temperature using the onboard trim pot or a remote voltage input from a panel mount potentiometer, DAC, or other voltage source. A default temperature set point confi guration provides fault tolerance and avoids accidental damage to system components. Adjustable trim pots confi gure heat and cool current limits. The heart of the laser driver section is the WLD. Amp Laser Driver. It maintains precision laser diode current (Constant Current mode) or stable photodiode current (Constant Power mode) using electronics compatible with A/B Type lasers. Ideal for integrated laser driver or LED packages that include termperature control, often utilized in medical diagnostic equipment, remote sensing, analytical instrumentation, military and communications applications. FEATURES, LDTC/: Small package size Single supply operation possible Cost Effective e March, 00 FEATURES, Laser Diode Driver: Default current range is.a. Custom ranges, from ma up, are easily confi gured Slow start laser diode protection Constant Current or Constant Power modes Compatible with A or B type laser diodes Adjustable laser diode current limit Remote TTL Shutdown / Interlock FEATURES, Temperature Controller: Drive up to.a of TEC current Set temp using D/A - includes default to Volt to avoid drive when D/A is turned off or signal is lost Ultra-stable PI control loop Separate Heat & Cool current limits Single power supply operation possible Pb RoHS Compliant LDTC/ Laser Diode Driver and Temperature Controller Figure Top View Pin Layout and Descriptions D POWER ON TOP VIEW ExtTset Vset PDset CC CP COM SEN- SEN TEC- TEC COM LDA PDC PDA LDC GND VS J J 0 S R SENSE 0 J COM R TC SET SET T M ACT T MON LD I MON LD P MON COM R LDSET COM LD SHD PD MON COM J Fan Power Tset LIMA LIMB ILIM ISET 00 LDTC/-0000-A Rev E R R R R R D ON LD ENABLE OFF LD ENABLE TOGGLE SWITCH
BLOCK DIAGRAM Schematic for WLD connections Remote Enable OFF S R 0K ON SHD PAGE LDTC/ VSET GTMCKE IMON R.00K % PMON MODE D LED LIM C 0.UF 0V GND C.UF V U RS- PD- PD A 0 0.0.W R R 0.0.W B RS WLD CCW CW Ext Vset VR -- LM00AIM-. LDC PDA PDC LDA R.00K R.00K JP HEADER Shown in CC S EG IMON PMON LIM R W 00 C.UF V R 0 UA UB 0 UC Common TEC TEC- Sensor Sensor- Common J 0 CON0 TEC TEC- Sensor MOD R.00K R 0K C 0.UF R K W UD R.00K R0.00K R.00K R.00K JP HEADER J Fan Power Works with these LASER DIODE TYPES R.00M C 0.UF 0V CCW CW ISET PDMON R.00M R.00M.00M R0 R0 R.K TYPE A TYPE B 00 LDTC/-0000-A Rev E
PAGE LDTC/ VR -- LM00AIM-. R R LIMA LIMB W K K W R Set T.00K U VS VSET GND LIMA OUTB LIMB OUTA 0 Rbias P BIAS 00uA V S WTC SG ACT T I BLOCK DIAGRAM Schematic for WTC connections TEC TEC- Sensor VCC D power CCW CW CCW CW R.00K % R.K R.K VS VS LM0IM-. U VIN.V VCC R.00K GND R K W UB VCC VCC R 00K R 0.0K R.00K % U IN V GND ISL NO COM NC Common PD MON Rem En Common Ext Vset Common PMON IMON ACT T SET T Vset/DAC Common J 0 PDMON Remote Enable Ext Vset CON * PIN & NOT AVAILABLE ON Rev. A OPARU OS PMON IMON R ACT T VS 0.UF C.00M SET T C GND UF V J CON VCC R 0.0K OPAR _ U UA OPARU OS R K % R 0.0K R.K JP HEADER C.UF 0V C.UF V C 0.UF 0V.UF 0V C C.UF 0V CCW CW C0 0.UF 0V C 0.UF 0V 0.UF C R0.K C 0.UF R 0 UB OPARU C 0.UF 0V R.K C 0.UF C 0.UF UA OPARU TSET R.00K 00 LDTC/-0000-A Rev E
ELECTRICAL AND OPERATING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS Operating Temperature, case [] Storage Temperature Weight - with enclosure Weight - open frame WLD Laser Diode Driver Rating Supply Voltage (Voltage on Pin ) Output Current (See SOA Chart) Power Dissipation, T AMBIENT = C SYMBOL VALUE UNIT T OPR T STG LDTC/E LDTC/O SYMBOL V DD I LD P MAX - 0 to - to 0.. VALUE. to. C C oz oz PAGE UNIT Volts DC Amps Watts LDTC/ WTC Temperature Controller Rating Supply Voltage (Voltage on Pin ) Supply Voltage (Voltage on Pin ) Output Current (See SOA Chart) Power Dissipation, T AMBIENT = C (with fan and heat sink per SOA Chart) SYMBOL VALUE UNIT V DD V S I OUT P MAX. to. to ±. Volts DC Volts DC Amps Watts Laser Diode Driver PARAMETER CONSTANT CURRENT CONTROL Long Term Stability, hours CONSTANT POWER CONTROL Long Term Stability, hours OUTPUT Current, peak, see SOA chart Compliance Voltage, Laser Diode Load Rise Time Fall Time Bandwidth Bandwidth Delayed Start Slow Start Ramp Rate POWER SUPPLY Voltage, V DD Current, V DD supply, quiescent INPUT Offset Voltage, initial, Imon Bias Current (based on input Res of op amp) Common Mode Range Common Mode Rejection, Set point Power Supply Rejection THERMAL Heatspreader Temperature Rise Heatspreader Temperature Rise Heatspreader Temperature Rise Pin Solderability Note []. With Revision D of the WLD, an internal thermostat has been added to activate Shutdown (SHD) when the internal temperature exceeds 0 C. The output will be re-enabled after a 0 to 00 msec slow-start once the internal temperature drops below C. 00 TEST CONDITIONS T AMBIENT = C T AMBIENT = C With Heat Sink and Fan Full Temp. Range, I LD =.0 Amps, V I LD = Amps I LD = Amps Constant Current, Sine Wave Constant Power Pin, T AMBIENT = C, V CM = 0V Pin, T AMBIENT = C, V CM = 0V Pin, Full Temperature Range Full Temperature Range Full Temperature Range T AMBIENT = C With WHS0 Heat sink and WTW00 Thermal Washer With WHS0 Heat sink, WTW00 Thermal Washer and. CFM fan Solder temp @0 C LDTC/-0000-A Rev E MIN TYP MAX UNITS 0.0..0 0 0 0. 0.0 0 0. 0. 0.0 0 0 0 0.. 0 0.0. (Depends on PD BW) 0 V DD. ppm % Amps Volts nsec nsec MHz Seconds Seconds Volts ma mv na V db db C/W C/W C/W Sec
ELECTRICAL AND OPERATING SPECIFICATIONS, continued Temperature Controller PARAMETER TEMPERATURE CONTROL Short Term Stability, hour Long Term Stability, hour Control Loop P (Proportional Gain) I (Integrator Time Constant) Setpoint vs. Actual T Accuracy OUTPUT Current, peak, see SOA Chart Compliance Voltage, Pin to Pin Compliance Voltage, Pin to Pin Compliance Voltage, Pin to Pin Compliance Voltage, Pin to Pin Compliance Voltage, Resistive Heater POWER SUPPLY Voltage, Current, supply, quiescent Voltage, Vs Current, Vs supply, quiescent INPUT Offset Voltage, initial Bias Current Offset Current Common Mode Range Common Mode Rejection Power Supply Rejection Input Impedence Input voltage range TSET = C using 0 k thermistor TSET = C using 0 k thermistor TSET = C using 0 k thermistor Full Temp. Range, I OUT = 00 ma Full Temp. Range, I OUT = Amp Full Temp. Range, I OUT =. Amps Full Temp. Range, I OUT =.0 Amps Full Temp. Range, I OUT =.0 Amps Pins and Pins and, T AMBIENT = C Pins and, T AMBIENT = C Pins and, Full Temp. Range Full Temperature Range Full Temperature Range 0.00 0.00 P ±. V S - 0. V S -. V S -. V S -. V S -... 0 0 0 0 GND 0.00 0.00 PI 0 <0.%(Rev B) ±.0 V S - 0. V S -.0 V S -. V S -. V S -. 0 0 0 00 0.00 0.00 ±. 0 00 0 0 - [] - [] PAGE TEST CONDITIONS MIN TYP MAX UNITS C C A/V Sec. Amps Volts Volts Volts Volts Volts ma Volts ma mv na na V db db k Volts LDTC/ [] The bias source has a compliance up to -.0 V. In normal operation this limits the sensor voltage range from 0.V to -.0V. While voltages up to /- V outside this range on the Vset pin will not damage the unit, it will not provide proper control under these conditions. NOTE: Operation higher than V on (i.e. V) requires close evaluation of the SOA curves and current limit settings. Damage to the WLD or WTC will occur if they are operated outside their Safe Operating Area. Contact the factory if you plan to use higher than V. 00 LDTC/-0000-A Rev E
PIN DESCRIPTIONS Connector (J) Pin VS Pin # Name Function (RED) Supply Voltage to Control Electronics and Laser Diode Supply Voltage to Output TEC Drive GND (BLK) Power Supply Ground Connector (J) COM (TAN) Common PD MON LD SHD COM (VLT) R LDSET (YEL) COM LD P M LD I M ACT T M SET T M R TCSET (WHT) PD Monitor in CC mode LD Shutdown / Interlock Common Remote Laser Diode Setpoint/Modulation Input Common Photodiode Monitor LD Current Monitor Actual Temp Monitor Setpoint Monitor 0(GR/BK) Common Remote Temperature Setpoint COM (BLK) Common Connector (J) LDC PDA PDC LDA COM (BLK) (WHT) (BLU) (RED) (GRN) Laser Diode Cathode Photodiode Anode Photodiode Cathode Laser Diode Anode Common TEC (RD/BK) TEC connection TEC- (ORG) TEC - connection SEN SEN- (WT/BK) Temperature Sensor (OR/BK) Temperature Sensor - COM (WHT) (PNK) (GRY) (ORG) (BLU) (BRN) (GRN) 0 (RED) PAGE Connect to V between pins & to power the control electronics and the output drive to the Laser Diode. Use the online Safe Operating Area calculator to make sure maximum internal power dissipation in the WLD is not exceeded - especially when using greater than V. Connect to V between pins & to drive the TEC output stage - Use the online Safe Operating Area calculator to make sure maximum internal power dissipation in the WTC is not exceeded - especially when using greater than V. Connect power supply ground to this pin. Low current GND for monitors, DACs, External VSET, etc. PIN not available on Rev. A Photodiode Monitor in constant current mode PIN not available on Rev. A Float or GND = Enable Laser Diode Current Input >V = Disable Laser Diode Current Low current GND for monitors, DACs, External VSET, etc. Voltage Input range is 0 to V. Transfer function: V R LDSET = I LD * ( R SENSE ) Low current GND for monitors, DACs, External VSET, etc. Monitor the laser diode power. The Photodiode Current Monitor produces a voltage proportional to the current produced by the laser diode monitor photodiode. Monitor the laser diode forward current. The Laser Diode Current Monitor produces a voltage proportional to the current flowing through the laser diode. Monitor the actual voltage produced by the temperature sensor. The voltage produced and transfer function to temperature is determined by the sensor chosen. Monitor the temperature setpoint voltage. The voltage produced and transfer function to temperature is determined by the sensor chosen. Connect a voltage source between Pin (VSET) and Pin (GND) to control the temperature setting remotely. A default value of V (about room temperature with 0k thermistor) will be seen by the WTC if the voltage at this pin drops below 0.V. Low current GND for monitors, DACs, External VSET, etc. Laser diode cathode connection Photodiode anode connection Photodiode cathode connection Laser diode anode connection Low current GND Cooling current fl ows from this pin when using an NTC sensor. Heating current fl ows from this pin when using an NTC sensor. Connect resistive and LM type temperature sensors across Pin and Pin. Connect a 0 k resistor across these pins when using AD0 type temperature sensors. The negative terminal of the AD0 sensor connects to Pin and the positive terminal to Pin () of Connector. AD0 operation requires that be Volts or greater for proper operation. Low current GND for monitors, DACs, External VSET, etc. LDTC/ 00 LDTC/-0000-A Rev E
TYPICAL PERFORMANCE GRAPHS - WLD PAGE Caution: Do not exceed the Maximum Internal Power Dissipation of the WLD or WTC. Safe Operating Area (SOA) tools are provided online to make your design easier. Exceeding the Maximum Internal Power Dissipation voids the warranty. LDTC/ To determine if the operating parameters fall within the SOA of the device, the maximum voltage drop across the driver and the maximum current must be plotted on the SOA curves. These values are used for the example SOA determination for a WLD: V s = Volts } V = Volts Load These values are determined from the specifications of the laser diode, and in the I Load = Amp context of the specific application. Follow these steps:. Determine the maximum voltage drop across the driver, V s -V Load, and mark on the X axis. Example: Volts - Volts = Volts (Point A). Determine the maximum current, I Load, through the driver and mark on the Y axis: Example: Amp (Point B). Draw a horizontal line through Point B across the chart. (Line BB). Draw a vertical line from Point A to the maximum current line indicated by Line BB.. Mark V S on the X axis. (Point C). Draw the Load Line from where the vertical line from point A intersects Line BB down to Point C. Refer to the chart shown below and note that the Load Line is outside the Safe Operating Areas for use with no heatsink () or the heatsink alone (), but is within the Safe Operating Area for use with heatsink and Fan (). An online tool for calculating your load line is at http:///support/calculator/soa/soald.php Graphs assume: C Case B BB LOAD LINE A C 00 LDTC/-0000-A Rev E
TYPICAL PERFORMANCE GRAPHS - WTC PAGE Caution: Do not exceed the Maximum Internal Power Dissipation of the WLD or WTC. Safe Operating Area (SOA) tools are provided online to make your design easier. Exceeding the Maximum Internal Power Dissipation voids the warranty. LDTC/ To determine if the operating parameters fall within the SOA of the device, the maximum voltage drop across the controller and the maximum current must be plotted on the SOA curves. These values are used for the example SOA determination for a WTC: V s = Volts V Load = Volts I Load = Amp Follow these steps:. Determine the maximum voltage drop across the controller,v s -V Load, and mark on the X axis. Example: Volts - Volts = Volts (Point A). Determine the maximum current, I Load, through the controller and mark on the Y axis: Example: amp (Point B). Draw a horizontal line through Point B across the chart. (Line BB). Draw a vertical line from Point A to the maximum current line indicated by Line BB.. Mark Vs on the X axis. (Point C). Draw the Load Line from where the vertical line from point A intersects Line BB down to Point C. Refer to the chart shown below and note that the Load Line is outside the Safe Operating Areas for use with no heatsink () or the heatsink alone (), but is within the Safe Operating Area for use with heatsink and Fan (). An online tool for calculating your load line is at http:///support/calculator/soa/soatc.php. C Case B BB A C Proper heat dissipation from the WLD & WTC is critical to longevity of the LDTC /. The heat spreaders of the WTC and WLD are positioned to use your chassis for heat dissipation. Be sure to add thermally conductive paste to all relevant surfaces that need to dissipate heat. 00 LDTC/-0000-A Rev E
WTC OPERATION Recommended order of setup: WTC confi guration should be addressed fi rst, using a simulation diode load in place until the temperature control section is working properly. After the temperature control section is operating according to preferences, then the laser diode load can be confi gured. Using a simulated diode load until you are comfortable with WLD confi guration and operation is recommended in order to avoid any potential damage to an expensive laser diode. PAGE CAUTION: Operate the LDTC/ with all loads attached - if you short either the LD or TC output connections during setup, current will fl ow and possibly overheat / damage the WLD or WTC. LDTC/. CONFIGURING HEATING AND COOLING CURRENT LIMITS The LDTC/ has two trimpots that independently set the heating and cooling current limits: LIM A & LIM B. These are -turn k trimpots. Full current (. A) is at full CCW position. Table shows the meaning of the trimpots with various sensors and load types. Note that PTC sensors include RTDs, the LM, and the AD0.. WIRE OUTPUT CONNECTION Use Table to determine the connection from the LDTC/ to your thermoelectric or resistive heater. Table Trimpot function vs. Sensor & Load Type Sensor Type Load Type Thermistor Thermoelectric PTC Thermoelectric Thermistor Resistive Heater PTC Resistive Heater LIM A Limits: Cool Current Heat Current OFF = Fully CW Heat Current LIM B Limits: Heat Current Cool Current Heat Current OFF = Fully CW Table Wiring vs. Sensor & Load Type Sensor Type Thermistor PTC Thermistor PTC Load Type Thermoelectric Thermoelectric Resistive Heater Resistive Heater TEC Connector, Pin TEC - Connector, Pin Thermoelectric positive wire Thermoelectric negative wire Thermoelectric negative wire Thermoelectric positive wire Quick Connect: Connect the Resistive Heater to TEC & TEC - (polarity doesn t matter). Adjust the Cooling Current Limit A trimpot to zero - fully CW. Max V Connect: Connect one side of the resistive heater to TEC- and the other side to the voltage source V S. LIM A trimpot setting is then irrelevant. Quick Connect: Connect the Resistive Heater to TEC & TEC - (polarity doesn t matter). Adjust the Cooling Current Limit B trimpot to zero - fully CW. Max V Connect: Connect one side of the resistive heater to TEC- and the other side to the voltage source V S. LIM B trimpot setting is then irrelevant.. CONNECT TEMPERATURE SENSOR The LDTC/ is configured to operate a 0k thermistor with a 00 A bias current. If your application requires a different sensor, please contact Wavelength for details. Wire the thermistor between pins & (SENS & SENS-) on Connector J. Operating without a temperature sensor will drive maximum current through the WTC, potentially damaging it. 00 LDTC/-0000-A Rev E
WTC OPERATION, continued. PROPORTIONAL GAIN AND INTEGRATOR TIME CONSTANT - PI TERMS The LDTC/ is configured to the mid-range positions appropriate for most laser diode loads. To adjust these parameters to optimize the temperature control system time to temperature or stability, contact Wavelength. PAGE 0. TEMPERATURE SETPOINT Wavelength introduces a special setpoint circuit with the LDTC/. An on-board trimpot (TSET) will adjust the voltage from 0.V to.v. Additionally, Pins (R TC SET) & (COM) of Connector J will accept a DAC voltage (from 0. to.v). The new feature - the Failsafe Setpoint will default the setpoint to V (~ C for a 0k thermistor) if the chosen signal (from pot or DAC) falls below 0.V. LDTC/. POWER SUPPLY SELECTION The voltage supply input is common to both the WLD and the WTC. This supply furnishes the voltage to the control electronics of the devices as well as the compliance voltage for the WLD Laser Driver. The supply should be capable of providing at least.0 Amps of current in applications that use a separate VS supply in the temperature control implementation. Temperature control applications that tie and VS together require a current capacity that equals the sum of the maximum TEC or Resistive Heater current, plus the maximum laser diode current, plus approximately 00 ma for the control electronics of the WTC Temperature Controller and the WLD Laser Driver, plus current to an optional fan. Using the maximum potential of the WLD and WTC will not require more than.0 Amps. VS is the voltage that is applied to the TEC or Resistive Heater. This voltage should be high enough to supply the voltage required by the TEC or Resistive Heater plus the compliance required by the WTC. The voltage available to the TEC will be from between 0. to.v lower than VS. To minimize power dissipation in the WTC, keep VS as low as possible. Calculate the maximum power dissipation of your design before applying power to the LDTC/. A jumper set lets you choose to use only the on-board potentiometer or the external voltage. Figure Source of setpoint Use On-board trimpot only Use Extermal Voltage ExtTset ExtTset Vset Vset PDset PDset JP configures the Remote Temperature Setpoint choice. There is about 00mV of hysteresis built into the default voltage. The input impedance of the R TC SET is greater than 0k and is fully buffered. If you use a different sensor or would prefer a different default voltage, contact Wavelength.. MONITOR ACTUAL TEMP AND SETPOINT Pins & 0 of Connector J are ACT T Monitor and SET T Monitor respectively. Measure the actual sensor voltage across Pin and Pin (COM). For a 0k thermistor with 00 A bias current, the resistance (in k ) is given by: R = V JPIN 0. To monitor the Setpoint Voltage used by the WTC, use Pins 0 and.. ENABLE CURRENT TO TEC Output current is supplied to the load as soon as power is applied to the controller. The Power LED indicator will light GREEN when power is applied. Online Safe Operating Area (SOA) calculators are available at: http:///support/calculator/soa/soatc.php 00 LDTC/-0000-A Rev E
S WTC OPERATION, continued PAGE LDTC/ Configuration of the LDTC for Alternate Sensors LM To use a National Semiconductor, LM temperature sensor with the LDTC, attach the LM cathode to Sensor and the LM anode to Sensor-. R BIAS, shown in Figure should be changed to k for a bias current of ma through the sensor. The voltage output of the LM is 0 mv/k. AD0 To use an Analog Devices AD0 temperature sensor with the LDTC, fi rst remove R BIAS shown in Figure. Connect the positive lead of the AD0 to a voltage supply V and the negative lead to the Sensor pin on the LDTC. The AD0 produces a current of A per degree Kelvin, giving a transfer function of 0 mv/k with a 0 k resistor connected between Sensor and ground. Figure Location of Sensor Bias Resistor D ExtTset Vset PDset CC CP J J 0 R R BIAS 0 J J R R R R R D Tset LIMA LIMB ILIM ISET ON OFF 00 LDTC/-0000-A Rev E
WLD OPERATION Recommended order of setup: WTC confi guration should be addressed fi rst, using a simulation diode load in place until the temperature control section is working properly. After the temperature control section is operating according to preferences, then the laser diode load can be confi gured. Using a simulated diode load until you are comfortable with WLD confi guration and operation is recommended in order to avoid any potential damage to an expensive laser diode. PAGE NOTE: Wavelength Electronics recommends a conservative power rating of. times normal maximum for R SENSE. Equation incorporates this recommendation. CAUTION: Operate the LDTC/ with all loads attached - if you short either the LD or TC output connections during setup, current will fl ow and possibly overheat / damage the WLD or WTC. LDTC/. SELECTING THE LASER DIODE OUTPUT CURRENT RANGE The output current range of the WLD depends on the selection of resistor R SENSE. Two 0-sized resistors combine in series to produce this total R SENSE resistance (R & R). The LDTC/ defaults the maximum range to. Amps. To change the range, and the sensitivity of the setpoint voltage, use Table or Equation, and install the appropriate R SENSE resistance. Table Laser Diode Current Sense Resistor R SENSE vs Maximum Laser Diode Current I LDMAX Maximum Output Current I LDMAX 0 ma ma 0 ma 00 ma. Amps. Amps Constant Power Current Sense Resistor, R SENSE.00 0.00.00.0.00 0. Constant Current Current Sense Resistor, R SENSE 0.00.00.00.00 0.0 0. Figure Location of R SENSE R SENSE Equation Calculating R SENSE Constant Power Mode R SENSE = Constant Current Mode R SENSE = R R 0. I LDMAX.00 I LDMAX J. HELPFUL HINTS FOR CHOOSING RSENSE Never use a carbon fi lm resistor for R SENSE. Avoid resistors with high parasitic inductance. Select a resistor with a low temperature coeffi cient (%, <00ppm/ C). Use Equation for determining the power rating of R SENSE. Equation Calculating The Power Rating for R SENSE RATING =. * (ILDMAX) * RSENSE 00 LDTC/-0000-A Rev E
WLD OPERATION, continued. CHOOSE OPERATING MODE - CONSTANT CURRENT OR CONSTANT POWER A sliding switch (S) selects operating mode. Do not move this switch while power is applied or you risk damaging your laser diode. PAGE The transfer function of the Setpoint Voltage depends on this setting for Constant Power Operation. If you choose the wrong setting, you could overdrive your laser diode. If you would prefer a different range, contact Wavelength. LDTC/ In Constant Current mode, Laser Diode I SET correlates directly to the laser diode current, regardless of laser diode power intensity. In Constant Power mode, the LDTC controls the laser diode using the photodiode to achieve a laser light intensity that is directly proportional to Laser Diode I SET. Select the mode of operation for the LDTC with the power off by setting the sliding switch S to the CC position for Constant Current mode or the CP position for Constant Power mode.. SELECT THE MONITOR PHOTODIODE CURRENT RANGEfor Constant Power Operation Select between two ranges on the LDTC/ board: 00 A or.0ma. A jumper (JP) selects the range. Move this jumper only when power is not applied to. Figure Select Photodiode Range ExtTset Vset PDset. POWER SUPPLY SELECTION The voltage supply input is common to both the WLD and the WTC. This supply furnishes the voltage to the control electronics of the devices as well as the compliance voltage for the WLD Laser Driver. The supply should be capable of providing at least.0 Amps of current in applications that use a separate VS supply in the temperature control implementation. Temperature control applications that tie and VS together require a current capacity that equals the sum of the maximum TEC or Resistive Heater current, plus the maximum laser diode current, plus approximately 00 ma for the control electronics of the WTC Temperature Controller and the WLD Laser Driver. Using the maximum potential of the WLD and WTC will not require more than.0 Amps. Performance of the laser driver is very dependent upon the performance of the power supply. The LDTC / does provide some filtering of the power supply input. For optimal performance, a power supply that can provide the appropriate level of noise and ripple for the application at hand should be utilized. ExtTset Vset PDset Setting for.0ma range Setting for 00μA range Wavelength Electronics offers a selection of switching or linear power supplies in a range of output voltage and current capacities. CAUTION: Online Safe Operating Area (SOA) calculators are available for the WLD. Calculate the maximum power dissipation of your design at http:///support/calculator/soa/soald.php before applying power to the LDTC/. 00 LDTC/-0000-A Rev E
WLD OPERATION, continued.disabling THE OUTPUT CURRENT The output current can be enabled and disabled as shown in Figure using the on-board toggle switch. Figure Disabling Output Current PAGE LDTC/ A remote voltage signal can be used to control the output status of the laser driver. Float or connect a zero Volt signal to the LD SHD (Pin on Connector J) to ENABLE output current to the laser diode. A voltage level greater than V, but less than V, will DISABLE output current to the laser diode. This input was designed for TTL inputs. The external LD SHD signal to Pin has complete control when the onboard LD Enable switch is in the ENABLE position. ON LD ENABLE OFF LD ENABLE TOGGLE SWITCH Enable LED lights GREEN when Laser Diode Current is Enabled NOTE: In order to avoid potential damage to the laser, do not insert or remove the laser diode from the WLD circuit with power applied to the unit. Always turn off the power to the unit prior to making any circuit modifications and always use proper operator grounding and anti-static procedures.. MONITOR LASER DIODE OR PHOTODIODE CURRENT Equation provides a transfer function for converting the voltage output of LD I M (Laser Diode Current Monitor - Pin of Connector J) to the amount of forward current flowing through the laser diode. Default R SENSE is 0., so default I LD = V LD I M / 0. Equation provides a transfer function for converting the voltage output of LD P M (Laser Diode Power Monitor - Pin of Connector J) to the amount of forward current flowing through the photodiode. R PD varies with the Photodiode Current range: R PD = for.0 ma range or.k for 00 A range Photodiode current can be monitored in Constant Current Mode by monitoring J Pin (PD MON) with a voltmeter. (NOTE: PIN & on J are not available on Rev. A.) The photodiode current is then given by: Equation Laser Diode Forward Current Measurement I LD V LD I M = [AMPS] *RSENSE Equation Monitor Photodiode Current Measurement in Constant Current Mode: NOTE: Available Rev. B and later. I PD = V LD P M * R PD I PD = V PDMON ( ma range) I PD = V PDMON.K (00 μa range) 00 LDTC/-0000-A Rev E
WLD OPERATION, continued. CONFIGURE THE LASER DIODE CURRENT LIMIT The default configuration of the LDTC/ uses a trimpot to adjust the Current Limit from 0 to the maximum range set in Step - WLD Operation. This trimpot is labeled ILIM (vs. LIM A or LIM B for the temperature control limit current trimpots). Fully CCW sets the limit current to the maximum. It is recommended that a simulated laser diode load is used while limit current is set. Follow Step to monitor Laser Diode Current. Adjust the trimpot until the appropriate voltage is measured.. LASER DIODE SETPOINT AND MODULATION The laser diode set point voltage determines the amount of current that is delivered to the laser. In Constant Current mode the set point is directly proportional to the laser diode current. In Constant Power mode the set point is directly proportional to the photodiode current, allowing for control of the optical power of the light emitted by the laser diode. The set point voltage can be adjusted either by using the onboard ISET trim pot, by applying an external set point voltage, or by summing an external set point voltage with the set point voltage created by adjustment of the ISET trim pot. The sum of the external set point voltage and the voltage created with the onboard ISET trim pot can be from zero to. volts. PAGE To use an external voltage source summed with the voltage supplied by the SET trim pot, place the VSET SOURCE jumper in the lower position (Pins and on JP). Connect the external voltage, or DAC output, to the R LD SET input (pin on Connector J). The final set point voltage will be the sum of the external voltage being supplied plus any Set Point voltage created with the onboard SET trim pot. To use only an external voltage source for the Set Point voltage place the VSET SOURCE jumper in the upper position (pins and on JP) and connect the external set point voltage via the R LD SET input. In this configuration, any voltage created by the onboard ISET trim pot will not be included in the final Set Point voltage which is applied to the laser driver. Equation illustrates the relationship between Set Point Voltage (V R LD SET ) and the current that will be applied to the laser diode according to the current range that has been configured for the driver using standard R SENSE resistances. Equation : I LD = R SENSE default is 0.. V R LD SET *RSENSE [AMPS] LDTC/ To use only the onboard ISET trim pot, place the VSET SOURCE jumper in the lower position (Pins and on JP), and do not connect an external voltage source to the R LD SET input. The ISET trim pot provides a Set Point adjustment of between zero to. V. Figure Laser Diode Setpoint Confi guration Equation illustrates the relationship between Set Point voltage (V R LD SET ) and the resulting photodiode current while operating in Constant Power mode for the two standard photodiode ranges that can be configured on the LDTC /. Equation : V I R LDSET PD = [AMPS] * R PD ExtTset Vset PDset ExtTset Vset PDset Use On-board trimpot Use External Voltage only R PD = for.0 ma range or.k for 00 A range I PD = V R LDSET / 000 for.0ma range default or I PD = V R LDSET / 0000 for 00 A range default 00 LDTC/-0000-A Rev E
OPERATION NOTES: Modulation caution - if operating with at V and you exceed V on R LD SET with the modulation signal for any duration, the WLD will be destroyed. WARNING: The LDTC / does not support laser diode packages that incorporate a built in sensor that is connected to or common with the laser case ground. STEPS FOR REPLACING THE WTC/ WLD: Disassemble the LDTC:. Remove cables from the unit.. Lift straight up on the cover to remove it from the base.. Remove PCB from the base plate by carefully pulling it off the corner posts.. Remove the eight screws on the bottom of the baseplate that attach the WLD and WTC to the base plate.. Use a small screwdriver to separate the WLD and WTC from the base plate. PAGE Reassemble the LDTC:. Plug the new part(s) into the PCB board before attaching it to the base to ensure that the pins do not get bent.. Make sure that the thermal sil pad or thermal paste is in good shape in order to tightly couple the WLD/WTC heat spreader to the mounting plate or heat sinking surface. Replace a questionable sil pad or spread a new thin coat of thermal paste.. Seat the holes on the PCB onto the corner posts and press PCB into seated position.. Install the eight screws in the WLD and WTC.. Install the cover and cables. LDTC/ ORDERING INFORMATION: LDTC/E LDTC/O Comes with PCB board, WLD, WTC, mounting plate, enclosure, cables Comes with PCB board, WLD, WTC, standoffs & hardware, cables For easy heasinking of Open Frame Model: WEV-00 WEV-0 WEV-0 Standard WLD or WTC thermal washer and heatsink Standard WLD or WTC thermal washer, heatsink, and V fan Standard WLD or WTC thermal washer, heatsink, and V fan 00 LDTC/-0000-A Rev E
MECHANICAL SPECIFICATIONS - LDTC/ E - with enclosure Ø0." [Ø. mm] PLACES PAGE LDTC/.0" [. mm].0" [. mm].0" [0. mm].0" [.0 mm] 0." [. mm] 0." [. mm] 0.0" [. mm].0" [. mm]." [.0 mm].0.00..00..00..0 0..0.0.0.0.00..00....00 00 LDTC/-0000-A Rev E 0..
MECHANICAL SPECIFICATIONS - LDTC/ O - Open Frame.0" [. mm] PAGE LDTC/ J J J D R.0" [.0 mm] Tset LIMA LIMB ILIM ISET D R R R R Ø0.0" [Ø. mm] S ExtTset Vset PDset CC.0" [0. mm].00" [0. mm] ON CP 0." [. mm] OFF J.0" [. mm] 0." [. mm] Ø0." [Ø.0 mm] 0.0" [. mm] 0.0" [. mm] 0.0" [. mm] 0.0.00.000.00.00 0.0 - UNC-A X /" SCREW PLS Wavelength Electronics circuit board 0.0.000 Customer mounting surface 00 Use the longer standoff when mounting unit with a fan. Use the smaller standoff for mounting directly to instrument. LDTC/-0000-A Rev E
HEATSINK FOOTPRINT." [. mm] PAGE LDTC/ Ø0." [Ø.0 mm] 0." [.0 mm] -0 tapped holes in device.0" [.0 mm].0" [0. mm] 0." [.0 mm] 0." [. mm] 0." [. mm] 0." [. mm] 0." [.0 mm] 0." [. mm].0" [. mm] 00 LDTC/-0000-A Rev E
CABLE DIAGRAMS POWER (WCB00) Connects to J PAGE 0 LDTC/ # # RED WHITE BLACK WCB-00 LDTC/ SERIES POWER CABLE PIN () (VS) (GND) WIRE COLOR RED WHITE BLACK # BLACK WHITE BLUE RED GREEN RED/BLK ORANGE WHT/BLK OUTPUT to TEC & LD (WCB0) Connects to J WCB-0 LDTC SERIES TC/LD CABLE #0 ORN/BLK GRN/BLK PIN (LDC) WIRE COLOR BLACK (PDA) (PDC) (LDA) WHITE BLUE RED (COM) GREEN (TEC) (TEC-) RED/BLACK ORANGE (SEN) (SEN-) WHITE/BLACK ORANGE/BLACK 0 (COM) GREEN/BLACK # # BLACK WHITE RED GREEN BROWN BLUE ORANGE YELLOW VIOLET GREY PINK TAN I/O (WCB0) Connects to J WCB-0 LDTC/ SERIES I/O CABLE PIN WIRE COLOR (COM) TAN (PD MON) PINK (LD SHD) GREY (COM) VIOLET (R LDSET) YELLOW (COM) ORANGE (LD PM) BLUE (LD IM) BROWN (ACT T M) GREEN 0 (SET T M) RED (R TCSET) WHITE (COM) BLACK NOTE: LDTC/ E & O Rev A DO NOT HAVE PINS & of WCB0. These were labeled as spares for Rev. A 00 LDTC/-0000-A Rev E
CERTIFICATION AND WARRANTY CERTIFICATION: Wavelength Electronics, Inc. (Wavelength) certifies that this product met its published specifications at the time of shipment. Wavelength further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology, to the extent allowed by that organization s calibration facilities, and to the calibration facilities of other International Standards Organization members. WARRANTY: This Wavelength product is warranted against defects in materials and workmanship for a period of 0 days from date of shipment. During the warranty period, Wavelength will, at its option, either repair or replace products which prove to be defective. PAGE NOTICE: The information contained in this document is subject to change without notice. Wavelength will not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material. No part of this document may be photocopied, reproduced, or translated to another language without the prior written consent of Wavelength. SAFETY: There are no user serviceable parts inside this product. Return the product to Wavelength for service and repair to ensure that safety features are maintained. LDTC/ WARRANTY SERVICE: For warranty service or repair, this product must be returned to the factory. An RMA is required for products returned to Wavelength for warranty service. The Buyer shall prepay shipping charges to Wavelength and Wavelength shall pay shipping charges to return the product to the Buyer upon determination of defective materials or workmanship. However, the Buyer shall pay all shipping charges, duties, and taxes for products returned to Wavelength from another country. LIMITATIONS OF WARRANTY: The warranty shall not apply to defects resulting from improper use or misuse of the product or operation outside published specifications. No other warranty is expressed or implied. Wavelength specifically disclaims the implied warranties of merchantability and fitness for a particular purpose. EXCLUSIVE REMEDIES: The remedies provided herein are the Buyer s sole and exclusive remedies. Wavelength shall not be liable for any direct, indirect, special, incidental, or consequential damages, whether based on contract, tort, or any other legal theory. 00 WAVELENGTH ELECTRONICS, INC. Evergreen Drive Bozeman, Montana, phone: (0) -0 Sales/Tech Support fax: (0) - e-mail: sales@teamwavelength.com web: LDTC/-0000-A Rev E LIFE SUPPORT POLICY: As a general policy, Wavelength Electronics, Inc. does not recommend the use of any of its products in life support applications where the failure or malfunction of the Wavelength product can be reasonably expected to cause failure of the life support device or to significantly affect its safety or effectiveness. Wavelength will not knowingly sell its products for use in such applications unless it receives written assurances satisfactory to Wavelength that the risks of injury or damage have been minimized, the customer assumes all such risks, and there is no product liability for Wavelength. Examples of devices considered to be life support devices are neonatal oxygen analyzers, nerve stimulators (for any use), auto transfusion devices, blood pumps, defibrillators, arrhythmia detectors and alarms, pacemakers, hemodialysis systems, peritoneal dialysis systems, ventilators of all types, and infusion pumps as well as other devices designated as critical by the FDA. The above are representative examples only and are not intended to be conclusive or exclusive of any other life support device. REVISION REV. A REV. B REV. C REV. D REV. E DATASHEET REVISION HISTORY DATE -Aug-0 0-May-0 -Nov-0 -Aug-0 -Mar-0 NOTES Initial release Contact factory if laser has LDA or LDC grounded. Updated to reflect product revision changes to improve ground bounce and setpoint drift Updated to clarify cabling and clearly indicate the differences between product Rev. A and Rev. B. Updated links to support new website Updated pin descriptions on page