ic-nzn N-TYPE LASER DIODE DRIVER

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1 Rev A, Page /6 FEATURES Peak value controlled laser diode driver for operation from CW up to 55 MHz Spikefree switching of laser currents of up to 300 ma Setting of laser power (APC) via external resistor Optional current control (ACC) Laser current limitation LVDS/ switching input with monitor output Low current consumption sleepmode < 50 µa Safety shutdown with overtemperature Error signal output with overtemperature, undervoltage and overcurrent All current LD types can be used (N/P/M configurations) Blue laser diodes supported Fast softstart Strong suppression of transients with small external capacitors APPLICATIONS Pulsed and CW laser diode modules Laser diode pointers Laser levels Barcode readers Distance measurement Blue laser diodes PACKAGES QFN24 4 mm x 4 mm BLOCK DIAGRAM V i()x540 R C 00 nf kΩ MONITOR icnzn N C 00 nf ma LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER R T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR R P suitable laser diode configurations N M P Copyright 200 ichaus

2 Rev A, Page 2/6 DESCRIPTION Laser diode pulse driver icnzn allows CW operation of laser diodes and spikefree switching with defined current pulses up to 55 MHz. The optical output power of the laser diode is setup by means of an external resistor (R/P). For laser current control without a monitor diode, the laser current monitor at pin is utilised. For high pulse frequencies the device can be switched into controlled burst mode. A previously settled operating point is maintained throughout the burst phase. An averaging current monitor can be set by means of an external resistor at pin. When the current limit is reached, overcurrent is signalled at and the current from pin is limited to the preset value but the ic is not shut down. There is an additional current limitation in pin that prevents the ic from overpowering the laser diode. Setting pin low, the ic enters a low consumption sleepmode (< 50 µa typ.). PACKAGES QFN24 4 mm x 4 mm to JEDEC PIN CONFIGURATION PIN FUNCTIONS No. Name Function NZN code Power Supply 2 Enable Averaging Control 3 APC setup, monitor input 4 Laser Current Monitor 5 D Enable Pulldown Current at 6 Positive LVDS/ switching input 7 Negative LVDS switching input 8 Enable input 9 Sync Output Supply Voltage 0 Sync Output R Reference Ground 2 R Reference (Ptype laser diodes) 3 Laser Diode Cathode 4 A Analog ground 5 S Power Control Capacitor sense 6 Power Control Capacitor 7 Laser Diode Anode 8 n/c 9 Current Monitor Setup 20 Control Enable 2 Ground 22 Not SleepMode 23 Error Output 24 n/c The Thermal Pad is to be connected to a Ground Plane () on the PCB. Only pin marking on top or bottom defines the package orientation ( to change). NZN label and coding is subject

3 Rev A, Page 3/6 ABSOLUTE MAXIMUM RATINGS Beyond these values damage may occur; device operation is not guaranteed. Item Symbol Parameter Conditions Unit No. Min. Max. G00 Voltage at V G002 I() Current in DC current ma G003 I() Current in V() = ma G004 I() Current in 2 20 ma G005 I() Current in 2 20 ma G006 I()dig Current in,,,,,, D 2 20 ma G007 I() Current in DC current ma G008 I() Current in DC current ma G009 I() Current in 2 20 ma G00 I() Current in NC 2 50 ma G0 I() Current in C 2 50 ma G02 I() Current in 2 20 ma G03 V()c Voltage at,,,,,,,, D, R,,,, R,,, V G04 V()h Voltage at V G05 Vd() ESD Susceptibility at all pins HBM, 00 pf discharged through.5 kω 4 kv G06 Tj Operating Junction Temperature C G07 Ts Storage Temperature Range C THERMAL DATA Operating Conditions: = V Item Symbol Parameter Conditions Unit No. Min. Typ. Max. T0 Ta Operating Ambient Temperature Range C T02 Rthja Thermal Resistance Chip/Ambient surface mounted, thermal pad soldered to ca. 2 cm² heat sink 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.

4 Rev A, Page 4/6 ELECTRICAL CHARACTERISTICS Operating Conditions: = V, = 0 V..., Tj = C, = hi, D = lo; unless otherwise stated Item Symbol Parameter Conditions Unit No. Min. Typ. Max. Total Device 00 Permissible Supply Voltage V 002 Permissible Supply Voltage at V 003 Ioff() Supply Current in = lo, all other input pins set to lo 5 50 µa 004 Idc() Supply Current in 680 Ω 0 5 ma 005 I() Supply Current in pin open 0 µa 006 Tab Thermal Shutdown Threshold C 007 on PowerOn Threshold V 008 Vc()hi Clamp Voltage hi at,,,,,,, I() = 0. ma, other pins open, = V 009 Vc()hi Clamp Voltage hi to at I() = ma, other pins open, = V 00 Vc()hi Clamp Voltage hi at I() = ma, other pins open 2 V 0 Vc()lo Clamp Voltage lo at,,,, D,,,,,, R, R,, A,,,,,, I() = ma, other pins open V 02 Vc()hi Clamp Voltage hi at,, I() = ma, other pins open, = 0 6 V Current Monitor, 0 V() Voltage at mv 02 Permissable Resistor at = V kω = V kω 03 V Voltage Monitor Threshold V(), V() = mv 04 Ierr() Maximum Unlimited current from without error signaling 05 Cmin() Minimum capacitor needed at V() = ; = V ma = V ma 00 nf 06 ri Current Ratio I()max / I() V() = 0 V = V = V ri Current Ratio I()max / I() V() = V() = V() = V() =, V() = 0 V = V = V i(ldk) Maximum limited current = 0.68 KΩ = 5.5 V 630 ma 09 Rdis() Discharge Resistor at = lo, V() = 20 kω Reference 20 V() V() V(R), V(R) V() for Ptype LD or ACC 202 dv() Temperature Drift of Voltage at closed control loop mv closed control loop 20 µv/ C 203 V() V() V(R) V() = 0 V, V() = 0 V, Ntype LD mv Digital Inputs/Outputs 30 Vin() Input Voltage Range at, = lo, = V Vd() Input Differential Voltage at, 303 R() Differential Input Impedance at, = lo, Vd() = V() V() 200 mv = lo kω V(), V() <.5 V 304 Vt()hi Input Threshold Voltage hi at = hi, = open 2 V 305 Vt()lo Input Threshold Voltage lo at = hi, = open 0.8 V V

5 Rev A, Page 5/6 ELECTRICAL CHARACTERISTICS Operating Conditions: = V, = 0 V..., Tj = C, = hi, D = lo; unless otherwise stated Item Symbol Parameter Conditions Unit No. Min. Typ. Max. 306 Vhys() Hysteresis at = hi, = open 40 mv 307 Ipd() PullDown Current at = hi, = open, V() = V µa 308 Vt()hi Input Threshold Voltage hi at,,,, D 309 Vt()lo Input Threshold Voltage lo at,,,, D 30 Vhys() Hysteresis at,,,, D 2 V 0.8 V mv 3 Ipu() PullUp Current at, V() = V 60 2 µa 32 Ipd() PullDown Current at,, D V() = V µa 33 Vs()hi Saturation voltage hi at Vs()hi = V(), I() = ma, =, = = High, = open 34 Vs()lo Saturation voltage lo at I() = ma, = High, =, = Low, = open 35 Isc()hi Shortcircuit Current hi at = = High, = open, V() = 0 V, = 36 Isc()lo Shortcircuit Current lo at = = High, = open, V() = 0 V, = 0.4 V 0.4 V 40 3 ma 3 25 ma 37 I() Current in V() > 0.6 V, error 20 ma 38 Vs()lo Saturation Voltage lo at I() = ma, error 600 mv Laser Driver,, 40 Vs()lo Saturation Voltage lo at I() = 300 ma, = 680 Ω, = V V I() = 00 ma, = 680 Ω = V.2 2 V I() = 60 ma, = 2.5 kω = V V 402 Idc() Permissible DC Current in 300 ma 403 Vo() Permissible Voltage at 2 V 404 C() Required Capacitor at 0 0 nf 405 I() Charge Current from ic active, = hi, V() = V, D = 0 V 0 µa ic active, = hi, V() = V, D = µa 406 Ipd() PullDown Current in ic active, = lo, D = hi, V() = V, = V 407 Imon() Current at V() = 0.5 V, I() < 300 ma, = V 408 Imin() Minimum permissible current pulse 409 Imax() Maximum obtainable current from the driver Timing 50 twu Time to Wakeup: lo hi to system enable µa /280 /200 I() 0.5 ma V() = V() = V() =, V() = 0 V; = V 300 ma = V 90 ma C = µf, = 680 Ω 300 µs 502 tr Laser Current Rise Time = 5 V see Fig. 2.5 ns 503 tf Laser Current Fall Time = 5 V see Fig. 2.5 ns 504 tp Propagation Delay V(x, x) I(x) = 5 V 0 ns

6 Rev A, Page 6/6 ELECTRICAL CHARACTERISTICS: DIAGRAMS I(LED) t r t f V 0.45V Vt()hi Input/Output I pk 90% I pk Vt()lo 0.45V 0 t 0% I pk t Figure : Reference levels Figure 2: Laser current pulse

7 Rev A, Page 7/6 DESCRIPTION OF FUNCTIONS icnzn is a laser diode pulse driver. The device features the following functions: Peak or averaging control Optical power (APC) or current control (ACC) Pulses of up to 55 MHz in controlled burst mode Laser current limitation Extension of the laser current with few external components Operation of blue laser diodes possible Error signalling for overcurrent Sleep mode with less than 50 µa consumption OPTICAL POWER CONTROL The icnzn supports the control of the laser diode s optical output power for all common laser diode pin configurations (N, P and M). The control is enabled with pin set to high. With set to low, the peak power control is enabled. The laser power level is selected by means of the resistor RMON (= R P). This control mode can be used for frequencies up to ca. 4 Mhz. For higher frequencies the averaging control ( = high) or the burst mode have to be used. Tables 4 and 5 show how to set the inputs for laser control depending on the input interface selected ( or LVDS). Laser control in mode ( = high/open) Mode low/open Powersave mode low/open open high low charged, laser off high open high high/open high charged, laser on, peak control high open high low high charged, laser on, burst mode Table 4: Laser control in mode Laser control in LVDS mode ( = low) Mode low/open Powersave mode < > high low charged, laser off > < high high/open high charged, laser on, peak control > < high low high charged, laser on, burst mode Table 5: Laser control in LVDS mode RMON dimensioning Peak control ( = low): In order to calculate the right value of RMON, the value of IM (monitor current with respect to optical output power) of the laser diode must be known. RMON must be chosen in a way that the monitor current generated by the desired output power creates a voltage drop across RMON of 500 mv (cf. Electrical Characteristics No. 20). Averaging control ( = high): In this mode the calculation is the same as in peak control, only the result has to be divided by the duty cycle of the laser pulses, D = τ T. At a duty cycle of e.g. 50% D = 2. This requires an external averaging capacitor of sufficient size at pin though. Control modes Averaging Operation mode RMON calculation = 0 Peak control RMON = V () IM = Averaging control RMON = V () IM D Table 6: RMON dimensioning Example By way of example, an output level of mw is to be set. With an optical power of mw e.g. laser diode HL6339G has a typical monitor current (IM) of 5 µa. The following value is then obtained for the resistor at pin (RMON = P R, where R is a fixed resistor and P a potentiometer.):

8 Rev A, Page 8/6 RMON = V () IM = 0.5 V 5 µa = kω External capacitor mode In applications where an external capacitor is required (see best performance recommendations below), the external capacitor mode must be enabled (pin D = high). This connects the capacitor to the control circuit and additionally enables a pulldown current at pin to prevent this capacitor from being charged due to residual currents (cf. Electrical Characteristics No. 406). Best performance recommendations The operating point for the laser diode is stored in an onchip capacitor. This permits a fast startup but can lead to an unstable control circuit under certain conditions such as inadequate PCB layout or laser diodes with very low monitor current. In these cases, an optional capacitor can be connected as close as possible to the chip, across pin and S. This will prevent instability of the control circuit. For averaging control a 0 nf capacitor at is recommended. Special care must be taken in PCB layout when laying out the path from the laser diode s cathode via pin to A. This path must be kept as short as possible to avoid parasitic inductances. A small 300 pf capacitor across the laser diode helps to compensate for these parasitic inductances. Figures 3, 4 and 5 show the typical setup for the different N, P and Mtype diode configurations. Ntype diodes V i()x540 R C 00 nf kΩ MONITOR icnzn N C 00 nf ma LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER R T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR R P Figure 3: Circuit example for Ntype laser diodes Ptype diodes Althought this kind of laser diodes are supported by ic NZN, it s strongly recommended to use icnzp instead since in this configuration, all the pulses at will be coupled directly to pin due to monitor diode s internal capacitance, thus making an accurate control much more difficult. Moreover, applications with Ptype laser diode case grounded are possible with icnzp only.

9 Rev A, Page 9/ V i()x540 R P R C 00 nf.. MONITOR icnzn C 00 nf.. P kΩ..300mA LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR R Figure 4: Circuit example for Ptype laser diodes. Mtype diodes V i()x540 R C 00 nf.. MONITOR icnzn M C 00 nf kΩ..300mA LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER R T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR R P Figure 5: Circuit example for Mtype laser diodes Althought this type of laser diode are supported by ic NZN, it s strongly recommended to use icnzp instead since in this configuration, all the pulses at will be coupled directly to pin due to monitor diode s internal capacitance, thus making an accurate control much more difficult. Moreover, applications with M type laser diode case grounded are possible with ic NZP only.

10 Rev A, Page 0/6 LASER CURRT LIMITATION i()x540 C current limitation icnzn monitors the average laser current flowing from pin (Figure 6). The DC current limit is set by means of a resistor at pin. 00 nf.. 0.5V 0.5V 00 nf.. When dimensioning resistor the following applies (cf. Electrical Characteristics No. 06): kω I max () = V The current limitation can be disabled by connecting pin to. Overcurrent Short pulses at with higher currents are possible as only the DC current is monitored and capacitor C supplies the current for short pulses. Figure 6: icnzn current limitation icnzn features two different current limitations, limiting the average current flowing from pin plus the current flowing into pin. current limitation The control circuit also monitors the laser current in pin and limits this current when reaching the threshold also defined by. The following applies (cf. Electrical Characteristics No. 07): I max ( ) = V BURST MODE In controlled burst mode icnzn can pulse with up to 55 MHz. Controlled here means that a preset operating point is maintained during the burst phase. Therefore an operating point is settled first, for which pin has to be high and the laser diode must be switched on. Once the operating point has been reached the laser diode can be switched off again. The operating point is stored in an onchip capacitor and when pin is set to low, the burst mode is activated. The preset operating point is maintained. For a longer burst mode, an external capacitor can be connected to pin. To prevent the laser current from rising due to residual currents, the capacitor is discharged then with a maximum of 50 na (cf. Electrical Characteristics No. 406). As the capacitor is discharged gradually, the output level must be resettled again after a certain period, depending on the admissible degradation of the laser output power.

11 Rev A, Page /6 CURRT CONTROL The icnzn also supports laser current control, when no monitor diode is present. For that purpose, a fraction of the current flowing trough the laser diode is provided at pin (I / 240, cf. Electrical Characteristics No. 407). Tables 7 and 8 show how to set the inputs for laser control depending on the input interface selected ( or LVDS). Laser control in mode ( = high/open) Mode low/open Power save mode low/open open high low charged, laser off high open high high/open high charged, laser on, regulated high open high low high charged, laser on, burst mode Table 7: Laser control in mode Laser control in LVDS mode ( = Low) Mode low/open Power save mode < > high low charged, laser off > < high high/open high charged, laser on, regulated > < high low high charged, laser on, burst mode Table 8: Laser control in LVDS mode The laser current is set by means of resistor RMON (= R P). Figure 7 shows the typical setup for current control. Control modes Averaging Operation mode RMON calculation = 0 Peak current control RMON = = Averaging control RMON = Table 9: Current control setup V (R) V () IM V (R) V () IM D External capacitor mode In applications where an external capacitor is required (see best performance recommendations below), the external capacitor mode must be enabled (pin D = high). This connects the capacitor to the control circuit and additionally enables a pulldown current at pin to prevent this capacitor from being charged due to residual currents (cf. Electrical Characteristics No. 406). Best performance recommendations The operating point for the laser diode is stored in an onchip capacitor. This permits a fast startup but can make the regulated system unstable under certain conditions such as inadequate PCB layout. In these cases, an optional capacitor can be connected as close as possible to the chip, across pins and S. For averaging control a 0 nf capacitor at pin is recommended. Special care must be taken in PCB layout when laying out the path from the laser diode s cathode via pin to A. This path must be kept as short as possible to avoid parasitic inductances. A snubber network across the laser diode also helps to compensate for these parasitic inductances.

12 Rev A, Page 2/ V i()x540 R P R C 00 nf.. MONITOR icnzn C 00 nf kΩ..300mA LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR Figure 7: Example setup for current control BLUE LASER DIODES With the icnzn also blue laser diodes can be driven. Due to the high forward voltage of these laser diodes, an appropriate supply voltage must be provided. The current limitation at pin cannot be used then, since only pin is capable of handling the higher voltage required for the blue laser diodes. Nevertheless, the current limitation protection in pin LKD (cf. Electrical Characteristics No. 07) is still active. Figure 8 shows a typical setup for blue laser diodes with APC and figure 9 with ACC...2V CL V i()x540 R M 00 nf.. C 00 nf.. MONITOR icnzn kΩ..300mA LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER R T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR R P Figure 8: Setup for blue laser diodes with APC

13 Rev A, Page 3/6..2V CL V i()x540 R P R 00 nf.. C 00 nf.. MONITOR icnzn kΩ..300mA LVDS/ REF x240 E S A..0 nf.. D E INPUT INTERFACE OUTPUT DRIVER T.PAD OverCurrent Low V() Bandgap, Reference, Overtemp OUTPUT MONITOR R Figure 9: Setup for blue laser diodes with ACC SLE MODE The icnzn has a very low consumption sleep mode, e.g. for battery powered applications. With pin set to low the chip enters the sleep mode and disconnects pin from the supply. The wakeup time from this sleep mode is about 300 µs.

14 Rev A, Page 4/6 EVALUATION BOARD icnzn comes with an evaluation board for test purpose. Figures 0 and show both the schematic and the component side of the evaluation board. JV5D 6 J J 2 J2 4 J3 5 J4 8 J5 0 J6 2 J 3 JLVDS_P 9 JP2 JLVDS_N JP C 00nF C2 opt R3 k D3 RD D 2 JP5 JP4 ILIM OFF R2 2.74k C7 00nF JP6 JP7 JP8 Cext ON R4 opt JP9 JP0 BURST LVDS U icnzn 2 7 D 5 i()x540 MONITOR LVDS/ INPUT INTERFACE OverCurrent Low V() icnzn REF x240 OUTPUT DRIVER Bandgap, Reference, Overtemp OUTPUT MONITOR SUB AD R S 5 A 4 3 R JP3 (default) R7 opt 2 D LDC 3 C8 opt C5 0nF C6 opt S JP2 (default) ACC APC 2 3 R 5.K R5 opt R C L 0K P JP NType MType (default) 2 3 PType ACC A N R6 opt 3 LDC C 2 LDC A 2 3 P M D2 C3 00nF C4 opt Figure 0: Schematic of the evaluation board

15 Rev A, Page 5/6 Figure : Evaluation board (component side) ichaus expressly reserves the right to change its products and/or specifications. An Infoletter gives details as to any amendments and additions made to the relevant current specifications on our internet website this letter is generated automatically and shall be sent to registered users by . Copying even as an excerpt is only permitted with ichaus approval in writing and precise reference to source. ichaus 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. ichaus conveys no patent, copyright, mask work right or other trade mark right to this product. ichaus 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 (HannoverMesse). We understand suitable application of our published designs to be stateoftheart 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.

16 Rev A, Page 6/6 ORDERING INFORMATION Type Package Order Designation icnzn QFN24 4 mm x 4 mm icnzn QFN24 Evaluation Board icnzn EVAl NZND For technical support, information about prices and terms of delivery please contact: ichaus GmbH Tel.: 49 (6 35) Am Kuemmerling 8 Fax: 49 (6 35) D55294 Bodenheim Web: GERMANY sales@ichaus.com Appointed local distributors:

ic-nzn N-TYPE LASER DIODE DRIVER

ic-nzn N-TYPE LASER DIODE DRIVER NTYPE LASER DIODE DRIVER Rev D, Page /6 FEATURES Peak value controlled laser diode driver for operation from CW up to 55 MHz Spikefree switching of laser currents of up to 300 ma Setting of laser power