iC-WK, iC-WKL 2.4 V CW LASER DIODE DRIVER Rev D1, Page 1/8 FEATURES APPLICATIONS CW operation up to 90 mA from 2.4 to 6 V supply voltage Battery-powered LD modules LD Pointers Rapid soft start after power-on typical within 70 s Simple power adjustment via the external resistor Laser levels Control loop accuracy better than 1% with changes in Bar-code readers 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 yback path Permanent shutdown with excessive temperature and overcurrent (i.e. if the laser diode is damaged or the feedback current path fails) PACKAGES Two feedback inputs permit all current LD types to be used (N/P/M congurations) Modulation via the feedback inputs is possible Wide monitor current range from 10 A to 2.5 mA iC-WK with additional spike detection at monitor input MDA SO8 MSOP8 BLOCK DIAGRAM 6 7 +2.4..+6 V VCC LDA CVCC CLDA ..1 uF..47 nF.. TRANSIENT 4 PROTECTION MDK MD LD 5 MDA + iCWKL VREF 0.5 V 2 CI 1 D 8 LDK NQ R CM RM CI 200..50 k W 47 pF ..100 nF.. iCWK OVERCURRENT/ OVERTEMP. FEEDBACK MON. 1 3 GND AGND GND suitable laser diode configurations: N, P, M MD LD LD MD MD LD Copyright 2006 iC-Haus WK iCWK code... Code ... iC-WK, iC-WKL 2.4 V CW LASER DIODE DRIVER Rev D1, Page 2/8 DESCRIPTION The iC-WK/L device is a driver for laser diodes in con- CI determines the control time constants and start-up tinuous wave operation which requires only four ex- time. ternal components. The wide power supply range of 2.4 to 6 V and the integrated reverse battery protec- A second monitor input, pin MDK, allows the driver to tion allow for battery operation with a minimum of two be used for other types of laser diode conguration cells. A reversed battery connection destroys neither alternatively, it can be used as an analogue modula- the iC nor the laser diode. tion input (DC to a few kHz). The iC includes integrated circuitry protecting against In the event of failure, such as overcurrent in the laser destruction by ESD, excessive temperature and over- path with a lack of feedback, for example, a quick current and a soft start which regulates the power power lockout is activated. The shutdown continues and protects the laser diode when the power supply until power is reapplied, permitting a restart. The is switched on. The iC also lters the laser diode strain on power packs and batteries is relieved and power supply for transients. the laser class is retained even in the event of a dis- turbance. The power supply is regulated and adapted to the laser diode used by an external resistor at MDA. The iC-WK offers additional protection by means of spike monitor current acts as a reference and is regulated detection at pin MDA. Should spikes or oscillation independent of the inuence of temperature and sup- occur at pin MDA the power lockout is activated. ply voltage (range: 10 A to 2.5 mA). The capacitor at PACKAGES SO8, MSOP8 to JEDEC PIN CONFIGURATION SO8 PIN FUNCTIONS (top view) No. Name Function 1 GND Ground 1 8 2 CI Capacitance for Power Control LDK GND 3 AGND Reference Ground for CI, RM 2 7 4 MDK Monitor Input 2 LDA CI (MD Cathode, Modulation) 3 6 5 MDA APC Setup, VCC AGND Monitor Input 1 (MD Anode) 4 5 6 VCC +2.4 to +6 V Supply Voltage MDA MDK 7 LDA Laser Supply (LD Anode) 8 LDK Driver Output (LD Cathode) PIN CONFIGURATION MSOP8 Do not short-circuit pins AGND and GND, for this may (top view) deteriorate the precision of the regulator and interfere with the soft-start 1 GND LDK CI LDA AGND VCC MDK MDA