WKPDFN10

WKPDFN10 ICHAUS | Alldatasheet

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Technical content

15 V CW P-TYPE LASER DIODE DRIVER

Rev A6, Page 1/10

FEATURES

♦ Optimised for P-type laser diodes (case grounded) ♦ CW operation up to 350 mA from 3 to 15 V supply voltage ♦ Rapid soft start after power-on ♦ Simple power adjustment via an external resistor ♦ Control loop accuracy better than 2% with changes in temperature, supply voltage and load current ♦ 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 chip temperature and overcurrent (i.e. if the laser diode is damaged or the feedback current path fails) ♦ Second feedback input MDA also permits the operation of N-type laser diodes ♦ Modulation via the feedback inputs possible ♦ Wide monitor current range from 2.5 µA to 6.25 mA

APPLICATIONS

♦ Laser diode modules ♦ Laser diode pointers ♦ Pilot lasers ♦ Laser levels ♦ Barcode readers ♦ Distance measuring sensors PACKAGES SO8-TP (thermal pad) DFN10 4 mm x 4 mm BLOCK DIAGRAM Pin numbers given for SO8 package only Copyright © 2010 iC-Haus http://www.ichaus.com

Rev A6, Page 2/10

DESCRIPTION

iC-WKP is a driver for laser diodes in continuous wave (CW) operation with laser currents of up to 350 mA from a wide power supply range of up to 15 V which requires only four external components. The driver is optimised for P-type laser diodes and allows the connection of the laser diode case to ground. The iC includes integrated circuitry protecting against destruction by ESD, excessive temperature and over- current 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 ex- ternal resistor at MDK. The monitor current acts as a reference and is regulated independent of the in- fluence 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 MDA, allows the driver to be used for N-type laser diode configuration; alter- natively, 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 dis- turbance. iC-WKP offers additional protection by means of spike detection at pin MDK. Should spikes or oscilla- tion occur at pin MDK the power lockout is activated after a certain time-out.

Rev A6, Page 3/10 PACKAGES SO8tp, DFN10 4 mm x 4 mm to JEDEC standard PIN CONFIGURATION SO8tp CI MDK AGND MDA VCC WKPGND VCCA LDA code... ... PIN FUNCTIONS No. Name Function

1 CI Capacitor for Power Control

2 GND Ground

3 AGND Reference Ground for CI

4 MDK APC Setup,

Monitor Input 1 (MD Cathode)

5 MDA Monitor Input 2

(MD Anode, modulation)

6 VCCA Driver Supply

7 VCC +3 to +15 V Supply Voltage

8 LDA Driver Output (LD Anode)

PIN CONFIGURATION DFN10 4 mm x 4 mm 4 7 ... ...yyww iC−WKP PIN FUNCTIONS No. Name Function Monitor Input 1 (MD Cathode) 5 n.c.

6 MDA Monitor Input 2

(MD Anode, modulation)

7 VCCA Driver Supply

8 VCC +3 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 as this may affect the precision of the regulator and interfere with the soft start!

Rev A6, Page 4/10 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. Item Symbol Parameter Conditions Unit No. 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 HBM, 100 pF discharged through 1.5 kΩ 2 kV G011 Tj Operating Junction Temperature -40 150 °C G012 Ts Storage Temperature Range -40 150 °C THERMAL DATA Operating Conditions: VCC = 3...15 V Item Symbol Parameter Conditions Unit No. Min. Typ. Max. T01 Ta Operating Ambient Temperature Range -40 85 °C T02 Rthja Thermal Resistance Chip/Ambient SMD assembly, no additional cooling areas 170 K/W T03 Rthja Thermal Resistance Chip/Ambient Therm. pad soldered to approx. 2 cm² cooling area 30 50 K/W All voltages are referenced to ground unless otherwise stated. All currents flowing into the device pins are positive; all currents flowing out of the device pins are negative.

Rev A6, Page 5/10

ELECTRICAL CHARACTERISTICS

Item Symbol Parameter Conditions Unit No. Min. Typ. Max. Total Device

001 VCC Permissible Supply Voltage 3 15 V

002 I(LDA)m Permissible Laser Drive Current

(closed control loop) Control range -350 -10 mA

003 Idc(VCC) Supply Current without load path Closed control loop, I(MDK) = 0,

I(LDA) = -350 mA 5 10 mA 004 Ioff(VCC) Supply Current after Reset 2.4 5 mA

005 Ir(VCC) Reverse Supply Current RM = 50 kΩ, VCC = -6 V -15 -3 mA

006 ton() Turn-on Delay VCC: 0 →5 V to 95% I(LDA), I(LDA) = I(LDA)m, CI = 3.3 µF 600 µs

007 Vc()hi Clamp Voltage hi at MDA I() = 10 mA, other pins open 1 4 V

008 Vc()lo Clamp Voltage lo at

VCC, LDA, MDA, CI, VCCA I() = -10 mA, other pins open -9 V

009 Vc()hi Clamp Voltage hi at MDK refer-

I() = 10 mA, other pins open 8 11 14 V

010 Vc()lo Clamp Voltage lo at MDK refer-

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 Reference and Monitor Inputs MDA, MDK, AGND

101 Vref(MDK) Reference Voltage at MDK Vref(MDK) = VCCA −V(MDK),

closed control loop, VCC −V(LDA) > Vs(LDA) 1.18 1.24 1.30 V 102 dV(MDK) Reference Voltage Temperature Drift at MDA See 101 120 µV/°C

103 Ierr(MDK) Input Current in MDK Closed control loop, I(MDA) = 0 -300 300 nA

104 dI(MDK) Input Current Temperature Drift in MDK See 103 -1 1 nA/°C

105 APCerr Control Error RM = 10 kΩ;

106 dI(MD) Supply Voltage Suppression V(VCC): 3 →15 V, I(LDA) = -350 mA -2 2 %

107 Rgnd() Resistor AGND-GND 3 Ω

109 TC() Current Ratio Temperature

Coefficient I(MDA)/I(MDK) -0.025 0.025 %/°C Laser Driver LDA

201 Vs(LDA) Saturation Voltage at LDA

Vs(LDA) = V(VCC) −V(LDA); I(LDA)= -40 mA 0.9 V I(LDA)= -350 mA 1.3 V 202 dI(MDK) Load Balancing Error I(LDA): -20 →-350 mA -2.5 2 %

203 It(LDA) Overcurrent Threshold in LDA -700 -360 mA

204 toff() Overcurrent Reset Delay Lack of feedback: I(MD) = 0 to I(LDA) > -10 mA, VCC = 5 V, CI = 3.3 µF 600 µs

205 Vf() Flyback Diode Forward Voltage

V(GND)-V(LDA) I(LDA) > -350 mA 1.5 V

206 Rvcc() Transient Protection Resistor VCC to VCCA 3 Ω

207 Vt(MDK) Shutdown Threshold at MDK Vt(MDK) = V(VCCA) −V(MDK), t > 1 µs 1.35 2.1 V Control Release Flip-Flop

401 VCCen Set Threshold for Enable Flip-

0.6 1.9 V

402 Toff Overtemperature Shutdown 140 165 °C

Rev A6, Page 6/10 SAFETY INSTRUCTIONS Laser light can damage the human eye and the eyes of animals! Do not look at any laser light di- rectly 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 = Vref(MDK) / I(MD), where Vref(MDK) = Item No. 101 and I(MD) = the 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 (calibra- tion). 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. 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 undershoot at MDK is at a minimum. 0 50us 100us 150us 200us 250usTime 100mA 200mA V(CI) I(LD) V(LDA) 500mV 1.0V 1.5V V(MDK) VCC − 1.5V VCC − 1V VCC − 0.5V VCC Figure 1: Turn-on behaviour Turn-off behaviour iC-WKP works without a fixed undervoltage lockout, thus the laser diode forward voltage is the prime fac- tor determining the lowest possible supply voltage. If the voltage drops below this value, the output stage is forcibly saturated and the laser current decreases. iC-WKP simultaneously discharges control capacitor CI so that no excessive laser diode currents occur when the supply voltage again rises. I(LD) 1ms 1,01ms 1,02msTime 100mA 200mA V(CI) V(LDA) 500mV 1.0V 1.5V V(MDK) VCC − 1V VCC − 0.5V VCC 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 path is interrupted. If the monitor diode or 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 MDA, low voltage occurring at pin MDK may also cause a shut- down.

Rev A6, Page 7/10 APPLICATION NOTES Laser diode types Two laser diode types can be operated by iC-WKP . Figure 3: Operation of a P-type laser diode As iC-WKP has been optimised for use with P-type laser diodes, it is with this type of diode that the best functionality is achieved. This type of setup also en- ables the laser diode package to be connected to GND. Figure 4: Operation of an N-type laser diode The operation ofN-type laser diodes it is also possible. Here, however, the current mirror at MDA introduces a certain error to the automatic power control (c.f. Elec- trical Characteristics Nos. 108–110); iC-WKN, which has been optimised for use with these diodes, may be a better choice. iC-WKP does not allow for the operation of M-Type laser diodes. For these laser diode types iC-WKM would be the best choice. Layout To prevent instability of the regulator an additional ca- pacitor (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 with RM may be required for stability. RL may be introduced to improve stability even further and additionally reduce the power dissi- pation of iC-WKP . Pin AGND acts solely as a ground reference for the power regulator (CI and RM) and should not be short- circuited with GND externally. This could have a neg- ative effect on the control behaviour and monitor func- tions. Cooling Laser diodes should be sufficiently cooled, particularly with the power-regulated operation of setups which use iC-WKP , 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 cur- rent. This in turn brings about a rise in power dissipa- tion in the laser diode and thus also in temperature. In this instance the laser diode could be damaged (result- ing in spottiness of the laser beam and an increase in operating current) or even destroyed before the over- current shutdown threshold in iC-WKP is reached.

Rev A6, Page 8/10 EVALUATION BOARD iC-WKP comes with an evaluation board for test purpose. Figures 5 and 6 show both the schematic and the component side of the evaluation board. R CI 500k PMC L CVCC1 100nF 100nF CLDA opt. D1 P LDA LDC MDC GND 2.2nF CM CI2 3AGND CI 1 GND2 LDA 8 MDA 5 MDK 4 SUB EPAD

7 VCC VCCA 6

opt. CVCC2 iC-WKP D2 N LDA LDC MDA VCC RL RM 100pF CI1 VCCA LDA MDA MDKMDK LDA MDA RM CI1 100pF VCCA VCC RL ND2 CVCC2 opt. 1.24V iC-WKP AGND CM 2.2nF opt. CI2 PD1 GND 100nF CVCC1 CLDA 100nF PM 500k CI Figure 5: Schematic of the evaluation board

Rev A6, Page 9/10 Figure 6: Evaluation board (component side) iC-Haus expressly reserves the right to change its products and/or specifications. An info letter gives details as to any amendments and additions made to the relevant current specifications on our internet website www.ichaus.de/infoletter; this letter is generated automatically and shall be sent to registered users by email. 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 and does not assume liability for any errors or omissions in these 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. As a general rule our developments, IPs, principle circuitry and range of Integrated Circuits are suitable and specifically designed for appropriate use in technical applications, such as in devices, systems and any kind of technical equipment, in so far as they do not infringe existing patent rights. In principle the range of use is limitless in a technical sense and refers to the products listed in the inventory of goods compiled for the 2008 and following export trade statistics issued annually by the Bureau of Statistics in Wiesbaden, for example, or to any product in the product catalogue published for the 2007 and following exhibitions in Hanover (Hannover-Messe). We understand suitable application of our published designs to be state-of-the-art technology which can no longer be classed as inventive under the stipulations of patent law. Our explicit application notes are to be treated only as mere examples of the many possible and extremely advantageous uses our products can be put to.

Rev A6, Page 10/10

ORDERING INFORMATION

Type Package Order Designation iC-WKP SO8-TP iC-WKP SO8-TP DFN10 4 mm x 4 mm iC-WKP DFN10 Evaluation Board iC-WKP EVAL WKP1D For technical support, information about prices and terms of delivery please contact: iC-Haus GmbH Tel.: +49 (61 35) 92 92-0 Am Kuemmerling 18 Fax: +49 (61 35) 92 92-192 D-55294 Bodenheim Web: http://www.ichaus.com GERMANY E-Mail: sales@ichaus.com Appointed local distributors: http://www.ichaus.com/sales_partners