L6242 VOICE COIL MOTOR DRIVER ADVANCE DATA OUTPUT CURRENT UP TO 1A OPERATES AT LOW VOLTAGES WITH LOW COIL RESISTANCE OF THE MOTOR LARGE COMMON MODE AND DIFFERENTIAL MODE RANGE LOW INPUT OFFSET VOLTAGE THERMAL SHUT-DOWN ENABLE FUNCTION INTERNAL CLAMP DIODES SO20 DESCRIPTION The L6242 is a monolithic integrated circuit in SO-20 package intended for use as a dual power operational amplifier. It is particularly indicated for driving inductive loads as linear motor, and finds application in Hard Disc, Compact-Disc, etc. The two power operational amplifiers are controlled by a common enable input. ORDERING NUMBER: L6242 The high gain and output power capability provide superior performance whatever a power booster is required. PIN CONNECTION AND BLOCK DIAGRAM November 1991 1/5 This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice. T is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without L6242 ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit 28 V Input Voltage VS V Differential Input Voltage ±VS V 1 A VS Supply Voltage Vi Vi IO DC Output Current IP Peak Output Current (non repetitive) Ptot Tstg, TJ Maximum Power Dissipation at Tamb = 85°C TCASE = 75°C Storage and Junction Temperature Range 1.5 A 1 5 W W -40 to 150 °C ELECTRICAL CHARACTERISTICS (VS = 12V, TJ = 25°C unless otherwise specified) Symbol Parameter VS Supply Voltage IS Quiescent Drain Current Ib Input Bias Current Min. Typ. 4 VO = VS/2 10 0.2 VOS Input Offset Voltage IOS Input Offset Current 10 Sr Slew Rate 1.5 Max. Unit 28 V 15 mA 1 µA 15 mV 50 nA V/µs Ri Input Resistance GV Open Loop Voltage Gain f = 100Hz 70 80 dB CMR Common Mode Rejection f = 100Hz 66 84 dB SVR Supply Voltage Rejection f = 100Hz R g = 10KΩ Vr = 0.5V 54 dB Vdrop High Drop Voltage I = 100mA I = 500mA 0.7 1 1.5 V V I = 100mA I = 500mA 0.3 0.6 1 V V 50 KΩ Vdrop Low Drop Voltage 500 Tsd Thermal Shutdown Junction Temperature Rp Internal Pull-up Resistor of the Enable Input Ve Enable Low Voltage TJ = 130°C Ieq Quiescent Drain Current En = L Td Enable Delay Iol Output Leakage Current APPLICATION INFORMATIONS Figure 1 shows the L6242 configurated as a transconductance amplifier, in order to drive linear motors as Voice Coil (VCM). The L6242 provides the power section of the Transconductance Amplifier. The two OP AMP are configurated one as inverting and the other as noninverting amplifier, with the same gain. Working in push-pull, they can be configurated as a bridge. The motor current can be controlled by means of the sense resistor (typical 1Ω) in series with the motor. The current sense amplifier provides the feedback signal, which is summed to the driving signal at the node which is the inverting input of the Error Am2/5 Test Condition KΩ °C 145 -0.3 2 1.2 V 5 mA 50 10 µs µA plifier. R1 closes the control loop. R2 converts the input voltage signal, into a current signal. The snubber network provides the system stability, always required by the application. The network is directly connected to the output pins of the IC, OUT1 and OUT2, and in parallel with the load. R4 and C2 could be of different values, depending on the p.c.b. configuration and on the motor characteristics. The DC transfer function may be expressed as: gm = Iout/Vin = k • (R1/R2) where k = 1/(Rsense • Ad) and Ad = gain of the current sense amplifier. L6242 Figure 1: Voice Coil Motor Control Circuit OPTIMIZING LAYOUT Optimizing a PC board layout involves to observe the following rules which in general can avoid application problems associated with ground loops and anomalous recirculation currents. The electrolytic capacitor for the power supply must be kept as close to the IC as possible. It is important that power grounds are close to each other on a wide enough. Copper side also, it is important to separate on the board the logic ground and the power ground in such a way that the ground traces for the logic signals and references do not cross the ground traces for the power signals. Logic ground and power ground must meet at one point on the board (startpoint grounding) far enough away from where the power ground traces terminate to ground (sense resistors and recirculation diodes). This is to avoid anomalous interface with the logic signals. It is generally a good idea to connect a non inductive capacitor (typically 100nF) between the pins VS and GND. In other cases it may be necessary to also place a by-pass capacitor between the pins Vref and GND. 3/5 L6242 SO20 PACKAGE MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. TYP. 2.65 0.1 MAX. 0.104 0.3 a2 0.004 0.012 2.45 0.096 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.013 C 0.5 0.020 c1 45 (typ.) D 12.6 13.0 0.496 0.512 E 10 10.65 0.394 0.419 e 1.27 0.050 e3 11.43 0.450 F 7.4 7.6 0.291 0.299 L 0.5 1.27 0.020 0.050 M S 4/5 MIN. 0.75 0.030 8 (max.) L6242 Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. 1994 SGS-THOMSON Microelectronics - All Rights Reserved SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco - The Netherlands - Singapore Spain - Sweden - Switzerland - Taiwan - Thaliand - United Kingdom - U.S.A. 5/5