iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 1/10 FEATURES APPLICATIONS ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Transmitter for laser light barriers from 1 to 200 kHz Laser diode driver of up to 250 mA Averaging control of laser power Protective functions to prevent destruction of laser diode Laser-current monitor with current or voltage output Integrated RC oscillator up to 4 MHz Integrated 16:1 divider for pulse generation in the kHz range Stable 1:1 pulse duty ratio Simple adjustment of the laser power via external resistor Soft-start at power-on Complementary pulse repetition frequency output for ECL level Shutdown in case of overtemperature Single 5 V power supply Very few external components iC-VJ for laser diodes with 50 to 500 µA monitor current iC-VJZ for laser diodes with 0.15 to 1.5 mA monitor current PACKAGES SO16N BLOCK DIAGRAM DC−Monitor Sync 5V R3 10kΩ C3 100nF 4 13 MO 12 MI C4 100 µF VCC OUTPUT DRIVER DIVIDER 14 Q PRF 1 16:1 NQ NQ 15 AMD 1 KLD 2 GND 3 MD LD NPRF 4 MONITOR 7 2 1:1 iC−VJ 1:3 iC−VJZ OSCILLATOR POWER ON TH−SHUTDOWN REFERENCE 3 5 R ISET RC 5 6 iC−VJ/VJZ RSET 10kΩ R1 800Ω AGND CI 11 6 9 7 C2 100nF..470nF usable LD models C1 100pF Copyright © 2006 iC-Haus http://www.ichaus.com iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 2/10 DESCRIPTION The devices iC-VJ and iC-VJZ are control ICs for laser diodes. Control to the average of the laser current and integrated protective functions ensure save operation of the sensitive semiconductor laser. All required functions for the pulse operation of a CW laser are integrated: a power driver and monitor amplifier for direct connection of the laser diode, an oscillator for pulse repetition frequency generation, a start-up and temperature protection as well as monitor and pulse repetition frequency outputs for synchronous control of a receiver circuit. The laser power control is adapted to the laser diode used with an external resistor at ISET. The capacitor at CI determines the control time constants. The oscillator operates with an external RC circuit in the range from about 10 kHz to 4 kMHz. The gener- ated pulse duty factor is a stable 1:1; the oscillator frequency is reduced to 1/16th by the integrated divider. An image of the laser diode current is output via MI. Output MI when connected with a low pass filter forms a voltage proportional to the average laser current. This voltage is output to MO via the integrated voltage follower and is thus available for any applications. The Outputs PRF and NPRF supply the pulse repetition frequency complementarily to analogue levels (VCC / 2 ±0.75 Vpk ) to be able to activate high-speed ECL logic of a receiver circuit. The IC contains protective diodes against ESD destruction, a thermal shutdown, plus a start-up circuit for the laser diode driver to protect the laser diode when the supply voltage is switched on. PACKAGES SO16N to JEDEC Standard PIN CONFIGURATION SO16N (top view) 1 PIN FUNCTIONS No. Name Function 16 AMD n.c. 3 GND 4 MI 5 R 6 RC iC−VJ# Code... ... ...yyww 2 KLD 15 NPRF 14 PRF 13 MO 12 VCC 11 ISET 7 10 8 9 n.c. AGND n.c. CI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 AMD KLD GND MI R RC AGND n.c. CI n.c. ISET Anode Monitor Diode Cathode Laser Diode Ground Monitor Current Output Oscillator Resistor Oscillator Capacitor Analogue Ground Averaging Capacitor Set-up Resistor for the Laser Diode Power VCC 5 V Supply Voltage MO Monitor Voltage Output PRF Pulse Repetition Frequency Output NPRF Inverted PRF n.c. iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 3/10 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 Supply Voltage 0 6 V G002 I(AGND) Current in AGND -4 4 mA G003 I(CI) Current in CI -4 4 mA G004 V(KLD) Voltage at KLD PRF = lo 0 6 V G005 I(KLD) G006 I(AMD) Current in KLD PRF = hi -4 600 mA Current in AMD iC-VJ iC-VJZ -4 -6 4 6 mA mA G007 I(PRF) Current in PRF -10 2 mA G008 I(NPRF) Current in NPRF -10 2 mA G009 I(R,RC) Current in R, RC -2 2 mA G010 I(ISET) Current at ISET -2 2 mA G011 I(MI) Current in MI -2 2 mA G012 I(MO) Current in MO -2 2 mA G013 Tj Junction Temperature -40 150 °C G014 Ts Storage Temperature -40 150 °C THERMAL DATA Operating Conditions: VCC = 5 V ±10% Item No. Symbol Parameter Conditions Fig. Unit Min. T01 Ta Operating Ambient Temperature Range (extended temperature range on request) T02 Rthja Thermal Resistance Chip to Ambient -25 soldered on PCB, without special cooling 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. Typ. Max. 90 °C 140 K/W iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 4/10 ELECTRICAL CHARACTERISTICS Operating Conditions: VCC = 5 V ±10%, RSET = 5...50 kΩ, iC-VJ: I(AMD) = 50...500 µA, iC-VJZ: I(AMD) = 0.15...1.5 mA; Tj = -25...125 °C, unless otherwise stated. Item No. Symbol Parameter Conditions Tj °C Fig. Unit Min. Typ. Max. Total Device 001 VCC Permissible Supply Voltage Range at VCC 4.5 002 Iav(VCC) Supply Current in VCC (average Iav(KLD) = 100 mA, value) fosc = 3.2 MHz ±20%, I(PRF, NPRF) = 0 003 tp(KLDPRF) Pulse Edge Delay I(KLD) to V(PRF) PRF(hi ↔ lo), I(50%):V(50%) 004 tp(KLDNPRF) Pulse Edge Delay I(KLD) to V(NPRF) NPRF(hi ↔ lo), I(50%):V(50%) 5.5 V 50 mA -70 70 ns -70 70 ns Driver KLD, AMD 101 Vs(KLD) Saturation Voltage at KLD PRF = hi, I(KLD) = 200 mA 1.5 V 102 I0(KLD) Leakage Current in KLD PRF = lo, V(KLD) = VCC 10 µA 103 I(KLD) Current in KLD I(AMD) = 0 250 104 V(AMD) Voltage at AMD iC-VJ: I(AMD) = 500 µA iC-VJZ: I(AMD) = 1.5 mA 0.5 105 tr Current Rise Time in KLD 106 tf 107 CR1()av 108 CR2() mA 1.5 V Imax(KLD) = 20...250 mA, I(KLD): 10% → 90% 150 ns Current Fall Time in KLD Imax(KLD) = 20...250 mA, I(KLD): 90% → 10% 150 ns Average Value for Current Ratio I(AMD) / I(ISET) I(CI) = 0, closed control loop; iC-VJ iC-VJZ 0.8 2.4 1 3 1.2 3.6 Current Ratio I(AMD) / I(CI) V(CI) = 1...3.5 V, ISET open; iC-VJ iC-VJZ 0.9 2.7 1 3 1.1 3.3 Output PRF, NPRF 201 Vav() Average Value of Output Voltage I(PRF, NPRF) = 0...-4 mA 47.5 50 52.5 %VCC 202 Vpk() Amplitude 625 750 875 mV 203 tpp() Pulse/Pause Ratio 0.95 1 1.05 204 j() Jitter VCC, fosc = const. 20 ns 205 tr() Rise Time CL() = 50 pF, V(): 10% → 90% 150 ns 206 tf() Fall Time CL() = 50 pF, V(): 90% → 10% 150 ns MHz I(PRF, NPRF) = 0...-4 mA Oscillator R, RC 301 fosc Oscillator Frequency R1 = 800 Ω, C1 = 100 pF 2.64 2.9 3.19 302 fosc/f0 Frequency Drift R × C = constant 0.85 1 1.15 Divider 401 Div Reference ISET 501 V(ISET) Division Factor fosc / PRF 16 Reference Voltage 1.20 27 502 CR() Current Ratio I(CI) / I(ISET) 503 RSET Permissible Resistor at ISET to AGND (Control Set-up Range) V(CI) = 1...3.5 V, I(AMD) = 0 1.27 1.22 0.9 2.7 1 V V 1.1 50 kΩ Power-on and Thermal Shutdown 601 VCCon Turn-on Threshold VCC 3.0 4.1 V 602 VCChys Hysteresis 300 450 mV 603 Toff Thermal Shutdown Threshold 125 150 °C 604 Thys Thermal Shutdown Hysteresis 10 605 Vs(CI)lo Saturation Voltage lo at CI in case of undervoltage VCC = 0...VCCon − VCChys, I(CI) = 300 µA °C 1.5 V iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 5/10 ELECTRICAL CHARACTERISTICS Operating Conditions: VCC = 5 V ±10%, RSET = 5...50 kΩ, iC-VJ: I(AMD) = 50...500 µA, iC-VJZ: I(AMD) = 0.15...1.5 mA; Tj = -25...125 °C, unless otherwise stated. Item No. 606 Symbol Vs(CI)hi Parameter Saturation Voltage hi at CI Conditions Tj °C Fig. Unit Min. Vs(CI)hi = VCC − V(CI), RSET = 25 kΩ; iC-VJ: I(AMD) = 30 µA iC-VJZ: I(AMD) = 90 µA 0.3 Typ. Max. V Monitor Outputs MI, MO 701 Iav(MI) Current in MI (Average Value) R(MI) = 10 kΩ, C(MI) = 100 nF, Iav(KLD) = 10...50 mA 0.15 0.19 0.23 % I(KLD) 702 Iav(MI) Current in MI (Average Value) R(MI) = 10 kΩ, C(MI) = 100 nF, Iav(KLD) = 50...125 mA 0.12 0.19 0.26 % I(KLD) 703 I0(MI) Leakage Current in MI PRF = lo, V(MI) = 0 V 704 Vos(MOMI) Offset Voltage V(MO − MI) V(MI) = 0.2...3.5 V, R(MO) = 5 kΩ -30 3 µA 30 mV iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 6/10 DESCRIPTION OF FUNCTIONS Laser Power Adjustment The iC-VJ and iC-VJZ devices can be adapted to CW laser diodes from 2 to 40 mW. Models can be used in which the cathode of the monitor diode is connected to the anode or the cathode of the laser diode. Example iC-VJ Laser diode with 5 mW maximum optical output, monitor diode with 0.13 mA/mW, average power 1 mW (peak power 2 mW; pulse duty ratio Twhi / T is 50%). RSET is calculated as: The driver output, pin KLD, permits laser diode currents of up to 250 mA. In the event of a thermal overload due to excessive high power dissipation, the driver is turned off. RSET = CR1 ∗ V (ISET ) 1 ∗ 1.22 V = ≈ 9.4 k Ω I(AMD) 0.13 mA with the Electrical Characteristics No. 501 for V(ISET) and with No. 107 for current ratio CR1. The pin ISET is used for the adjustment to the sensitivity of the monitor diode and to set the desired optical laser power. The setpoint for the average control of the monitor diode current is preset at this pin, by connecting it either to a resistor or a current source. Example iC-VJZ Laser diode with 5 mW maximum optical output, monitor diode with 0.75 mA at 3 mW, average power 1 mW (peak 2 mW; pulse duty ratio Twhi / T is 50%). When connected to a current source, by means of an operational amplifier with current output (OTA) for example, the laser power can also be modulated. In order to limit the current at pin ISET when turning on the supply for the OTA, however, the OTA output should be connected to the base point of RSET. For the average monitor current of 0.25 mA the resistor RSET is calculated as: RSET = The maximum current possible at ISET must be taken into consideration when dimensioning the capacitor C2. CR1 ∗ V (ISET ) 3 ∗ 1.22 V = ≈ 14.6 k Ω I(AMD) 0.25 mA with the Electrical Characteristics No. 501 for V(ISET) and with No. 107 (iC-VJZ) for current ratio CR1. DC−Monitor Sync 5V R3 10k Ω 13 C3 100nF 4 MO 12 MI DRIVER OUTPUT 14 C4 100 µF VCC Q DIVIDER 16:1 LD 1 PRF NQ 15 MD AMD NQ NPRF MONITOR 7 4 2 1:1 iC−VJ 1:3 iC−VJZ POWER ON TH−SHUTDOWN REFERENCE KLD OSCILLATOR 3 5 R RC ISET 5 6 11 RSET R1 800 Ω GND 6 iC−VJ/VJZ CI AGND 9 7 3 C2 470nF C1 100pF Figure 1: Operation of a laser diode according to the example iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 7/10 Oscillator The internal oscillator operates in the range approx. 10 kHz to 4 MHz. This enables laser pulse repetition frequencies from 1 to 200 kHz. Fig. 2 shows the pulse repetition frequency as a function of the oscillator circuit. PRF [1V/div] LASER Output [2mW/div] I(KDL) [50mA/div] KDL [1V/div] Timebase = 1:s/div Example R1 = 620 Ω, C1 = 82 pF: f ≈ 200 kHz Figure 3: Settled control with 200 kHz pulse repetition frequency f [kHz] 200 Turn-on and Turn-off Behavior Capacitor C2 also determines the starting time from switching on the supply voltage VCC to steady-state laser pulse operation. The values of C2 which are necessary higher for low pulse repetition frequencies increase this starting time to several milliseconds (Fig. 4). The following applies for estimating the starting time: 100 C1= 82pF C1= 220pF C1= 1nF 1 2 3 4 5 6 7 8 R1 [kΩ] Figure 2: Pulse repetition frequency Ton ≈ Averaging Control The control of the average optical laser power requires the external capacitor C2 at pin CI. This capacitor is used for averaging and must be adjusted to the selected pulse repetition frequency and the charging current preset with RSET. The ratios are linear in both cases, i.e. C2 must be increased in size proportionally as the pulse repetition frequency slows or resistance RSET decreases. 2.5 V ∗ C2 2.5 V ∗ C2 ∗ RSET = I(ISET ) 1.22 V Example C2 = 4.7 µF, RSET = 10 kΩ: Ton ≈ 96 ms VCC [2V/div] PRF [2V/div] LASER Output [2mW/div] C2 ≥ 440 ∗ I(ISET ) 440 = f ∗ V (ISET ) f ∗ RSET C [1V/div] Timebase = 20 ms/div Example Frequency 10 kHz, RSET = 10 kΩ: C2 ≈ 4.7 µF Figure 4: Turn-on behavior f = 10 kHz, RSET = 10 kΩ, C2 = 4.7 µF LASER Output Otherwise the charging of C2 during the pulse pauses (with I(ISET) = 1.22 V / RSET) will result in excessive mean value potential at pin CI and the laser diode may be destroyed with the next pulse. C2 is correctly dimensioned when the current through the laser diode and the optical output signal do not show any overshooting on the rising edge. In steady-state condition, signals will then appear at the IC pins as shown in Fig. 3. In this case the laser pulse exhibits a minimal overshoot on the rising edge, but this can be tolerated. The increase in the current in KLD and the laser pulse follow directly after the signal at the divider output PRF. The outputs PRF and NPRF are used for receiver synchronisation. LASER Output [1mW/div] C [200mV/div] Figure 5: Setteling of the averaging control For high pulse repetition frequencies (200 kHz) and low C2 values (220 nF) and for RSET = 10 kΩ the averaging control achieves its operating point after 3.5 ms. Fig. 5 shows the turn-on, Fig. 6 the turn-off behavior, here in case of undervoltage. iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 8/10 up transients (Fig. 7). This capacitor should be placed close to the laser diode and not at the start of the LD supply line. VCC [2V/div] LASER Output [1mW/div] Figure 6: Turn-off behavior An approx. 12 Ω series resistor at pin KLD reduces the iC power consumption and damps possible resonances of the load circuit caused by the inductive LD supply line. This resistor is useful for many applications, also for those which do not operate via cable. Operation of a laser diode via cable It is recommended to connect a capacitor from 1 nF up to 10 nF across the laser diode in order to protect the laser diode against destruction due to ESD or build- When the LD supply line is laid out on the PCB, the forward path VCC should be arranged in parallel with, i.e. be close to the return path to KLD, even when the line is only a few centimeters in length. C [50mV/div] Sync 5V DC−Monitor R3 10kΩ 13 4 C4 100µF 12 MI MO VCC DRIVER OUTPUT 14 C3 100nF DIVIDER Q 16:1 LD 1 PRF NQ 15 NQ AMD 1 KLD 2 MD MONITOR NPRF 7 4 2 1:1 iC−VJ 1:3 iC−VJZ POWER ON TH.− SHUTDOWN REFERENCE R5 12Ω OSCILLATOR 3 5 R RC ISET 5 6 11 R1 800Ω RSET GND 6 iC−VJ/VJZ CI 9 3 AGND 7 C2 470nF C1 100pF Figure 7: Operation of a laser diode via cable C5 5nF iC-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 9/10 EVALUATION BOARD For the devices iC-VJ/VJZ a Demo Board is available for test purposes. The following figures show the schematic diagram and the component side of the test PCB. J1 ALD VCC C4 100uF C5 2nF MD LD AMD R5 12Ω KLD GND 1 AMD 2 KLD 3 MI GND NPRF MI 5 R3 10kΩ R1 680Ω AGND 7 VCC R RC REF 13 MO 12 RMOD 10kΩ (15kΩ) 11 ISET IMOD AGND CI iC−VJ/ VJZ C1 82pF PRF MO OSC 6 14 PRF 4 C3 100nF NPRF 15 9 C2 470nF C6 100nF RSET 10kΩ (15kΩ) Figure 8: Schematic diagram of the Demo Board Figure 9: Demo Board (components side) 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-VJ, iC-VJZ LASER DIODE CONTROLLER Rev A1, Page 10/10 ORDERING INFORMATION Type Package Order Designation iC-VJ Demo Board SO16N iC-VJ SO16N iC-VJ EVAL VJD iC-VJZ Demo Board SO16N iC-VJZ SO16N iC-VJZ EVAL VJD 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]