LT1301CN8

LT1301 Micropower High Efficiency 5V/12V Step-Up DC/DC Converter for Flash Memory FEATURES s s s s s s s s s s s DESCRIPTION The LT1301 is a micropower step-up DC/DC converter that utilizes Burst Mode™ operation. The device can deliver 5V or 12V from a two-cell battery input. It features programmable 5V or 12V output via a logic-controlled input, noload quiescent current of 120µA and a shutdown pin which reduces supply current to 10µA. The on-chip power switch has a low 170mV saturation voltage at a switch current of 1A, a four-fold reduction over prior designs. A 155kHz internal oscillator allows the use of extremely small surface mount inductors and capacitors. Operation is guaranteed at 1.8V input. This allows more energy to be extracted from the battery, increasing operating life. The ILIM pin can be used for soft start or to program peak switch current with a single resistor allowing the use of even smaller inductors in lighter load applications. The LT1301 is available in an 8-lead SOIC package, minimizing board space requirements. For a selectable 3.3V/5V step-up converter, please see the LT1300. For higher output power, see the LT1302. Burst Mode is a trademark of Linear Technology Corporation. 12V at 120mA from 5V or 3.3V Supply Supply Voltage as Low as 1.8V Better High Current Efficiency Than CMOS Up to 89% Efficiency 120µA Quiescent Current Shutdown to 10µA Programmable 5V or 12V Output Low VCESAT Switch: 170mV at 1A Typical ILIM Pin Programs Peak Switch Current Uses Inexpensive Surface Mount Inductors 8-Lead DIP or SOIC Package APPLICATIONS s s s s s s Flash Memory VPP Generator Palmtop Computers Portable Instruments Bar-Code Scanners Personal Digital Assistants PCMCIA Cards TYPICAL APPLICATIONS N 5V OR 3.3V VIN SELECT L1 33µH D1 Output Voltage 12V OUTPUT 12V VOUT 2V/DIV SW SENSE 47µF SHUTDOWN SHDN PGND + C2 ILIM GND N/C 33µF 20V 0.1µF* SHUTDOWN 10V/DIV 1ms/DIV LT1301 F1 EFFICIENCY (%) + C1 LT1301 *REQUIRED FOR 5V OUTPUT L1 = COILCRAFT DO3316-333 OR SUMIDA CD73-330KC D1 = 1N5817 OR MOTOROLA MBRS130LT3 C1 = AVX TPSD476M016R0100 OR SANYO OS-CON 165A47M C2 = AVX TPSD336M020R0100 OR SANYO OS-CON 205A33M VIN = 5V, VOUT = 12V LOAD = 100Ω LT1301 TAO1 Figure 1. 3.3V/5V to 12V Step-Up Converter U U U Efficiency 90 88 86 84 82 80 78 76 74 72 0 1 10 100 LOAD CURRENT (mA) 300 LT1301 TA2 VIN = 5V VIN = 3.3V LT1300 F2 1 LT1301 ABSOLUTE MAXIMUM RATINGS VIN Voltage .............................................................. 10V SW1 Voltage ............................................................ 20V Sense Voltage .......................................................... 20V Shutdown Voltage ................................................... 10V Select Voltage .......................................................... 10V ILIM Voltage ............................................................ 0.5V Maximum Power Dissipation ............................. 500mW Operating Temperature Range LT1301C ................................................... 0°C to 70°C LT1301I .................................................. 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C PACKAGE/ORDER INFORMATION TOP VIEW GND 1 SEL 2 SHDN 3 SENSE 4 N8 PACKAGE 8-LEAD PLASTIC DIP 8 7 6 5 PGND SW VIN ILIM ORDER PART NUMBER LT1301CN8 LT1301CS8 LT1301IS8 S8 PART MARKING 1301 1301I S8 PACKAGE 8-LEAD PLASTIC SOIC TJMAX = 100°C, θJA = 150°C/ W ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER IQ Quiescent Current VIN VOUT Input Voltage Range TA = 25°C, VIN = 2V unless otherwise noted. MIN q q q CONDITIONS VSHDN = 0.5V, VSEL = 5V, VSENSE = 5.5V VSHDN = 1.8V TYP 120 7 MAX 200 15 Output Sense Voltage Output Referred Comparator Hysteresis Oscillator Frequency Oscillator TC Maximum Duty Cycle Switch On-Time Output Line Regulation Switch Saturation Voltage Switch Leakage Current Peak Switch Current (Internal Trip Point) Shutdown Pin High Shutdown Pin Low Select Pin High Select Pin Low Shutdown Pin Bias Current VSEL = 5V VSEL = 0V VSEL = 5V (Note 1) VSEL = 0V (Note 1) Current Limit not Asserted. q q q q 1.8 2.0 11.52 4.75 120 75 DC tON VCESAT Current Limit not Asserted. 1.8V < VIN < 6V ISW = 700mA VSW = 5V, Switch Off ILIM Floating (See Typical Application) ILIM Grounded q q q 0.75 q q q 12.00 5.00 50 22 155 0.2 86 5.6 0.06 130 0.1 1.0 0.4 12.48 5.25 100 50 185 95 0.15 200 10 1.25 VSHDNH VSHDNL VSELH VSELL ISHDN 1.8 0.5 1.5 8 3 0.1 1 0.8 20 1 3 ISEL Select Pin Bias Current VSHDN = 5V VSHDN = 2V VSHDN = 0V 0V < VSEL < 5V q q q q UNITS µA µA V V V V mV mV kHz %/ °C % µs %/V mV µA A A V V V V µA µA µA µA The q denotes specifications which apply over the 0°C to 70°C temperature range. Note 1: Hysteresis specified is DC. Output ripple may be higher if output capacitance is insufficient or capacitor ESR is excessive. See operation section. 2 U W U U WW W LT1301 TYPICAL PERFORMANCE CHARACTERISTICS 5V Output Efficiency 90 88 86 84 VIN = 3.3V 60 50 40 30 20 10 0 SHUTDOWN CURRENT (µA) ISHDN + IVIN + ISENSE (µA) EFFICIENCY (%) VIN = 2.5V 82 80 78 76 74 72 70 1 10 100 LOAD CURRENT (mA) 1000 LT1301 G1 Saturation Voltage vs Switch Current 250 225 SATURATION VOLTAGE (mV) TA = 25°C 200 175 150 125 100 75 50 25 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 SWITCH CURRENT (A) 1 INPUT CURRENT (µA) Load Transient Response of Figure 1 Circuit 12V VOUT 100mV/DIV AC COUPLED VOUT 2V/DIV 5V ILOAD 120mA 0mA VIN = 3.3V 200µs/DIV LT1301 G7 UW LT1301 G4 Total Quiescent Current in Shutdown 80 TA = 25°C 70 Shutdown Pin Bias Current 20 18 16 14 12 10 8 6 4 2 0 TA = 25°C 0 1 2 4 5 6 3 INPUT VOLTAGE (V) 7 8 0 1 6 4 3 2 5 SHUTDOWN VOLTAGE (V) 7 8 LT1301 G2 LT1300 G3 No-Load Input Current 500 450 400 350 300 250 200 150 100 2 VOUT = 5V VOUT = 12V ILOAD VOUT 100mV/DIV AC COUPLED 120mA 0mA Load Transient Response of Figure 1 Circuit 200µs/DIV VIN = 5V LT1301 G6 3 4 5 INPUT VOLTAGE (V) 6 7 LT1301 G5 Select Pin Transient Response 12V VOUT 2V/DIV Select Pin Transient Response 5V VSELECT 10V/DIV 5ms/DIV COUT = 100µF, VIN = 5V 100Ω LOAD 5ms/DIV LT1301 G8 LT1301 G9 VSELECT 10V/DIV COUT = 100µF, VIN = 3.3V 100Ω LOAD 3 LT1301 PIN FUNCTIONS GND (Pin 1): Signal Ground. Tie to PGND under the package. Sel (Pin 2): Output Select. When tied to VIN converter regulates at 12V. When grounded or floating converter regulates at 5V. May be driven under logic control. SHDN (Pin 3): Shutdown. Pull high to shut down the LT1301. Ground for normal operation. Sense (Pin 4): “Output” Pin. Goes to internal resistive divider. If operating at 5V output, a 0.1µF ceramic capacitor is required from Sense to Ground. ILIM (Pin 5): Float for 1A switch current limit. Tie to ground for approximately 400mA. A resistor between ILIM and ground sets peak current to some intermediate value . VIN (Pin 6): Supply Pin. Must be bypassed with a large value electrolytic to ground. Keep bypass within 0.2" of the device. SW (Pin 7): Switch Pin. Connect inductor and diode here. Keep layout short and direct to minimize radio frequency interference. PGND (Pin 8): Power Ground. Tie to signal ground (pin 1) under the package. Bypass capacitor from VIN should be tied directly to PGND within 0.2" of the device. BLOCK DIAGRAM VIN + C1 1.25V REFERENCE 97.5k 4 W U U U L1 D1 VOUT + C2 SENSE 4 2 VIN 7 SW 18mV A2 CURRENT COMPARATOR 500k + – R2 730Ω R1 3Ω A1 COMPARATOR OFF + ENABLE OSCILLATOR 155kHZ A3 DRIVER – BIAS Q3 8.5k Q2 1× Q1 160× 69.2k GND 1 2 SELECT SHUTDOWN 3 5 ILIM PGND 8 LT1301 F2 Figure 2. LT1301 TEST CIRCUITS 2V VIN SEL 100µF LT1301 IL SW 5V 100Ω fOUT SENSE GND SHDN PGND Oscillator Test Circuit LT1301 TC OPERATION Operation of the LT1301 is best understood by referring to the Block Diagram in Figure 2. When A1’s negative input, related to the Sense pin voltage by the appropriate resistor-divider ratio is higher that the 1.25V reference voltage, A1’s output is low. A2, A3 and the oscillator are turned off, drawing no current. Only the reference and A1 consume current, typically 120µA. When A1’s negative input drops below 1.25V, overcoming A1’s 6mV hysteresis, A1’s output goes high enabling the oscillator, current comparator A2, and driver A3. Quiescent current increases to 2mA as the device prepares for high current switching. Q1 then turns on in controlled saturation for (nominally) 5.3µs or until comparator A2 trips, whichever comes first. After a fixed off-time of (nominally) 1.2µs, Q1 turns on again. The LT1301’s switching causes current to alternately build up in L1 and dump into output capacitor C2 via D1, increasing the output voltage. When the output is high enough to cause A1’s output to go to low, switching action ceases. C2 is left to supply current to the load until VOUT decreases enough to force A1’s output high, and the entire cycle repeats. Figure 4 details relevant waveforms. A1’s cycling causes low-to-mid-frequency ripple voltage on the output. Ripple can be reduced by making the output capacitor large. The 33µF unit specified results in ripple of 100mV to 200mV on the 12V output. A 100µF capacitor will decrease ripple to 50mV. If operating at 5V ouput a 0.1µF ceramic capacitor is required at the Sense pin in addition to the electrolytic. If switch current reaches 1A, causing A2 to trip, switch ontime is reduced and off-time increases slightly. This allows continuous mode operation during bursts. A2 monitors the voltage across 3Ω resistor R1 which is directly related to the switch current. Q2’s collector current is set by the emitter-area ratio to 0.6% of Q1’s collector current. When R1’s voltage drop exceeds 18mV, corresponding to 1A switch current, A2’s output goes high, truncating the ontime portion of the oscillator cycle and increasing off-time to about 2µs as shown in Figure 3, trace A. This programmed peak current can be reduced by tying the ILIM pin to ground, causing 15µA to flow through R2 into Q3’s collector. Q3’s current causes a 10.4mV drop in R2 so that only an additional 7.6mV is required across R1 to turn off the switch. This corresponds to a 400mA switch current as shown in Figure 3, trace B. The reduced peak switch current reduces I2R loses in Q1, L1, C1 and D1. Efficiency can be increased by doing this provided that the accompanying reduction in full load current is acceptable. Lower peak currents also extend alkaline battery life due to the alkaline cell’s high internal impedance. TRACE A 500mA/DIV ILIM PIN OPEN TRACE B 500mA/DIV ILIM PIN GROUNDED 20µs/DIV U Figure 3. Switch Pin Current With ILIM Floating or Grounded 5 LT1301 APPLICATIONS INFORMATION VOUT 100mV/DIV AC COUPLED VSW 10V/DIV VOUT 5V/DIV IIN 500mA/DIV VSHDN 10V/DIV 20µs/DIV VIN = 5V, VOUT = 12V, L = 33µH COUT = 33µF, ILOAD = 90mA LT1300 F4 IL 500mA/DIV Figure 4. Burst Mode Operation in Action Output Voltage Selection The LT1301 can be selected to 5V or 12V under logic control or fixed at either by tying Select to ground or VIN respectively. It is permissible to tie Select to a voltage higher than VIN as long as it does not exceed 10V. Efficiency in 5V mode will be slightly less that in 12V mode due to the fact that the diode drop is a greater percentage of 5V than 12V. Since the bipolar switch in the LT1301 gets its base drive from VIN, no reduction in switch efficiency occurs when in 5V mode. When VIN exceeds the programmed output voltage the output will follow the input. This is characteristic of the simple step-up or “boost” converter topology. A circuit example that provides a regulated output with an input voltage above or below the output (known as a buck-boost or SEPIC) is shown in the Typical Applications section. Shutdown The converter can be turned off by pulling SHDN (pin 3) high. Quiescent current drops to 10µA in this condition. Bias current of 8µA to 10µA flows into the pin (at 5V input). It is recommended that SHDN not be left floating. Tie the pin to ground if the feature is not used. SHDN can be driven high even if VIN is floating. ILIM Function The LT1301’s current limit (ILIM) pin can be used for soft start. Upon start-up, the LT1301 will draw maximum current from the supply (about 1A) from the supply to charge the output capacitor. Figure 5 shows VOUT and IIN waveforms as the device is turned on. The high current flow can create IR drops along supply and ground lines or cause the input supply to drop out momentarily. By 6 U W U U 200µs/DIV VIN = 5V, VOUT = 12V LT1300 F5 Figure 5. Start-Up Response L1 33µH D1 1N5817 VIN 3.3V OR 5V VIN SELECT SW SENSE LT1301 12V + 47µF SHUTDOWN SHDN GND + C2 33µF ILIM PGND R1 1M C3 0.1µF LT1301 F6 Figure 6. VOUT 5VDIV IIN 500mA/DIV VSHDN 10V/DIV 200µs/DIV VIN = 5V, VOUT = 12V LT1300 F5 Figure 7. Startup Response Soft-Start Circuitry Added adding R1 and C3 as shown in Figure 6, the switch current in the LT1301 is initially limited to 400mA until the 15µA flowing out of the ILIM pin charges up C3. Input current is held to under 500mA while the output voltage ramps up to 12V as shown in Figure 7. R1 provides a discharge path for the capacitor without appreciably decreasing peak switch current. When using the ILIM pin softstart mode a minimum load of a few hundred microamperes is recommended to prevent C3 from discharging, as no current flows out of ILIM when the LT1301 is not LT1301 APPLICATIONS INFORMATION Table 1. Recommended Inductors L (µH) DCR (Ω) VIN(V) 33 0.088 3.3 5 DO1608-223 Coilcraft 22 .31 3.3 3.3 5 5 DO1608-103 Coilcraft 10 .11 2 CTX20-1 Coiltronics 20 .175 3.3 5 GA10-332 Gowanda 33 .077 3.3 5 LQH3G220K04M00 Murata-Erie 22 0.7 3.3 5 CD73-330KC Sumida 33 0.131 3.3 5 CDRH62-330MC Sumida 33 0.48 3.3 PART NUMBER DO3316-333 VENDOR Coilcraft 5 ILIM PIN Open Open Open Ground 10k Ground Open Open Open Open Open Ground Ground Open Open Open Ground Open Ground EFFICIENCY (%) 30mA 60mA 120mA 84 84 85 89 89 90 82 82 — 85 — — 86 87 — 88 — — 78 — — 84 84 — 88 88 89 86 86 87 89 89 90 81 — — 85 — — 84 85 86 88 88 89 80 80 81 85 — — 84 84 85 83 — — COMPONENT HEIGHT (mm) 5.5 3.5 PHONE NUMBER (708) 639–6400 switching. Zero load current causes the LT1301 to switch so infrequently that C3 can completely discharge reducing subsequent peak switch current to 400mA. If a load is suddenly applied, output voltage will sag until C3 can be recharged and peak switch current returns to 1A. If the full capacity of the LT1301 is not required peak current can be reduced by changing the value of R3 as shown in Figure 8. With R3 = 0 switch current is limited to approximately 400mA. Smaller, less expensive inductors with lower saturation ratings can then be used. Inductor Selection For full output power, the inductor should have a saturation current rating of 1.25A for worst-case current limit, although it is acceptable to bias an inductor 20% or more into saturation. Smaller inductors can be used in conjunction with the ILIM pin. Efficiency is significantly affected by inductor DCR. For best efficiency limit the DCR to 0.03Ω or less. Toroidal types are preferred in some cases due to their inherent flux containment and EMI/RFI superiority. Recommended inductors are listed in Table 1. SWITCH CURRENT (mA) U W U U 3.5 4.2 Through-Hole 2.0 3.5 3.0 (407) 241-7876 (716) 532-2234 (404) 436-1300 (708) 956-0666 Table 2. Recommended Capacitors VENDOR AVX Sanyo Panasonic SERIES TPS OS-CON HFQ TYPE Surface Mount Through-Hole Through-Hole PHONE# (803)448–9411 (619) 661–6835 (201) 348-5200 1100 1000 900 800 700 600 500 400 1.6V ≤ VIN ≤ 5V 300 100 1k 10k 100k CURRENT LIMIT SET RESISTOR (Ω) 1M LT1301 F8 Figure 8. Peak Switch Current vs. Current Limit Set Resistor 7 LT1301 APPLICATIONS INFORMATION Capacitor Selection Low ESR capacitors are required for both input and output of the LT1301. ESR directly affects ripple voltage and efficiency. For surface mount applications AVX TPS series tantalum capacitors are recommended. These have been specially designed for SMPS and have low ESR along with high surge current ratings. For through-hole applications Sanyo OS-CON capacitors offer extremely low ESR in a small size. Again, if peak switch current is reduced using the ILIM pin, capacitor requirements can be relaxed and smaller, higher ESR units can be used. Suggested capacitor sources are listed in Table 2. Diode Selection Best performance is obtained with a Schottky rectifier diode such as the 1N5817. Phillips Components makes this in surface mount as the PRLL5817. Motorola makes the MBRS130LT3 which is slightly better and also in surface mount. For lower output power a 1N4148 can be used although efficiency will suffer substantially. Layout Considerations The LT1301 is a high speed, high current device. The input capacitor must be no more than 0.2˝ from VIN (pin 6) and ground. Connect the PGND and GND (pins 8 and 1) together under the package. Place the inductor adjacent to SW (pin 7) and make the switch pin trace as short as possible. This keeps radiated noise to a minimum. TYPICAL APPLICATIONS N Four-Cell to 5V Converter L1 33µH 4 CELLS + C1 NC 100µF SHDN GND SHUTDOWN Step-Up Converter with Automatic Output Disconnect 470Ω L1* 10µH 1N5817 2N4403 5V, 200mA NC 2× AA CELL SELECT VIN SW LT1301 NC ILIM GND SENSE PGND 0.1µF + SHUTDOWN 100µF *SUMIDA CD54-100LC COILCRAFT DO3316-223 8 U W U U U + SW SENSE C2 100µF 1N5817 VIN ILIM LT1301 0.1µF SELECT PGND L2 33µH 5V OUTPUT 200mA 80 to 83% EFFICIENT AT ILOAD > 10mA + C3 100µF LT1301 TAO3 + 100µF SHDN LT1301 TA4 LT1301 TYPICAL APPLICATIONS N LCD Contrast Supply VIN 1.8V TO 6V T1 4 7 3 150K 10 8 2 9 1N5819 22µF CONTRAST VOUT –4V TO –29V 12mA MAXIMUM FROM 1.8V SUPPLY (77% EFFICIENT) 20mA MAXIMUM FROM 3V SUPPLY (83% EFFICIENT) + 100µF VIN 2V - 6V 1Ω 1N5817 120Ω VIN NC 0.1µF SHDN GND SENSE LT1301 SHUTDOWN T1 = COILTRONICS CTX110654-1 L1 = COILCRAFT D03316-473 U 1 + 35V VIN NC SENSE LT1301 NC SELECT PGND SW SHDN SHUTDOWN ILIM GND 12K T1 = DALE LPE-5047-AO45 (605) 665-9301 12K + 2.2µF PWM IN 0% TO 100% CMOS DRIVE 0V TO 5V LT1300 TA5 Low-Voltage CCFL Power Supply 9 TI 1 5 4 3 7 22pF 3kV 2 0.068µF CCFL ZTX849 WIMA MKP20 ZTX849 SELECT SW L1 47µH + 10µF 2N3904 ILIM PGND + 1µF 7.5K 1% 1N4148 0 - 5VDC IN INTENSITY ADJUST 100µA TO 2mA BULB CURRENT LT1300 TA6 9 LT1301 TYPICAL APPLICATIONS N 5V to – 5V Converter L1 33µH 2 3 –VOUT 5V 300mA 5V + 33µF NC 0.1µF NC SENSE GND VIN SELECT LT1301 OR LT1300 SW SHDN SHUTDOWN 4.99K 1% ILIM PGND 4.99K 1% L1 = COILTRONICS CTX33-4 10 U 1N965 1 1N4148 4 1N5817 + 33µF 5V LT1301 TA7 LT1301 PACKAGE DESCRIPTION 0.300 – 0.320 (7.620 – 8.128) 0.009 – 0.015 (0.229 – 0.381) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.020 (0.508) MIN ( +0.025 0.325 –0.015 +0.635 8.255 –0.381 ) 0.045 ± 0.015 (1.143 ± 0.381) 0.100 ± 0.010 (2.540 ± 0.254) 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0°– 8° TYP 0.016 – 0.050 0.406 – 1.270 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 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. U Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead Plastic DIP 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 0.400 (10.160) MAX 8 7 6 5 0.250 ± 0.010 (6.350 ± 0.254) 1 2 3 4 0.018 ± 0.003 (0.457 ± 0.076) N8 0392 S8 Package 8-Lead Plastic S0IC 0.189 – 0.197* (4.801 – 5.004) 0.053 – 0.069 (1.346 – 1.752) 8 0.004 – 0.010 (0.101 – 0.254) 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0. (3.810 – 3. 7 6 5 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) BSC 1 2 3 4 SO8 0294 11 LT1301 U.S. Area Sales Offices NORTHEAST REGION Linear Technology Corporation One Oxford Valley 2300 E. Lincoln Hwy.,Suite 306 Langhorne, PA 19047 Phone: (215) 757-8578 FAX: (215) 757-5631 Linear Technology Corporation 266 Lowell St., Suite B-8 Wilmington, MA 01887 Phone: (508) 658-3881 FAX: (508) 658-2701 SOUTHEAST REGION Linear Technology Corporation 17060 Dallas Parkway Suite 208 Dallas, TX 75248 Phone: (214) 733-3071 FAX: (214) 380-5138 CENTRAL REGION Linear Technology Corporation Chesapeake Square 229 Mitchell Court, Suite A-25 Addison, IL 60101 Phone: (708) 620-6910 FAX: (708) 620-6977 SOUTHWEST REGION Linear Technology Corporation 22141 Ventura Blvd. Suite 206 Woodland Hills, CA 91364 Phone: (818) 703-0835 FAX: (818) 703-0517 NORTHWEST REGION Linear Technology Corporation 782 Sycamore Dr. Milpitas, CA 95035 Phone: (408) 428-2050 FAX: (408) 432-6331 International Sales Offices FRANCE Linear Technology S.A.R.L. Immeuble "Le Quartz" 58 Chemin de la Justice 92290 Chatenay Malabry France Phone: 33-1-41079555 FAX: 33-1-46314613 GERMANY Linear Techonolgy GmbH Untere Hauptstr. 9 D-85386 Eching Germany Phone: 49-89-3197410 FAX: 49-89-3194821 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 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 SINGAPORE Linear Technology Pte. Ltd. 101 Boon Keng Road #02-15 Kallang Ind. Estates Singapore 1233 Phone: 65-293-5322 FAX: 65-292-0398 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 UNITED KINGDOM Linear Technology (UK) Ltd. The Coliseum, Riverside Way Camberley, Surrey GU15 3YL United Kingdom Phone: 44-276-677676 FAX: 44-276-64851 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 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977 LT/GP 0394 10K • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1994