iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 1/9 FEATURES APPLICATIONS ♦ Optimised for M-type laser diodes (single supply, case grounded) ♦ CW operation up to 350 mA from a single supply of 3.6 to 15 V ♦ Rapid soft start after power-on ♦ Simple power adjustment via an external resistor ♦ Integrated reverse polarity protection for the iC and laser diode ♦ Strong suppression of transients with small external capacitors; integrated flyback path ♦ Permanent shutdown with excessive temperature and overcurrent (i.e. if the laser diode is damaged or the feedback current path fails) ♦ Two feedback inputs permit all current laser diode types to be used (M/P/N configurations) ♦ Modulation via the feedback inputs possible ♦ Wide monitor current range from 2.5 µA to 6.25 mA ♦ ♦ ♦ ♦ ♦ Blue laser diodes Laser diode modules Laser diode pointers Laser levels Bar-code readers PACKAGES SO8tp thermal pad DFN10 4 mm x 4 mm BLOCK DIAGRAM Pin numbers given for SO8 package only. Copyright © 2006 iC-Haus http://www.ichaus.com iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 2/9 DESCRIPTION iC-WKM is a driver for laser diodes in continuous wave operation with laser currents of up to 350 mA, which requires only four external components. The wide power supply range of up to 15 V allows for operation of blue laser diodes, e.g. by Nichia or Sanyo. The driver is optimised for M-type laser diodes and allows the operation from a single supply and the connection of the laser diode case (common cathode) with ground. The iC includes integrated circuitry protecting against destruction by ESD, excessive temperature and overcurrent plus a soft start of the regulator to protect the laser diode when the power supply is switched on. The iC also filters the laser diode power supply for transients. The regulator is adapted to the laser diode by an external resistor at MDA. The monitor current acts as a reference and is regulated independent of the influence of temperature and supply voltage (range: 2.5 µA to 6.25 mA). The capacitor at CI determines the control time constants and start-up time. A second monitor input, pin MDK, allows the driver to be used for P-type laser diode configuration; alternatively, it can be used as an analogue modulation input (DC to a few kHz). In the event of failure, such as overcurrent in the laser path with a lack of feedback, for example, a quick power lockout is activated. The shutdown persists until power is reapplied, permitting a restart. The strain on power packs and batteries is relieved and the laser class is retained even in the event of a disturbance. iC-WKM offers additional protection by means of spike detection at pin MDA. Should spikes or oscillation occur at pin MDA the power lockout is activated after a certain time-out. ar y n i im prel iC-WKM M-TYPE CW LASER DIODE DRIVER Rev C1, Page 3/9 PACKAGES SO8tp, DFN10 4 mm x 4 mm to JEDEC standard PIN CONFIGURATION SO8tp (top view) PIN FUNCTIONS No. Name Function 1 8 2 7 CI LDA GND VCC AGND 4 WKM code... ... 3 6 VCCA 5 MDK MDA 1 2 3 4 CI GND AGND MDK Capacitor for Power Control Ground Reference Ground for CI, RM Monitor Input 2 (MD Cathode, modulation) 5 MDA APC Setup, Monitor Input 1 (MD Anode) 6 VCCA Driver Supply 7 VCC +3.6 to 15 V Supply Voltage 8 LDA Driver Output (LD Anode) The Thermal Pad is to be connected to a Ground Plane on the PCB. Do not short-circuit pins AGND and GND, for this may deteriorate the precision of the regulator and interfere with the soft-start! 6 7 8 9 10 PIN CONFIGURATION DFN10 4 mm x 4 mm (top view) iC−WKM 5 4 3 ...yyww 2 1 2 3 4 CI GND AGND MDK Capacitor for Power Control Ground Reference Ground for CI, RM Monitor Input 2 (MD Cathode, modulation) 5 n.c. 6 MDA ... 1 PIN FUNCTIONS No. Name Function APC Setup, Monitor Input 1 (MD Anode) 7 VCCA Driver Supply 8 VCC +3.6 to 15 V Supply Voltage 9 LDA Driver Output (LD Anode) 10 n.c. The Thermal Pad is to be connected to a Ground Plane on the PCB. Do not short-circuit pins AGND and GND, for this may deteriorate the precision of the regulator and interfere with the soft-start! iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 4/9 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. Item No. Symbol Parameter Conditions Fig. Unit Min. Max. G001 VCC Voltage at VCC -6 16 V G002 I(VCC) Current in VCC -10 900 mA G003 I(CI) Current in CI -10 10 mA G004 I(LDA) Current in LDA -900 10 mA G005 I(VCCA) Current in VCCA -10 10 mA G006 I(MDA) Current in MDA -10 10 mA G007 I(MDK) Current in MDK -10 10 mA G008 I(AGND) Current in AGND -10 10 mA G009 I(GND) Current in GND -10 900 mA G010 Vd() ESD Susceptibility at all pins 2 kV G011 Tj Operating Junction Temperature -40 150 °C G012 Ts Storage Temperature Range -40 150 °C MIL-STD-833, method 3015, HBM 100 pF discharged via 1.5 kΩ THERMAL DATA Operating Conditions: VCC = 3.6...15 V Item No. Symbol Parameter Conditions Fig. Unit Min. T01 Ta Operating Ambient Temperature Range T02 Rthja Thermal Resistance Chip/Ambient SMD assembly, no additional cooling areas T03 Rthja Thermal Resistance Chip/Ambient therm. pad soldered to approx. 2 cm² cooling area Typ. -40 All voltages are referenced to ground unless otherwise stated. All currents into the device pins are positive; all currents out of the device pins are negative. 30 Max. 85 °C 170 K/W 50 K/W iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 5/9 ELECTRICAL CHARACTERISTICS Operating Conditions: VCC = 3.6...15 V, RM = 40 Ω...100 kΩ, Tj = -40...125 °C unless otherwise noted Item No. Symbol Parameter Conditions Tj °C Fig. Unit Min. Typ. Max. Total Device 001 VCC Permissible Supply Voltage 002 I(LDA)m Permissible Laser Drive Current 003 Idc(VCC) Supply Current without load path closed control loop, I(MDK) = 0, I(LDA) = 350 mA 004 Ioff(VCC) Supply Current after Reset 005 Ir(VCC) Reverse Supply Current RM = 50 kΩ, VCC = -6 V 006 ton() Turn-on Delay VCC: 0 → 5 V to 95%I(LDA); I(LDA) = I(LDA)m, CI = 3.3 µF 007 Vc()hi Clamp Voltage hi at MDA I() = 10 mA, other pins open 1.1 008 Vc()lo Clamp Voltage lo at VCC, LDA, MDA, CI, VCCA I() = -10 mA, other pins open -9 009 Vc()hi Clamp Voltage hi at MDK referenced to VCCA I() = 10 mA, other pins open 6 11 V 010 Vc()lo Clamp Voltage lo at MDK referenced to VCCA I() = -10 mA, other pins open -11 -1 V 011 Vc()hi Clamp Voltage hi at VCC, LDA, CI, VCCA I() = 10 mA, other pins open 16 24 V 230 270 mV 120 µV/°C control range 3.6 15 V -350 -10 mA 5 10 mA 2.4 5 mA -10 -3 mA 600 µs 4 V V Reference and Monitor Inputs MDA, MDK, AGND 101 V(MDA) Reference Voltage at MDA closed control loop, V(LDA) < Vs(LDA) 102 dV(MDA) Reference Voltage Temperature Drift at MDA see 101 103 Ierr(MDA) Input Current in MDA closed control loop, I(MDK) = 0 104 dI(MDA) Input Current Temperature Drift in see 103 MDA 105 APCerr Control Error -100 100 nA -1 1 nA/°C 0.5 2 % % -4 4 % 3 Ω RM = 10 kΩ; Tj = 0...80 °C Tj= -40...125 °C V(VCC): 3.6 V → 15 V, I(LDA) = -350 mA 250 106 dI(MD) Supply Voltage Suppression 107 108 Rgnd() Resistor AGND-GND CR() Current Ratio I(MDA)/I(MDK) I(MDK) = 1...500 µA I(MDK) = 0.5...3 mA I(MDK) = 3...6 mA 0.97 0.95 0.92 1.03 1.05 1.06 109 TC() Current Ratio Temperature Coefficient I(MDA)/I(MDK) I(MDK) = 1 µA...1 mA -0.005 0.005 %/°C 110 TC() Current Ratio Temperature Coefficient I(MDA)/I(MDK) I(MDK) = 1...6 mA -0.025 0.025 %/°C 111 Vf(MDK) Voltage at MDK Vf() = V(VCCA) − V(MDK), I(MDK) = 1 µA...6 mA 0.4 2 V 1.0 1.5 V V Laser Driver LDA 201 Vs(LDA) Saturation Vs(LDA) = V(VCC) − V(LDA); Voltage at LDA referenced to VCC I(LDA)= -40 mA I(LDA)= -350 mA 202 dI(MDA) Load Balancing Error 203 It(LDA) Overcurrent Threshold in LDA 204 toff() Overcurrent Reset Delay 205 Vf() 206 207 I(LDA): -20 → -350 mA -5 4 % -700 -360 mA lack of feedback: I(MD) = 0 to I(LDA) > -10 mA, VCC = 5 V, CI = 1 µF 600 µs Flyback Diode Forward Voltage V(GND)-V(LDA) I(LDA) > -350 mA 1.5 V Rvcc() Transient Protection Resistor VCC to VCCA 3 Ω Vt(MDA) Shutdown Threshold at MDA t > 1 µs 1.8 V 0.7 iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 6/9 ELECTRICAL CHARACTERISTICS Operating Conditions: VCC = 3.6...15 V, RM = 40 Ω...100 kΩ, Tj = -40...125 °C unless otherwise noted Item No. Symbol Parameter Conditions Tj °C Fig. Unit Min. Typ. Max. Control Release Flip-Flop 301 VCCen Set Threshold for Enable Flip-Flop 0.6 1.9 V 302 Toff Overtemperature Shutdown 140 165 °C ar y n i im prel iC-WKM M-TYPE CW LASER DIODE DRIVER Rev C1, Page 7/9 SAFETY INSTRUCTIONS Laser light can damage the human eye and the eyes of animals! Do not look at any laser light directly or through any optical lens. When handling a laser diode, do not look directly at the light generated by it. Wear appropriate safety glasses to prevent light from entering the eye even by reflection. FUNCTION DESCRIPTION Setting the output power The output power is simply set by RM = V(MDA) / I(MD); with V(MDA) = Item-No. 101 and I(MD) = monitor current of the laser diode at the desired operating point. RM should be combined from fixed resistor (max. output power) and a trimmer (calibration). If the voltage drops below this value, the output stage is forcibly saturated and the laser current decreases. iC-WKM simultaneously discharges the control capacitor CI so that no excessive laser diode currents occur when the supply voltage rises again. V(MDA) Turn-on behaviour After switching the supply voltage on, the output stage remains disabled until the internal enabling flip-flop is set by a sufficiently high voltage at VCC. 200mV 100mV 0 −100mV V(LDA) 1,5V A quick soft start follows; the transition to controlled CW operation is gradual and primarily determined by the values of CI and RM. CI is properly dimensioned when the voltage overshoot at MDA is at a minimum. 1,0V 500mV 0 V(CI) 2V 1V V(MDA) 200mV 0 100mV I(LD) 200mA 0 100mA −100mV 0 V(LDA) 1000us 1,5V Time 1,01ms 1,02ms 1,0V Figure 2: Turn-off behaviour 500mV 0 V(CI) 2V 1V 0 I(LD) 200mA 100mA 0 0 50us 100us Time 150us 200us 250us Figure 1: Turn-on behaviour Turn-off behaviour iC-WKM works without a fixed undervoltage lockout, thus the laser diode forward voltage is the prime factor determining the lowest possible supply voltage. Disruptions in operation The power control is shut down with excessive driver temperature or when the laser current reaches the overcurrent shutdown threshold, for example when the feedback is interrupted. If the monitor diode or the bias resistor RM fail, the device is shut down in less than 600 µs, provided that the supply voltage applied is high enough. When modulating the laser current via pin MDK, excessive voltage occurring at pin MDA also may cause a shutdown. iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 8/9 APPLICATION NOTES Laser diode types In principle, all three laser diode types can be operated by iC-WKM. As iC-WKM has been optimised for use with M-type laser diodes, it is with this type of diode that the best functionality is achieved. This type of setup also enables the laser diode package to be connected to GND. With P-type laser diodes it is also possible to connect the laser diode package to GND. Here, however, the current mirror at MDK introduces a certain error to the automatic power control (c.f. Electrical Characteristics Nos. 108-110). Even N-type laser diodes can be operated by iC-WKM; iC-WKN, however, which has been optimised for use with these diodes, may be a better choice. Figure 3: Operation of an M-type laser diode Layout To prevent instability of the regulator an additional capacitor (ca. 100 pF) must be positioned directly at the iC’s pin CI. Depending on the laser diode, capacitor CM with typ. 2 nF in parallel to RM may be required for stability. Pin AGND acts solely as a ground reference for the power regulator (CI and RM) and should not be shortcircuited with GND externally. This could have a negative effect on the control behavior and monitor functions. Figure 4: Operation of a P-type laser diode Figure 5: Operation of an N-type laser diode Cooling Laser diodes should be sufficiently cooled, particularly with the power-regulated operation of setups which use iC-WKM, for example. The power dissipation in the laser diode otherwise causes the diode to heat up and the level of efficiency to drop which the power control unit then compensates for by increasing the laser current. This in turn brings about a rise in power dissipation in the laser diode and thus also in temperature. In this instance the laser diode could be damaged (resulting in spottiness and an increase in operating current) or even destroyed before the overcurrent shutdown threshold in iC-WKM is reached. This applies in particular to blue laser diodes whose power dissipation is considerably higher than that of red laser diodes, for example, due to the higher forward voltage. This specification is for a newly developed product. iC-Haus therefore reserves the right to change or update, without notice, any information contained herein, design and specification; and to discontinue or limit production or distribution of any product versions. Please contact iC-Haus to ascertain the current data. Copying – even as an excerpt – is only permitted with iC-Haus approval in writing and precise reference to source. iC-Haus does not warrant the accuracy, completeness or timeliness of the specification on this site and does not assume liability for any errors or omissions in the materials. The data specified is intended solely for the purpose of product description. No representations or warranties, either express or implied, of merchantability, fitness for a particular purpose or of any other nature are made hereunder with respect to information/specification or the products to which information refers and no guarantee with respect to compliance to the intended use is given. In particular, this also applies to the stated possible applications or areas of applications of the product. iC-Haus conveys no patent, copyright, mask work right or other trade mark right to this product. iC-Haus assumes no liability for any patent and/or other trade mark rights of a third party resulting from processing or handling of the product and/or any other use of the product. iC-WKM M-TYPE CW LASER DIODE DRIVER ar y n i im prel Rev C1, Page 9/9 ORDERING INFORMATION Type Package Order Designation iC-WKM SO8tp DFN10 4 mm x 4 mm iC-WKM SO8 iC-WKM DFN10 Evaluation Board iC-WKM EVAL WKM1D For information about prices, terms of delivery, other packaging options etc. please contact: iC-Haus GmbH Am Kuemmerling 18 D-55294 Bodenheim GERMANY Tel.: +49 (61 35) 92 92-0 Fax: +49 (61 35) 92 92-192 Web: http://www.ichaus.com E-Mail: [email protected]