INTEGRATED CIRCUITS DATA SHEET OQ8844 Digital Servo Driver (DSD-2) Product specification File under Integrated Circuits, IC01 1995 Nov 27 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 FEATURES GENERAL DESCRIPTION Servo functions The OQ8844 or Digital Servo Driver 2 (DSD2) consists of 1-bit class-D power drivers, which are specially designed for digital servo applications. Three such amplifiers are integrated in one chip, to drive the focus and radial actuators and the sledge motor of a compact disc optical system. • 1-bit class-D focus actuator driver (3.3 Ω) • 1-bit class-D radial actuator driver (3.7 Ω) • 1-bit class-D sledge motor driver (2.5 Ω). Other features The main benefits of using this principle are its higher efficiency grade compared to conventional analog power amplifiers, its higher integration level, its differential output and the fact that only a few external components are needed. When using these digital power drivers in a digital servo application, the statement ‘complete digital servo loop’ becomes more realistic. • Supply voltage 5 V only • Small package (SOT163-1) • Higher efficiency, compared with conventional drivers, due to the class-D principle • Built-in digital notch filters for higher efficiency • Enable input for focus and radial driver • Enable input for sledge driver • Differential outputs for all drivers • Separate power supply pins for all drivers. QUICK REFERENCE DATA SYMBOL PARAMETER MIN. TYP. MAX. UNIT VDDD digital supply voltage 4.5 − 5.5 V VDD(F) supply voltage focus actuator 4.5 − 5.5 V VDD(R) supply voltage radial actuator 4.5 − 5.5 V VDD(S) supply voltage sledge actuator 4.5 − 5.5 V IDDDq quiescent supply current digital part − − 10 µA IDD(F) supply current focus − 126 250 mA IDD(R) supply current radial − 20 250 mA IDD(S) supply current sledge − 150 560 mA fi(clk) input clock frequency − 4.2336 5 MHz Ptot total power dissipation − 110 − mW Tamb operating ambient temperature −40 − +85 °C ORDERING INFORMATION PACKAGE TYPE NUMBER NAME OQ8844 SO20 1995 Nov 27 DESCRIPTION plastic small outline package; 20 leads; body width 7.5 mm 2 VERSION SOT163-1 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 BLOCK DIAGRAM VDDD VDD(R) VDD(F) VDD(S) 6 RAC 4 13 14 1 DIGITAL NOTCH FILTER ENDSTAGE H−BRIDGE DIGITAL NOTCH FILTER ENDSTAGE H−BRIDGE DIGITAL NOTCH FILTER ENDSTAGE H−BRIDGE 11 12 RA+ RA− OQ8844 FOC SLC CLI EN1 EN2 3 2 15 16 19 20 7 8 CONTROL 9 5 10 17 18 MBG785 VSSD VSS(R) VSS(F) Fig.1 Block diagram. 1995 Nov 27 3 VSSS FO+ FO− SL+ SL− Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 PINNING SYMBOL PIN DESCRIPTION VDD(S) 1 supply voltage for sledge motor driver SLC 2 PDM input for sledge driver FOC 3 PDM input for focus driver RAC 4 PDM input for radial driver VSSD 5 digital ground VDDD 6 digital supply voltage CLI 7 clock input EN1 8 enable input 1 EN2 9 enable input 2 VSS(R) 10 radial driver ground RA+ 11 RA− 12 VDD(R) 13 radial supply voltage VDD(F) 14 focus supply voltage FO+ 15 focus driver (positive output) FO− 16 focus driver (negative output) VDD(S) 1 20 SL− SLC 2 19 SL+ FOC 3 18 VSSS RAC 4 17 VSS(F) VSSD 5 16 FO− OQ8844 VDDD 6 15 FO+ CLI 7 14 VDD(F) radial driver (positive output) EN1 8 13 VDD(R) radial driver (negative output) EN2 9 12 RA− VSS(R) 10 11 RA+ VSS(F) 17 focus ground VSSS 18 sledge driver ground SL+ 19 sledge driver (positive output) SL− 20 sledge driver (negative output) 1995 Nov 27 handbook, halfpage MBG784 Fig.2 Pin configuration. 4 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 half the sample frequency of 1.0584 MHz. This results in a high dissipation and the motor does not move. FUNCTIONAL DESCRIPTION Principle of a class-D digital power driver To improve the efficiency, a digital notch filter is added at the input of the digital drivers. This filters the Idle mode pattern (1010101010 etc.) see Fig.6. Figure 3 shows the block diagram of one of the digital drivers integrated in the DSD2. It consists of a timing block and four CMOS switches. The input signal is a 1-bit Pulse Density Modulated (PDM) signal, the output of the digital servo ICs. The amplitude transfer as a function of frequency is given in Fig.7. Figure 7 shows that the filter has a zero on 1⁄2fs, consequentially filtering out the idle pattern (101010). The output of this filter is a three-level code (1.5-bit). For the control of the switches three states (1.5-bit) can be distinguished: the two states as described earlier and a third one. This state is used when an idling pattern is supplied. The maximum operating clock frequency of the device is 5 MHz. With the mentioned digital servo ICs, the operating frequency of the digital drivers is 4.2336 MHz (96 × 44.1 kHz). The sampling frequency of the 1-bit code however is 1.0584 MHz, so internally in the DSD2 the clock speed of the switches will be 1.0584 MHz. The higher input clock frequency is used to make non-overlapping pulses to prevent short-circuits between the supply voltages. For the control of the switches, two states can be distinguished. If the 1-bit code contains a logic 1, switches A and D are closed and current will flow in the direction as shown in Fig.4. Switches C and D are closed (see Fig.8). In this idle mode, no current will flow and thus the efficiency will be improved. This mode is also used to short-circuit the inductive actuator/motor. In this way, high induction voltages are prevented because the current can commutate via the filter and the short-circuit in the switches. All three drivers (radial, focus and sledge) contain a digital notch filter as described. Each driver has its own power supply pins to reduce crosstalk because of the relative high current flowing through the pins. If the 1-bit code contains a logic 0, switches B and C are closed and current will flow in the opposite direction, as shown in Fig.5. This indicates that the difference between the mean number of ones and zeros in the PDM signal determines the direction in which the actuator or motor will rotate. If the mean number of ones and zeros is equal (Idle mode) the current through the motor or actuator is alternated between the positive and negative direction at a speed of 1995 Nov 27 5 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 VDD VDD Ipos A B 1-bit code '1' 1-bit code (1) TIMING (1) M TIMING M clock clock C MBG786 MBG787 VSS (1) Sledge motor; focus/radial motor. D VSS (1) Sledge motor; focus/radial motor. Fig.3 One of the digital drivers. Fig.4 1-bit code is logic 1. VDD Ineg A B 1-bit code '0' 1-bit (1) clock MBG789 C MBG788 D VSS The filter consists of a simple delay element (flip-flop) and an adder. The transfer from input-to-output is: H(z) = 1 + z−1. (1) Sledge motor; focus/radial motor. Fig.5 1-bit code is logic 0. 1995 Nov 27 1.5-bit 1/Z M TIMING Fig.6 Notch filter at input of digital drivers. 6 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 MBG790 |H| VDD A B 1-bit code 'idle' (1) M TIMING clock C D Iidle 1/2fs MBG791 VSS (1) Sledge motor; focus/radial motor. Fig.7 Amplitude transfer. Fig.8 Idling pattern. The switching of the outputs occurs in a similar way, except that in this event the negative edge of CLI is used. In this way, the input signals are immune to the noise radiated by the switching of the outputs. It is possible that an output transition will have a noticeable effect on the power supply voltage or the ground voltage. To avoid simultaneous transitions of all outputs, the outputs of each bridge are also clocked at a different phase of CLI. Consequentially there are only 3 out of 4 negative edges effective. Switches The digital part of the power drivers consists of standard cells. The power switches are specifically designed for CD applications. The most important feature is their on-resistance. In the applications, they have to drive very low-ohmic actuators and/or motors. The switches are designed to have an on-resistance of 2 Ω for the actuator drivers and 1 Ω for the sledge motor driver. In any mode, there are always two switches in series with the actuator/motor. The total loss due to the switches is 4 Ω for the actuators and 2 Ω for the sledge motor. To reset the circuit, both the reset condition and the clock should be present, because all flip-flops are reset synchronously. The clock signal is also required to obtain one of the possible modes of operation indicated in Table 1. Timing of input and output signals All internal timing signals are derived from the externally supplied CLI signal. Sampling of the data inputs (SLC, FOC and RAC) occurs at a frequency of 1⁄4CL. For each channel, the clocking-in occurs at a different positive edge of CLI. Because there are only 3 channels, and the clock frequency CLI is divided-by-4, only 3 out of 4 positive edges are effective for sampling one of the inputs. 1995 Nov 27 7 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) Table 1 OQ8844 Possible modes of operation EN1 EN2 SLEDGE DRIVER FOCUS/RADIAL DRIVER 0 0 off off standby 0 1 off on partly operating 1 0 off off reset 1 1 on on operating MODE The timing diagram as shown in Fig.9 gives the relation between the different clocks. The negative edge of the signals called nc10 to nc12 is used to process the incoming data (see Table 2). The negative edge of all signals called c10s to c12s is used to trigger the outputs (see Table 2). Table 2 Signals nc10 to nc12 and c10s to c12s SIGNAL DESCRIPTION ncl0 sledge input sampling clock ncl1 focus input sampling clock ncl2 radial input sampling clock cl0s sledge output trigger clock cl1s focus output trigger clock cl2s radial output trigger clock LIMITING VALUES In accordance with the Absolute Maximum Rating System (IEC 134). SYMBOL PARAMETER MIN. MAX. UNIT VDDD digital supply voltage −0.5 +6.5 V VDDA analog supply voltage −0.5 +6.5 V VSSD − VSSA ground supply voltage difference −5 +5 mV Ptot total power dissipation − 730 mW Tstg storage temperature −55 +150 °C Tamb operating ambient temperature −40 +85 °C THERMAL CHARACTERISTICS SYMBOL Rth j-a 1995 Nov 27 PARAMETER thermal resistance from junction to ambient in free air 8 VALUE UNIT 75 K/W Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 CHARACTERISTICS VDDD = VDDA = 5 V; VSSD = VSSA = 0 V; Tamb = 25 °C; unless otherwise specified. SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT 4.5 − 5.5 supply voltage analog part 4.5 − 5.5 V quiescent supply current digital part − − 10 µA note 1 − 126 250 mA maximum supply current radial note 1 − 20 250 mA maximum supply current sledge note 1 − 150 560 mA input clock frequency − 4.2336 5 MHz Ptot totalpower dissipation − 110 − mW Tamb operating ambient temperature −40 − +85 °C VDDD supply voltage digital part VDDA IDDDq IDD(F)max maximum supply current focus IDD(R)max IDD(S)max fi(clk) V Digital inputs; SLC, FOC, RAC, CLI, EN1 and EN2 VIL LOW level input voltage Tamb = −40 to 85 °C − − 0.2VDDD V VIH HIGH level input voltage Tamb = −40 to 85 °C 0.8VDDD − − V ILI input leakage current − − 1 µA − 4.2336 5 MHz − − 250 mA − 3.3 4.1 Ω − − 250 mA − 3.7 4.6 Ω − − 560 mA − 2.5 3.1 Ω Clock input; CLI fclk clock frequency Analog outputs; FO+ and FO− IO output current RO output resistance note 2 Analog outputs; RA+ and RA− IO output current RO output resistance note 2 Analog outputs; SL+ and SL− IO output current RO output resistance note 2 Notes V DDA max 1. Maximum supply current depends on the value of RL: I max = --------------------------( RO + RL) 2. Output resistance is defined as the series resistance of the complete bridge. 1995 Nov 27 9 FOC RAC ncI0 ncI1 ncI2 Philips Semiconductors SLC inputs Digital Servo Driver (DSD-2) Timing diagram full pagewidth 1995 Nov 27 CLI cI0s cI1s 10 cI2s SL+ SL− FO+ outputs FO− RA+ RA− MBG792 Product specification Fig.9 Timing diagram. OQ8844 Sampling of the incoming data is marked by a ‘∗’. Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 PACKAGE OUTLINE SO20: plastic small outline package; 20 leads; body width 7.5 mm SOT163-1 D E A X c HE y v M A Z 11 20 Q A2 A (A 3) A1 pin 1 index θ Lp L 1 10 e bp detail X w M 0 5 10 mm scale DIMENSIONS (inch dimensions are derived from the original mm dimensions) UNIT A max. A1 A2 A3 bp c D (1) E (1) e HE L Lp Q v w y mm 2.65 0.30 0.10 2.45 2.25 0.25 0.49 0.36 0.32 0.23 13.0 12.6 7.6 7.4 1.27 10.65 10.00 1.4 1.1 0.4 1.1 1.0 0.25 0.25 0.1 0.9 0.4 inches 0.10 0.012 0.096 0.004 0.089 0.01 0.019 0.013 0.014 0.009 0.51 0.49 0.30 0.29 0.050 0.419 0.043 0.055 0.394 0.016 0.043 0.039 0.01 0.01 0.004 0.035 0.016 Z (1) θ 8o 0o Note 1. Plastic or metal protrusions of 0.15 mm maximum per side are not included. REFERENCES OUTLINE VERSION IEC JEDEC SOT163-1 075E04 MS-013AC 1995 Nov 27 EIAJ EUROPEAN PROJECTION ISSUE DATE 95-01-24 97-05-22 11 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 SOLDERING Wave soldering Introduction Wave soldering techniques can be used for all SO packages if the following conditions are observed: There is no soldering method that is ideal for all IC packages. Wave soldering is often preferred when through-hole and surface mounted components are mixed on one printed-circuit board. However, wave soldering is not always suitable for surface mounted ICs, or for printed-circuits with high population densities. In these situations reflow soldering is often used. • A double-wave (a turbulent wave with high upward pressure followed by a smooth laminar wave) soldering technique should be used. • The longitudinal axis of the package footprint must be parallel to the solder flow. • The package footprint must incorporate solder thieves at the downstream end. This text gives a very brief insight to a complex technology. A more in-depth account of soldering ICs can be found in our “IC Package Databook” (order code 9398 652 90011). During placement and before soldering, the package must be fixed with a droplet of adhesive. The adhesive can be applied by screen printing, pin transfer or syringe dispensing. The package can be soldered after the adhesive is cured. Reflow soldering Reflow soldering techniques are suitable for all SO packages. Maximum permissible solder temperature is 260 °C, and maximum duration of package immersion in solder is 10 seconds, if cooled to less than 150 °C within 6 seconds. Typical dwell time is 4 seconds at 250 °C. Reflow soldering requires solder paste (a suspension of fine solder particles, flux and binding agent) to be applied to the printed-circuit board by screen printing, stencilling or pressure-syringe dispensing before package placement. A mildly-activated flux will eliminate the need for removal of corrosive residues in most applications. Several techniques exist for reflowing; for example, thermal conduction by heated belt. Dwell times vary between 50 and 300 seconds depending on heating method. Typical reflow temperatures range from 215 to 250 °C. Repairing soldered joints Fix the component by first soldering two diagonallyopposite end leads. Use only a low voltage soldering iron (less than 24 V) applied to the flat part of the lead. Contact time must be limited to 10 seconds at up to 300 °C. When using a dedicated tool, all other leads can be soldered in one operation within 2 to 5 seconds between 270 and 320 °C. Preheating is necessary to dry the paste and evaporate the binding agent. Preheating duration: 45 minutes at 45 °C. 1995 Nov 27 12 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 DEFINITIONS Data sheet status Objective specification This data sheet contains target or goal specifications for product development. Preliminary specification This data sheet contains preliminary data; supplementary data may be published later. Product specification This data sheet contains final product specifications. Limiting values Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information Where application information is given, it is advisory and does not form part of the specification. LIFE SUPPORT APPLICATIONS These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such improper use or sale. 1995 Nov 27 13 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 NOTES 1995 Nov 27 14 Philips Semiconductors Product specification Digital Servo Driver (DSD-2) OQ8844 NOTES 1995 Nov 27 15 Philips Semiconductors – a worldwide company Argentina: IEROD, Av. Juramento 1992 - 14.b, (1428) BUENOS AIRES, Tel. (541)786 7633, Fax. (541)786 9367 Australia: 34 Waterloo Road, NORTH RYDE, NSW 2113, Tel. (02)805 4455, Fax. (02)805 4466 Austria: Triester Str. 64, A-1101 WIEN, P.O. Box 213, Tel. (01)60 101-1236, Fax. (01)60 101-1211 Belgium: Postbus 90050, 5600 PB EINDHOVEN, The Netherlands, Tel. (31)40-2783749, Fax. (31)40-2788399 Brazil: Rua do Rocio 220 - 5th floor, Suite 51, CEP: 04552-903-SÃO PAULO-SP, Brazil. P.O. Box 7383 (01064-970), Tel. (011)821-2333, Fax. (011)829-1849 Canada: PHILIPS SEMICONDUCTORS/COMPONENTS: Tel. (800) 234-7381, Fax. (708) 296-8556 Chile: Av. Santa Maria 0760, SANTIAGO, Tel. (02)773 816, Fax. (02)777 6730 China/Hong Kong: 501 Hong Kong Industrial Technology Centre, 72 Tat Chee Avenue, Kowloon Tong, HONG KONG, Tel. (852)2319 7888, Fax. (852)2319 7700 Colombia: IPRELENSO LTDA, Carrera 21 No. 56-17, 77621 BOGOTA, Tel. (571)249 7624/(571)217 4609, Fax. (571)217 4549 Denmark: Prags Boulevard 80, PB 1919, DK-2300 COPENHAGEN S, Tel. (032)88 2636, Fax. (031)57 1949 Finland: Sinikalliontie 3, FIN-02630 ESPOO, Tel. (358)0-615 800, Fax. (358)0-61580 920 France: 4 Rue du Port-aux-Vins, BP317, 92156 SURESNES Cedex, Tel. (01)4099 6161, Fax. (01)4099 6427 Germany: P.O. Box 10 63 23, 20043 HAMBURG, Tel. (040)3296-0, Fax. (040)3296 213. Greece: No. 15, 25th March Street, GR 17778 TAVROS, Tel. (01)4894 339/4894 911, Fax. (01)4814 240 India: Philips INDIA Ltd, Shivsagar Estate, A Block, Dr. Annie Besant Rd. Worli, Bombay 400 018 Tel. (022)4938 541, Fax. (022)4938 722 Indonesia: Philips House, Jalan H.R. Rasuna Said Kav. 3-4, P.O. Box 4252, JAKARTA 12950, Tel. (021)5201 122, Fax. (021)5205 189 Ireland: Newstead, Clonskeagh, DUBLIN 14, Tel. (01)7640 000, Fax. (01)7640 200 Italy: PHILIPS SEMICONDUCTORS S.r.l., Piazza IV Novembre 3, 20124 MILANO, Tel. (0039)2 6752 2531, Fax. (0039)2 6752 2557 Japan: Philips Bldg 13-37, Kohnan 2 -chome, Minato-ku, TOKYO 108, Tel. (03)3740 5130, Fax. (03)3740 5077 Korea: Philips House, 260-199 Itaewon-dong, Yongsan-ku, SEOUL, Tel. (02)709-1412, Fax. (02)709-1415 Malaysia: No. 76 Jalan Universiti, 46200 PETALING JAYA, SELANGOR, Tel. (03)750 5214, Fax. (03)757 4880 Mexico: 5900 Gateway East, Suite 200, EL PASO, TX 79905, Tel. 9-5(800)234-7381, Fax. (708)296-8556 Netherlands: Postbus 90050, 5600 PB EINDHOVEN, Bldg. VB, Tel. (040)2783749, Fax. (040)2788399 New Zealand: 2 Wagener Place, C.P.O. Box 1041, AUCKLAND, Tel. (09)849-4160, Fax. (09)849-7811 Norway: Box 1, Manglerud 0612, OSLO, Tel. (022)74 8000, Fax. (022)74 8341 Pakistan: Philips Electrical Industries of Pakistan Ltd., Exchange Bldg. ST-2/A, Block 9, KDA Scheme 5, Clifton, KARACHI 75600, Tel. (021)587 4641-49, Fax. (021)577035/5874546 Philippines: PHILIPS SEMICONDUCTORS PHILIPPINES Inc., 106 Valero St. Salcedo Village, P.O. Box 2108 MCC, MAKATI, Metro MANILA, Tel. (63) 2 816 6380, Fax. (63) 2 817 3474 Portugal: PHILIPS PORTUGUESA, S.A., Rua dr. António Loureiro Borges 5, Arquiparque - Miraflores, Apartado 300, 2795 LINDA-A-VELHA, Tel. (01)4163160/4163333, Fax. (01)4163174/4163366 Singapore: Lorong 1, Toa Payoh, SINGAPORE 1231, Tel. (65)350 2000, Fax. (65)251 6500 South Africa: S.A. PHILIPS Pty Ltd., 195-215 Main Road Martindale, 2092 JOHANNESBURG, P.O. Box 7430, Johannesburg 2000, Tel. (011)470-5911, Fax. (011)470-5494 Spain: Balmes 22, 08007 BARCELONA, Tel. (03)301 6312, Fax. (03)301 42 43 Sweden: Kottbygatan 7, Akalla. S-164 85 STOCKHOLM, Tel. (0)8-632 2000, Fax. (0)8-632 2745 Switzerland: Allmendstrasse 140, CH-8027 ZÜRICH, Tel. (01)488 2211, Fax. (01)481 77 30 Taiwan: PHILIPS TAIWAN Ltd., 23-30F, 66, Chung Hsiao West Road, Sec. 1. Taipeh, Taiwan ROC, P.O. Box 22978, TAIPEI 100, Tel. (886) 2 382 4443, Fax. (886) 2 382 4444 Thailand: PHILIPS ELECTRONICS (THAILAND) Ltd., 209/2 Sanpavuth-Bangna Road Prakanong, Bangkok 10260, THAILAND, Tel. (66) 2 745-4090, Fax. (66) 2 398-0793 Turkey: Talatpasa Cad. No. 5, 80640 GÜLTEPE/ISTANBUL, Tel. (0 212)279 27 70, Fax. (0212)282 67 07 Ukraine: Philips UKRAINE, 2A Akademika Koroleva str., Office 165, 252148 KIEV, Tel. 380-44-4760297, Fax. 380-44-4766991 United Kingdom: Philips Semiconductors LTD., 276 Bath Road, Hayes, MIDDLESEX UB3 5BX, Tel. (0181)730-5000, Fax. (0181)754-8421 United States: 811 East Arques Avenue, SUNNYVALE, CA 94088-3409, Tel. (800)234-7381, Fax. (708)296-8556 Uruguay: Coronel Mora 433, MONTEVIDEO, Tel. (02)70-4044, Fax. (02)92 0601 Internet: http://www.semiconductors.philips.com/ps/ For all other countries apply to: Philips Semiconductors, International Marketing and Sales, Building BE-p, P.O. Box 218, 5600 MD EINDHOVEN, The Netherlands, Telex 35000 phtcnl, Fax. +31-40-2724825 SCD45 © Philips Electronics N.V. 1995 All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent- or other industrial or intellectual property rights. Printed in The Netherlands 513061/50/01/pp16 Document order number: Date of release: 1995 Nov 27 9397 750 00471