LTC1044A 12V CMOS Voltage Converter U DESCRIPTIO FEATURES 1.5V to 12V Operating Supply Voltage Range 13V Absolute Maximum Rating 200A Maximum No Load Supply Current at 5V Boost Pin (Pin 1) for Higher Switching Frequency 97% Minimum Open Circuit Voltage Conversion Efficiency 95% Minimum Power Conversion Efficiency IS = 1.5A with 5V Supply When OSC Pin = 0V or V + High Voltage Upgrade to ICL7660/LTC1044 UO APPLICATI Conversion of 10V to 10V Supplies Conversion of 5V to 5V Supplies Precise Voltage Division: VOUT = VIN/2 20ppm Voltage Multiplication: VOUT = nVIN Supply Splitter: VOUT = VS/2 Automotive Applications Battery Systems with 9V Wall Adapters/Chargers To optimize performance in specific applications, a boost function is available to raise the internal oscillator frequency by a factor of 7. Smaller external capacitors can be used in higher frequency operation to save board space. The internal oscillator can also be disabled to save power. The supply current drops to 1.5A at 5V input when the OSC pin is tied to GND or V +. UO S The LTC1044A is a monolithic CMOS switched-capacitor voltage converter. It plugs in for ICL7660/LTC1044 in applications where higher input voltage (up to 12V) is needed. The LTC1044A provides several conversion functions without using inductors. The input voltage can be inverted (VOUT = - VIN), doubled (VOUT = 2VIN), divided (VOUT = VIN/2) or multiplied (VOUT = nVIN). TYPICAL APPLICATI Output Voltage vs Load Current, V + = 10V Generating - 10V from 10V 0 LTC1044A 10F 3 4 CAP+ V+ OSC GND LV CAP- VOUT LTC1044A * TA01 8 TA = 25C C1 = C2 = 10F -1 10V INPUT 7 -2 6 5 -10V OUTPUT 10F OUTPUT VOLTAGE (V) 2 + BOOST + 1 -3 -4 -5 -6 SLOPE = 45 -7 -8 -9 -10 0 10 20 30 40 50 60 70 80 90 100 LOAD CURRENT (mA) LTC1044A * TA02 1 LTC1044A W U U W W W AXI U RATI GS U ABSOLUTE PACKAGE/ORDER I FOR ATIO (Note 1) Supply Voltage ........................................................ 13V Input Voltage on Pins 1, 6 and 7 (Note 2) .............................. - 0.3V < VIN < V + + 0.3V Current into Pin 6 ................................................. 20A Output Short-Circuit Duration V + 6.5V ................................................. Continuous Operating Temperature Range LTC1044AC ............................................ 0C to 70C LTC1044AI ........................................ - 40C to 85C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C ORDER PART NUMBER TOP VIEW BOOST 1 8 V+ CAP+ 2 7 OSC GND 3 6 LV CAP- 4 5 VOUT LTC1044ACN8 LTC1044AIN8 N8 PACKAGE 8-LEAD PLASTIC DIP TJMAX = 110C, JA = 100C/W ORDER PART NUMBER TOP VIEW BOOST 1 CAP+ 8 V+ 2 7 OSC GND 3 6 LV CAP- 4 5 VOUT LTC1044ACS8 LTC1044AIS8 S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SOIC 1044A 1044AI TJMAX = 110C, JA = 130C/W Consult factory for Military grade parts ELECTRICAL CHARACTERISTICS V + = 5V, COSC = 0pF, TA = 25C, See Test Circuit, unless otherwise noted. PARAMETER CONDITIONS IS Supply Current RL = , Pins 1 and 7, No Connection RL = , Pins 1 and 7, No Connection, V + = 3V Minimum Supply Voltage RL = 10k Maximum Supply Voltage RL = 10k 12 12 V Output Resistance IL = 20mA, fOSC = 5kHz V + = 2V, IL = 3mA, fOSC = 1kHz 100 120 310 100 130 325 ROUT MIN LTC1044AC LTC1044AI TYP MAX MIN TYP MAX SYMBOL 60 15 200 1.5 60 15 200 UNITS A A 1.5 V fOSC Oscillator Frequency V + = 5V, (Note 3) V + = 2V PEFF Power Efficiency RL = 5k, fOSC = 5kHz 95 98 95 98 % Voltage Conversion Efficiency RL = 97 99.9 97 99.9 % Oscillator Sink or Source Current VOSC = 0V or V + Pin 1 (BOOST) = 0V Pin 1 (BOOST) = V + The denotes specifications which apply over the full operating temperature range; all other limits and typicals TA = 25C. Note 1: Absolute maximum ratings are those values beyond which the life of a device may be impaired. Note 2: Connecting any input terminal to voltages greater than V + or less than ground may cause destructive latch-up. It is recommended that no 2 5 1 5 1 3 20 kHz kHz 3 20 A A inputs from sources operating from external supplies be applied prior to power-up of the LTC1044A. Note 3: fOSC is tested with COSC = 100pF to minimize the effects of test fixture capacitance loading. The 0pF frequency is correlated to this 100pF test point, and is intended to simulate the capacitance at pin 7 when the device is plugged into a test socket and no external capacitor is used. LTC1044A U W TYPICAL PERFOR A CE CHARACTERISTICS Operating Voltage Range vs Temperature Using the Test Circuit Power Efficiency vs Oscillator Frequency, V + = 10V Power Efficiency vs Oscillator Frequency, V + = 5V 100 14 98 12 100 TA = 25C C1 = C2 100F 98 96 8 6 4 10F 94 1F 92 IL = 1mA 90 88 100F 86 10F IL = 15mA 84 2 0 50 100 25 75 AMBIENT TEMPERATURE (C) 1k 10k OSCILLATOR FREQUENCY (Hz) Output Resistance vs Oscillator Frequency, V + = 5V 400 300 200 C1 = C2 = 1F C1 = C2 = 100F C1 = C2 = 10F 100 C1 = C2 = 100F 1k 10k OSCILLATOR FREQUENCY (Hz) 0 100 100k 1k 10k OSCILLATOR FREQUENCY (Hz) 100k Power Conversion Efficiency vs Load Current, V + = 5V 100 100 90 90 80 70 60 IS 50 50 40 40 30 30 20 20 10 10 0 0 0 10 10 90 TA = 25C C1 = C2 = 10F fOSC = 1kHz PEFF 80 40 30 20 50 LOAD CURRENT (mA) 9 8 70 7 60 6 IS 50 5 40 4 30 3 20 2 10 1 0 0 0 4 3 2 5 LOAD CURRENT (mA) 1 6 7 LTC1044A * TPC06 60 70 LTC1044A * TPC07 300 270 PEFF 240 80 70 210 IS 60 180 50 150 40 120 30 90 20 TA = 25C C1 = C2 = 10F fOSC = 20kHz 10 0 0 20 80 60 40 100 LOAD CURRENT (mA) 120 SUPPLY CURRENT (mA) 70 60 POWER CONVERSION EFFICIENCY (%) TA = 25C C1 = C2 = 10F fOSC = 5kHz SUPPLY CURRENT (mA) POWER CONVERSION EFFICIENCY (%) PEFF 100k Power Conversion Efficiency vs Load Current, V + = 10V 100 80 1k 10k OSCILLATOR FREQUENCY (Hz) LTC1044A * TPC05 LTC1044A * TPC04 90 1F 100 POWER CONVERSION EFFICIENCY (%) OUTPUT RESISTANCE () 100 0 100 1F SUPPLY CURRENT (mA) 200 86 Power Conversion Efficiency vs Load Current, V + = 2V TA = 25C IL = 10mA TA = 25C IL = 10mA C1 = C2 = 1F 88 LTC1044A * TPC03 500 500 300 90 80 100 100k Output Resistance vs Oscillator Frequency, V + = 10V 400 100F IL = 15mA 10F LTC1044A * G02 LTC1044A * TPC01 C1 = C2 = 10F 10F 92 82 80 100 125 94 TA = 25C C1 = C2 IL = 1mA 84 1F 82 0 -55 -25 OUTPUT RESISTANCE () POWER EFFICIENCY (%) POWER EFFICIENCY (%) SUPPLY VOLTAGE (V) 96 10 100F 60 30 0 140 LTC1044A * TPC08 3 LTC1044A U W TYPICAL PERFOR A CE CHARACTERISTICS Output Resistance vs Supply Voltage 2.5 TA = 25C IL = 3mA 5 TA = 25C fOSC = 1kHz 2.0 100 COSC = 0pF 1.0 0.5 0 0 1 2 3 SLOPE = 250 - 0.5 -1.0 1 2 3 4 5 6 7 8 LOAD CURRENT (mA) -5 10 Oscillator Frequency as a Function of COSC, V + = 5V 0 -2 -4 SLOPE = 45 320 V + = 2V, fOSC = 1kHz 280 240 200 160 120 V + = 5V, fOSC = 5kHz 80 V + = 10V, fOSC = 20kHz 0 50 25 0 75 100 -55 -25 AMBIENT TEMPERATURE (C) 10 20 30 40 50 60 70 80 90 100 LOAD CURRENT (mA) Oscillator Frequency as a Function of COSC, V + = 10V 100 PIN 1 = V + PIN 1 = OPEN 100 1000 10000 10 EXTERNAL CAPACITOR (PIN 7 TO GND)(pF) LTC1044A * TPC14 Oscillator Frequency vs Temperature 35 100k TA = 25C COSC = 0pF 10k 1k 0.1k 100 1000 10000 10 EXTERNAL CAPACITOR (PIN 7 TO GND)(pF) 10 1 125 COSC = 0pF OSCILLATOR FREQUENCY (kHz) V + = 10V TA = 25C 100 10 1 PIN 1 = OPEN Oscillator Frequency vs Supply Voltage OSCILLATOR FREQUENCY (Hz) 1k 1k LTC1044A * TPC13 LTC1044A * TPC12 10k PIN 1 = V + 10k 40 -8 100k TA = 25C OSCILLATOR FREQUENCY (Hz) 2 100k C1 = C2 = 10F 360 OUTPUT RESISTANCE () 6 4 10 20 30 40 50 60 70 80 90 100 LOAD CURRENT (mA) LTC1044A * TPC11 400 TA = 25C fOSC = 20kHz 0 0 Output Resistance vs Temperature 10 OUTPUT VOLTAGE (V) 9 LTC1044A * TPC10 Output Voltage vs Load Current, V + = 10V -10 -2 -4 0 SLOPE = 80 0 -1 -3 LTC1044A * TPC09 -6 1 -1.5 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V) 8 2 -2.0 -2.5 10 3 OUTPUT VOLTAGE (V) COSC = 100pF TA = 25C fOSC = 5kHz 4 1.5 OUTPUT VOLTAGE (V) OUTPUT RESISTANCE () Output Voltage vs Load Current, V + = 5V Output Voltage vs Load Current, V + = 2V 1000 OSCILLATOR FREQUENCY (Hz) Using the Test Circuit 0 1 2 3 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V) 30 25 V + = 10V 20 15 10 5 0 -55 -25 V + = 5V 50 100 25 75 0 AMBIENT TEMPERATURE (C) 125 LTC1044A * G16 LTC1044A * TPC15 4 LTC1044A * TPC17 LTC1044A TEST CIRCUIT V + (5V) IS 1 8 2 C1 10F 7 LTC1044A 3 4 IL RL 5 LTC1044A * TC VOUT COSC C2 10F W U U UO APPLICATI EXTERNAL OSCILLATOR 6 + + S I FOR ATIO REQUIV Theory of Operation V1 To understand the theory of operation of the LTC1044A, a review of a basic switched-capacitor building block is helpful. In Figure 1, when the switch is in the left position, capacitor C1 will charge to voltage V1. The total charge on C1 will be q1 = C1V1. The switch then moves to the right, discharging C1 to voltage V2. After this discharge time, the charge on C1 is q2 = C1V2. Note that charge has been transferred from the source, V1, to the output, V2. The amount of charge transferred is: q = q1 - q2 = C1(V1 - V2) If the switch is cycled f times per second, the charge transfer per unit time (i.e., current) is: I = f x q = f x C1(V1 - V2) V1 V2 f RL C1 C2 LTC1044A * F01 Figure 1. Switched-Capacitor Building Block Rewriting in terms of voltage and impedance equivalence, I = V1 - V2 = V1 - V2 1/(f x C1) REQUIV A new variable, REQUIV, has been defined such that REQUIV = 1/(f x C1). Thus, the equivalent circuit for the switchedcapacitor network is as shown in Figure 2. V2 C2 REQUIV = 1 f x C1 RL LTC1044A * F02 Figure 2. Switched-Capacitor Equivalent Circuit Examination of Figure 3 shows that the LTC1044A has the same switching action as the basic switched-capacitor building block. With the addition of finite switch-on resistance and output voltage ripple, the simple theory although not exact, provides an intuitive feel for how the device works. For example, if you examine power conversion efficiency as a function of frequency (see typical curve), this simple theory will explain how the LTC1044A behaves. The loss, and hence the efficiency, is set by the output impedance. As frequency is decreased, the output impedance will eventually be dominated by the 1/(f x C1) term, and power efficiency will drop. The typical curves for Power Efficiency vs Frequency show this effect for various capacitor values. Note also that power efficiency decreases as frequency goes up. This is caused by internal switching losses which occur due to some finite charge being lost on each switching cycle. This charge loss per unit cycle, when multiplied by the switching frequency, becomes a current loss. At high frequency this loss becomes significant and the power efficiency starts to decrease. 5 LTC1044A U W U UO APPLICATI S I FOR ATIO V+ (8) SW1 SW2 C+ (2) BOOST 7X (1) + C1 /2 OSC OSC (7) C- (4) VOUT (5) + CLOSED WHEN V + > 3V LV (6) C2 LTC1044A * F03 GND (3) Figure 3. LTC1044A Switched-Capacitor Voltage Converter Block Diagram LV (Pin 6) The internal logic of the LTC1044A runs between V + and LV (pin 6). For V + greater than or equal to 3V, an internal switch shorts LV to GND (pin 3). For V + less than 3V, the LV pin should be tied to GND. For V + greater than or equal to 3V, the LV pin can be tied to GND or left floating. OSC (Pin 7) and Boost (Pin 1) The switching frequency can be raised, lowered, or driven from an external source. Figure 4 shows a functional diagram of the oscillator circuit. By connecting the boost pin (pin 1) to V +, the charge and discharge current is increased and hence, the frequency is increased by approximately 7 times. Increasing the V+ 6I frequency will decrease output impedance and ripple for higher load currents. Loading pin 7 with more capacitance will lower the frequency. Using the boost (pin 1) in conjunction with external capacitance on pin 7 allows user selection of the frequency over a wide range. Driving the LTC1044A from an external frequency source can be easily achieved by driving pin 7 and leaving the boost pin open as shown in Figure 5. The output current from pin 7 is small (typically 0.5A) so a logic gate is capable of driving this current. The choice of using a CMOS logic gate is best because it can operate over a wide supply voltage range (3V to 15V) and has enough voltage swing to drive the internal Schmitt trigger shown in Figure 4. For 5V applications, a TTL logic gate can be used by simply adding an external pull-up resistor (see Figure 5). I V+ BOOST (1) NC 1 8 2 C1 ~14pF 6I LV (6) SCHMITT TRIGGER 4 OSC INPUT 6 5 -(V +) C2 LTC1044A * F05 I LTC1044A * F04 Figure 5. External Clocking Figure 4. Oscillator 6 OSC (7) 3 7 LTC1044A + + 100k REQUIRED FOR TTL LOGIC LTC1044A W U U UO APPLICATI S I FOR ATIO Capacitor Selection External capacitors C1 and C2 are not critical. Matching is not required, nor do they have to be high quality or tight tolerance. Aluminum or tantalum electrolytics are excellent choices with cost and size being the only consideration. Negative Voltage Converter Figure 6 shows a typical connection which will provide a negative supply from an available positive supply. This circuit operates over full temperature and power supply ranges without the need of any external diodes. The LV pin (pin 6) is shown grounded, but for V + 3V it may be "floated", since LV is internally switched to ground (pin 3) for V + 3V. The output voltage (pin 5) characteristics of the circuit are those of a nearly ideal voltage source in series with an 80 resistor. The 80 output impedance is composed of two terms: 1. The equivalent switched-capacitor resistance (see Theory of Operation). 2. A term related to the on-resistance of the MOS switches. At an oscillator frequency of 10kHz and C1 = 10F, the first term is: REQUIV = = 1 (fOSC/2) x C1 The exact expression for output resistance is extremely complex, but the dominant effect of the capacitor is clearly shown on the typical curves of Output Resistance and Power Efficiency vs Frequency. For C1 = C2 = 10F, the output impedance goes from 60 at fOSC = 10kHz to 200 at fOSC = 1kHz. As the 1/(f x C) term becomes large compared to the switch-on resistance term, the output resistance is determined by 1/(f x C) only. Voltage Doubling Figure 7 shows a two-diode capacitive voltage doubler. With a 5V input, the output is 9.93V with no load and 9.13V with a 10mA load. With a 10V input, the output is 19.93V with no load and 19.28V with a 10mA load. VIN (1.5V TO 12V) 1 8 2 3 7 LTC1044A Vd 1N5817 6 4 REQUIRED FOR V + < 3V 5 Vd 1N5817 + + VOUT = 2(VIN - 1) + 10F 10F LTC1044A * F07 Figure 7. Voltage Doubler Ultra-Precision Voltage Divider An ultra-precision voltage divider is shown in Figure 8. To achieve the 0.0002% accuracy indicated, the load current should be kept below 100nA. However, with a slight loss in accuracy the load current can be increased. 1 = 20 5 x 103 x 10 x 10 -6 Notice that the above equation for REQUIV is not a capacitive reactance equation (XC = 1/C) and does not contain a 2 term. + + C1 10F 1 8 2 7 3 LTC1044A 4 V + (3V TO 24V) 6 5 LTC1044A * F08 V +/2 0.002% 1 8 2 10F 3 7 LTC1044A 4 6 REQUIRED FOR V + < 3V 5 LTC1044A * F06 VOUT = - V + + + V + (1.5V TO 12V) TMIN TA TMAX IL 100nA + C2 10F REQUIRED FOR V + < 6V Figure 8. Ultra-Precision Voltage Divider 10F TMIN TA TMAX Figure 6. Negative Voltage Converter 7 LTC1044A W U U UO APPLICATI S I FOR ATIO Battery Splitter (output common). If the input voltage between pin 8 and pin 5 is less than 6V, pin 6 should also be connected to pin 3 as shown by the dashed line. A common need in many systems is to obtain (+) and (-) supplies from a single battery or single power supply system. Where current requirements are small, the circuit shown in Figure 9 is a simple solution. It provides symmetrical output voltages, both equal to one half input voltage. The output voltages are both referenced to pin 3 + VB 12V + C1 1 8 2 7 3 10F LTC1044A 4 6 5 Paralleling for Lower Output Resistance Additional flexibility of the LTC1044A is shown in Figures 10 and 11. Figure 10 shows two LTC1044As connected in parallel to provide a lower effective output resistance. If, however, the output resistance is dominated by 1/(f x C1), increasing the capacitor size (C1) or increasing the frequency will be of more benefit than the paralleling circuit shown. +VB/2 (6V) REQUIRED FOR V B < 6V +VB/2 (-6V) Figure 11 makes use of "stacking" two LTC1044As to provide even higher voltages. A negative voltage doubler or tripler can be achieved, depending upon how pin 8 of the second LTC1044A is connected, as shown schematically by the switch. The available output current will be dictated/ decreased by the product of the individual power conversion efficiencies and the voltage step-up ratio. LTC1044A * F09 C2 10F + OUTPUT COMMON Figure 9. Battery Splitter V+ + C1 1 8 1 2 7 2 3 10F LTC1044A 4 + C1 6 3 10F 5 8 7 LTC1044A 6 4 5 V OUT = -(V + ) 1/4 CD4077 + * C2 20F LTC1044A * F10 *THE EXCLUSIVE NOR GATE SYNCHRONIZES BOTH LTC1044As TO MINIMIZE RIPPLE Figure 10. Paralleling for Lower Output Resistance + 10F 1 8 2 7 3 4 LTC1044A FOR V OUT = -3V + 10F + 6 5 1 10F 8 2 3 - (V + ) 7 LTC1044A 4 6 5 LTC1044A * F11 + Figure 11. Stacking for Higher Voltage 8 FOR V OUT = -2V + V OUT + V+ 10F LTC1044A U TYPICAL APPLICATIO S Low Output Impedance Voltage Converter 200k 8.2k VIN* 7 + 6 LM10 39k 2 VOUT ADJ 50k - 8 4 50k 200k 7 8 + 1 6 OUTPUT 5 100F + 3 10F LTC1044A LTC1044 * F12 0.1F 39k 1 2 3 4 10F *VIN -VOUT + 0.5V LOAD REGULATION 0.02%, 0mA TO 15mA + Single 5V Strain Gauge Bridge Signal Conditioner + 100F 1 8 2 7 LTC1044A 3 6 5 -5V 4 220 5V 100F + 4 8 0.33F 3 + 1 1.2V REFERENCE TO A/D CONVERTER FOR RATIOMETRIC OPERATION (1mA MAX) D 2 100k 10k LT1004 ZERO 1.2V TRIM 301k* 350 PRESSURE TRANSDUCER 5 0V 0.047F 46k* LT1413 A E 2k GAIN TRIM - OUTPUT 0V TO 3.5V 0psi to 350psi 100* + 7 39k *1% FILM RESISTOR PRESSURE TRANSDUCER BLH/DHF-350 (CIRCLED LETTER IS PIN NUMBER) -1.2V 6 C - 0.1F LTC1044A * F13 9 LTC1044A U TYPICAL APPLICATIO S Regulated Output 3V to 5V Converter 3V 1N914 200 1 8 2 7 LTC1044A 3 + 4 10F 5V OUTPUT + 100F 6 5 1M 4.8M 7 8 - 1k 1 330k REF AMP + EVEREADY EXP-30 LM10 2 - 1k 6 OP AMP 3 + 4 1N914 100k 150k LTC1044A * F14 Low Dropout 5V Regulator 2N2219 VOUT = 5V 1N914 200 + 10F 1 8 2 7 3 LTC1044A 4 12V + 10F 6 100 120k 5 100k SHORT-CIRCUIT PROTECTION 1M 6V 4 EVEREADY E-91 CELLS 8 5 FEEDBACK AMP V+ 2 LOAD + - 7 LT1013 3 + - V- 4 LT1004 1.2V 0.01 1.2k 1 1N914 6 30k 50k OUTPUT ADJUST LTC1044A * F15 10 VDROPOUT AT 1mA = 1mV VDROPOUT AT 10mA = 15mV VDROPOUT AT 100mA = 95mV LTC1044A U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead Plastic DIP 0.400 (10.160) MAX 8 7 6 5 0.250 0.010 (6.350 0.254) 1 0.300 - 0.320 (7.620 - 8.128) 0.009 - 0.015 (0.229 - 0.381) ( +0.025 0.325 -0.015 +0.635 8.255 -0.381 ) 2 4 3 0.130 0.005 (3.302 0.127) 0.045 - 0.065 (1.143 - 1.651) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.045 0.015 (1.143 0.381) 0.018 0.003 (0.457 0.076) 0.100 0.010 (2.540 0.254) 0.020 (0.508) MIN N8 0392 S8 Package 8-Lead Plastic SOIC 0.189 - 0.197 (4.801 - 5.004) 8 7 6 5 0.150 - 0.157 (3.810 - 3.988) 0.228 - 0.244 (5.791 - 6.197) 1 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 2 3 4 0.053 - 0.069 (1.346 - 1.752) 0.004 - 0.010 (0.101 - 0.254) 0- 8 TYP 0.016 - 0.050 0.406 - 1.270 0.014 - 0.019 (0.355 - 0.483) 0.050 (1.270) BSC Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. SO8 0392 11 LTC1044A U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation One Oxford Valley 2300 E. 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Immeuble "Le Quartz" 58 Chemin de la Justice 92290 Chatenay Malabry France Phone: 33-1-41079555 FAX: 33-1-46314613 KOREA Linear Technology Korea Branch Namsong Building, #505 Itaewon-Dong 260-199 Yongsan-Ku, Seoul Korea Phone: 82-2-792-1617 FAX: 82-2-792-1619 TAIWAN Linear Technology Corporation Rm. 801, No. 46, Sec. 2 Chung Shan N. Rd. Taipei, Taiwan, R.O.C. Phone: 886-2-521-7575 FAX: 886-2-562-2285 GERMANY Linear Technology GMBH Untere Hauptstr. 9 D-85386 Eching Germany Phone: 49-89-3197410 FAX: 49-89-3194821 SINGAPORE Linear Technology Pte. Ltd. 101 Boon Keng Road #02-15 Kallang Ind. Estates Singapore 1233 Phone: 65-293-5322 FAX: 65-292-0398 UNITED KINGDOM Linear Technology (UK) Ltd. The Coliseum, Riverside Way Camberley, Surrey GU15 3YL United Kingdom Phone: 44-276-677676 FAX: 44-276-64851 JAPAN Linear Technology KK 5F YZ Bldg. 4-4-12 Iidabashi, Chiyoda-Ku Tokyo, 102 Japan Phone: 81-3-3237-7891 FAX: 81-3-3237-8010 World Headquarters Linear Technology Corporation 1630 McCarthy Blvd. Milpitas, CA 95035-7487 Phone: (408) 432-1900 FAX: (408) 434-0507 08/16/93 12 Linear Technology Corporation LT/GP 1293 10K REV 0 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977 LINEAR TECHNOLOGY CORPORATION 1993