iC-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 1/9 FEATURES APPLICATIONS ♦ ♦ ♦ ♦ ♦ ♦ Blue laser diodes ♦ LD modules ♦ ♦ ♦ ♦ ♦ ♦ ♦ CW operation up to 300 mA from 2.4 to 15 V supply voltage Rapid soft start after power-on typical within 70 µs Optimised for N-type laser diodes Simple output power adjustment via an external resistor (APC) Power control loop accuracy better than 1.5 % with changes in temperature, supply voltage and load current Integrated reverse polarity protection for the iC and laser diode Strong suppression of transients with very 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 LD types to be used (N/P/M configurations) Modulation via the feedback inputs is possible Wide monitor current range from 2.5 µA to 6.25 mA Pin compatible to iC-WK and iC-WKL (SO8 package) PACKAGES DFN10 4 mm x 4 mm (on request) SO8tp BLOCK DIAGRAM +2.4..+15 V 6 VCC LDA 7 CVCC CLDA ..47 nF.. ..1 uF.. TRANSIENT PROTECTION − iC−WKN 1 MDK 4 MDA 5 MD LD + VREF 0.5 V CI D LDK 2 8 NQ R RM CI 0.08..200 k Ω OVERCURRENT OVERTEMP. 1 GND ..100 nF.. FEEDBACK MON. GND AGND CM 47 pF 3 suitable laser diode configurations: N, P, M MD MD Copyright © 2004 iC-Haus LD LD LD MD http://www.ichaus.com iC-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 2/9 DESCRIPTION iC-WKN is a driver for laser diodes in continuous wave operation with laser currents of up to 300 mA, which requires only four external components. The wide power supply range of up to 15 V allows for operation of blue laser diodes. 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 other types of laser diode configuration; alternatively, it can be used as an analog modulation input (DC to a few kHz). In the event of failure, such as overcurrent in the laser path due to 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-WKN 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. iC-WKN 15 V CW LASER DIODE DRIVER Rev B1, 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 LDA 1 2 3 4 VCC 5 MDA MDA 6 VCC 7 LDA 8 LDK LDK GND CI 4 WKN code... ... 3 AGND 6 GND CI AGND MDK 5 MDK Ground Capacitance for Power Control Reference Ground for CI, RM Monitor Input 2 (MD Cathode, modulation) APC Setup, Monitor Input 1 (MD Anode) +2.4...+15 V Supply Voltage Laser Supply (LD Anode) Driver Output (LD Cathode) 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−WKN 5 4 3 ...yyww 2 1 2 3 4 GND CI AGND MDK 5 n.c. 6 MDA ... 1 PIN FUNCTIONS No. Name Function 7 8 9 10 n.c. VCC LDA LDK Ground Capacitance for Power Control Reference Ground for CI, RM Monitor Input 2 (MD Cathode, modulation) APC Setup, Monitor Input 1 (MD Anode) +2.4...+15 V Supply Voltage Laser Supply (LD Anode) Driver Output (LD Cathode) 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-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 4/9 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. ItemNo. 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(LDK) Current in LDK -10 900 mA G006 I(MDA) Current in MDA -10 10 mA G007 I(MDK) Current in MDK -10 10 mA G008 I(AGMD) Current in AGND -10 10 mA G009 I(GND) Current in GND -900 10 mA G010 Vd() ESD Susceptibility at all pins 2 kV G011 Tj Operating Junction Temperature -40 150 °C G012 Tj Storage Temperature Range -40 150 °C MIL-STD-883, Method 3015, HBM 100 pF discharged through 1.5 kΩ THERMAL DATA Operating Conditions: VCC = 2.4...15 V ItemNo. T01 T02 Symbol Parameter Conditions Fig. Unit Min. Ta Rthja Operating Ambient Temperature Range Thermal Resistance Chip/Ambient Typ. -40 soldered to PCB; no additional cooling areas therm. pad soldered to approx. 2 cm² cooling area All voltages are referenced to ground unless otherwise noted. All currents into the device pins are positive; all currents out of the device pins are negative. 30 Max. 85 °C 170 50 k/W k/W iC-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 5/9 ELECTRICAL CHARACTERISTIC Operating Conditions: VCC = 2.4...15 V, RM = 80 Ω...200 kΩ, Tj = -40...125 °C unless otherwise noted ItemNo. Symbol Parameter Conditions Tj °C Unit Fig. Min. Typ. Max. Total Device 001 VCC Permissible Supply Voltage 002 I(LDK)m Permissible Laser Drive Current 003 Idc(VCC) Supply Current without load path closed control loop, I(MDK) = 0, I(LDK) = 290 mA 004 Ioff(VCC) Supply Current on Reset 005 006 Ir(VCC) Reverse Supply Current RM = 50 kΩ, VCC = -6 V ton() Turn-on Delay VCC: 0 → 5 V to 95 % I(LDK), I(LDK) = I(LDK)m; CI = 47 nF CI = 100 nF power control range 2.4 15 V 10 300 mA 10 20 mA 2.4 5 mA -6 -3 mA 70 150 µs µs 007 Vc()hi Clamp Voltage hi at VCC, LDA I()= 10 mA, other pins open 16 24 V 008 Vc()hi Clamp Voltage hi at LDK V() < VCC + 1 V; I() = 10 mA, other pins open 16 24 V 009 Vc()hi Clamp Voltage hi at MDK vs. LDA I() = 10 mA, other pins open 8 11 V 010 Vc()hi Clamp Voltage hi at MDA, CI I() = 10 mA, other pins open 1.1 4 V 011 Vc()lo Clamp Voltage lo at VCC, LDA, MDK, MDA, CI I() = -10 mA, other pins open -9 V Reference and Monitor Inputs MDA, MDK, AGND 101 V(MDA) Reference Voltage at MDA closed control loop, V(LDK) > Vs(LDK) 102 dV(MDA) Reference Voltage Temperature Drift at MDA see 101 103 Ierr(MDA) Input Current in MDA closed control loop, I(MDK) = 0, I(LDK) = 10...290 mA 104 dI(MDA) Input Current Temperature Drift in see 103 MDA 105 APCerr Control Error RM = 10 kΩ, Tj = 0...80 °C RM = 10 kΩ, Tj = -40...125 °C 106 dI(RM) Supply Voltage Suppression V(VCC): 2.4 → 15 V, I(LDK) = 290 mA -1.5 107 Rgnd() Resistor AGND-GND 108 Vf(MDK) Voltage at MDK Vf() = V(LDA) - V(MDK), I(MDK) = 1 µA...1 mA 0.46 109 CR() Current Ratio I(MDA) / I(MDK) I(MDK) = 1 µA...1 mA I(MDK) = 1..6 mA 0.98 0.95 1.02 1.05 110 TC() Current Ratio Temperature Coefficient I(MDA) / I(MDK) I(MDK) = 1 µA...1 mA I(MDK) = 1...6 mA -0.005 -0.025 0.005 0.025 %/°C %/°C 350 700 mV mV Laser Driver LDA, LDK 201 Vs(LDK) Saturation Voltage at LDK 480 520 mV 120 µV/°C -100 100 nA -1 1 nA/°C 0.3 1 % % 1.5 % 3 Ω 2 V I(LDK) = 40 mA I(LDK) = 290 mA 500 202 dI(LD) Load Balancing Error I(LD) = 20 mA, I(LDK): 20 mA → 290 mA -1.5 1.5 % 203 It(LDK) Overcurrent Threshold in LDK V(LDK) = 2...5.5 V 300 700 mA 204 It(LDK)m Maximum Overcurrent Threshold in LDK 1.2 A 205 toff() Overcurrent Reset Delay lack of feedback: I(MD) = 0 to I(LDK) = It(LDK); CI = 47 nF CI = 100 nF 85 170 µs µs 1.3 V 1.3 Ω 2 V 206 Vf() Flyback Diode Forward Voltage LDK-LDA I(LDK) < 290 mA 207 Rvcc() Transient Protection Resistor VCC to LDA 208 Vt(MDA) Shutdown Threshold at MDA t > 1 µs 0.7 iC-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 6/9 ELECTRICAL CHARACTERISTIC Operating Conditions: VCC = 2.4...15 V, RM = 80 Ω...200 kΩ, Tj = -40...125 °C unless otherwise noted ItemNo. Symbol Parameter Control Release Flip-Flop 401 VCCen Set Threshold for Enable Flip-Flop 402 Toff Overtemperature Shutdown Conditions Tj °C -40 27 125 Unit Fig. Min. Typ. Max. 0.6 1.2 1.0 0.6 1.9 1.9 1.7 1.2 V V V V 140 165 °C iC-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 7/9 SAFETY PRECAUTIONS 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 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 LDA. 5V 4V 3V tor determining the lowest possible supply voltage. If the voltage drops below this value, the output driver is forcibly saturated and the laser current decreases. iC-WKN simultaneously discharges the control capacitor CI so that no excessive laser diode currents occur when the supply voltage rises again. 2V 1V 0 V(VCC) 5V 4V 5V 4V 3V 2V Phase I Phase II 3V Phase III 2V 1V 1V 0 V(LDA) 0 V(VCC) 400 mV 5V 300 mV 4V 200 mV 3V 2V 100 mV 1V V(MDA) 0 V(LDA) 1V 400 mV 300 mV 500 mV 200 mV 0 V(CI) 100 mV V(MDA) 60 m 40 m 1V 20 m 0 I(LDK) Phase IV 500 mV 0 10 us 20 us Time 30 us 40 us 50 us Phase V 0 V(CI) 60 m Figure 1: Turn-on behaviour 40 m 20 m 0 I(LDK) A quick soft-start follows during phase I; the control capacitor CI is charged at an accelerated rate until the voltage at pin MDA reaches 1/3 of its nominal value. With V (MDA) > 1/3V (MDA)nom phase II starts, the controlled start-up. The transition to CW operation (phase III) 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. Turn-off behaviour iC-WKN works without a fixed undervoltage lockout, thus the laser diode forward voltage is the prime fac- 100 us 110 us 120 us Time 130 us 140 us 150 us 160 us Figure 2: Turn-off behaviour 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 250 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-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 8/9 APPLICATION NOTES 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 a fixed resistor (max. output power) and a trimmer (calibration). Further application notes on the iC-WK family (iC-WK, iC-WKL, iC-WKN) and the data sheet of the demo board are available as separate documents. 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-WKN 15 V CW LASER DIODE DRIVER Rev B1, Page 9/9 ORDERING INFORMATION Type Package Order Designation iC-WKN SO8tp DFN10 4 mm x 4 mm iC-WKN SO8 iC-WKN DFN10 Demo Board WKN4D DEMO 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]