LT1109ACS8-5#PBF

LT1109A Micropower DC/DC Converter Flash Memory VPP Generator Adjustable and Fixed 5V, 12V U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ Uses Off-the-Shelf Inductors Low Cost 8-Pin DIP or SO Package Fixed 5V or 12V Output or Adjustable Version Only Four External Components Required 360µA Standby Current Logic-Controlled Shutdown The LT1109A is a simple step-up DC/DC converter. The 8pin DIP or SOIC devices require only four external components to construct a complete DC/DC converter. Current drain is just 360µA at no load, making the device ideal for cost-sensitive applications where standby current must be kept to a minimum. The LT1109A-12 can deliver 12V at over 150mA from a 5V supply, enough power to program four flash memory chips simultaneously. The LT1109A-5 can deliver 5V at up to 110mA from a 2V input. The devices feature a shutdown pin that turns off the oscillator when taken low. The gatedoscillator design requires no frequency compensation components. High frequency 120kHz operation permits the use of small surface mount inductors and capacitors. UO APPLICATI ■ ■ ■ ■ ■ ■ ■ S Flash Memory VPP Generators 5V to 12V Converters 3.3V to 12V Converters Disk Drives PC Plug-In Cards Peripherals Battery-Powered Equipment UO TYPICAL APPLICATI All Surface Mount Flash Memory VPP Generator 1 +VIN 5V C1 22µF 10V 3 SW VIN SENSE LT1109ACS8-12 + 7 ** 13.0 MBRS130T3 SHUTDOWN PGND GND 4 5 12V 12.5 8 + VOUT 12V C2 47µF 20V OUTPUT VOLTAGE (V) L1* 33µH Output Voltage Output Current VIN = 5V 12.0 11.5 VOUT 2V/DIV SHUTDOWN 5V/DIV VIN = 4.5V 500µs/DIV 11.0 1109A TA03 10.5 * COILTRONICS CTX33-2 SUMIDA CD54-330LC ** 1 = PROGRAM 0 = SHUTDOWN 10.0 1109A TA01 0 50 250 100 150 200 OUTPUT CURRENT (mA) 300 1109A TA02 1 LT1109A W W W AXI U U ABSOLUTE RATI GS (Voltages Referred to GND Pin) Supply Voltage (VIN) ................................ – 0.4V to 20V SW Pin Voltage ........................................ – 0.4V to 50V Feedback Pin Voltage (LT1109A) ........................... 5.5V Shutdown Pin Voltage ........................................... 5.5V Switch Current .......................................................... 2A Maximum Power Dissipation ............................ 300mW Operating Temperature Range .................... 0°C to 70°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C W U U PACKAGE/ORDER I FOR ATIO TOP VIEW VIN 1 8 FB (SENSE)* NC 2 7 SHUTDOWN SW 3 6 NC PGND 4 5 GND N8 PACKAGE 8-LEAD PLASTIC DIP *FIXED VERSIONS ORDER PART NUMBER LT1109ACN8 LT1109ACN8-5 LT1109ACN8-12 TOP VIEW VIN 1 8 FB (SENSE)* NC 2 7 SHUTDOWN SW 3 6 NC PGND 4 1109A 1109A5 1109A1 TA = 25°C, VIN = 3V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS IQ Quiescent Current Switch Off VIN Input Voltage tON LT1109ACS8 LT1109ACS8-5 LT1109ACS8-12 TJMAX = 90°C, θJA = 150°C/W ELECTRICAL CHARACTERISTICS fOSC S8 PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO *FIXED VERSIONS TJMAX = 90°C, θJA = 130°C/W VOUT 5 GND ORDER PART NUMBER MIN ● ● 2 TYP MAX UNITS 360 500 µA 9 V Comparator Trip Point Voltage LT1109A ● 1.20 1.25 1.30 V Output Sense Voltage LT1109A-5; 2V ≤ VIN ≤ 5V LT1109A-12; 2V ≤ VIN ≤ 12V ● ● 4.75 11.52 5.00 12.00 5.25 12.55 V V Comparator Hysteresis LT1109A ● 8 12.5 mV Output Voltage Ripple LT1109A-5 LT1109A-12 ● ● 25 60 50 120 mV mV Oscillator Frequency 105 95 120 ● 135 155 kHz kHz 4.1 3.8 5.5 ● 6.9 7.4 µs µs 60 68 77 % 0.5 0.7 0.65 1.00 V V 1 10 µA Switch On Time DC Duty Cycle Full Load ● VCESAT Switch Saturation Voltage VIN = 3V, ISW = 650mA VIN = 5V, ISW = 1A ● Switch Leakage Current VSW = 12V VIH SHUTDOWN Pin High ● VIL SHUTDOWN Pin Low ● 0.8 V IIH SHUTDOWN Pin Input Current VSHUTDOWN ≥ 2.0V ● 10 µA IL SHUTDOWN Pin Input Current 0V ≤ VSHUTDOWN ≤ 0.8V ● 20 µA The ● denotes specifications which apply over the full operating temperature range. 2 2.0 V LT1109A U W TYPICAL PERFOR A CE CHARACTERISTICS Efficiency Oscillator Frequency VIN = 5V VOUT = 12V LOAD = 120mA L = 29µH 75 80 75 DUTY CYCLE (%) 140 FREQUENCY (kHz) 85 EFFICIENCY (%) Duty Cycle 80 160 90 120 100 80 70 4.2 4.4 4.6 4.8 5.0 5.2 5.4 INPUT VOLTAGE (V) 5.6 –25 0 25 50 TEMPERATURE (°C) 75 Switch Saturation Voltage 50 –50 100 –25 0 25 50 TEMPERATURE (°C) 75 100 1109A G03 Switch Saturation Voltage Switch On Time 8 0.7 1.4 ISW = 650mA VIN = 3V 0.6 VIN = 2V SWITCH ON TIME (µs) 7 0.5 0.8 VIN = 5V 0.6 VCESAT (V) 1.0 0.4 0.3 0.4 0.2 0.2 0.1 6 5 4 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0 –50 –25 ISWITCH (A) 0 25 50 TEMPERATURE (°C) 75 3 –50 100 –25 0 25 50 TEMPERATURE (°C) Quiescent Current 75 100 1109A G06 1109A G05 1109A G04 Quiescent Current 500 500 TA = 25°C 450 QUIESCENT CURRENT (µA) 0 QUIESCENT CURRENT (µA) VCESAT (V) 60 1109A G02 1109A G01 1.2 65 55 60 –50 5.8 70 400 350 300 250 200 –50 450 400 350 300 250 –25 0 25 50 TEMPERATURE (°C) 75 100 1109A G07 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 1109A G08 3 LT1109A U W TYPICAL PERFOR A CE CHARACTERISTICS Minimum/Maximum Oscillator Frequency vs tON LT1109A-12 Output Voltage 160 12.3 OSCILLATOR FREQUENCY (kHz) 150 OUTPUT VOLTAGE (V) 12.2 12.1 12.0 11.9 11.8 0°C ≤ TA ≤ 70°C 140 130 TA= 25°C 120 110 100 90 11.7 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 80 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 tON (µs) 125 1109A G10 1109A G09 W BLOCK DIAGRA S LT1109A-5, LT1109A-12 VIN LT1109A (Adjustable) SENSE VIN SW FB SW R2 250k 1.25V REF 1.25V REF + COMP A1 120kHz OSC – + COMP A1 Q1 120kHz OSC – DRIVER Q1 DRIVER R1* GND SHUTDOWN PGND GND SHUTDOWN PGND 1109A BD *LT1109A-5: R1 = 83k LT1109A-12: R1 = 29k 4 LT1109A U OPERATIO The LT1109A is a micropower step-up DC/DC converter. It uses Burst ModeTM operation to achieve micropower operation yet still deliver more than 2W of output power from a 5V supply. Circuit operation can be best understood by referring to the LT1109A block diagram. With SHUTDOWN high, comparator A1 compares the feedback (FB) pin voltage with the 1.25V reference signal. When FB Burst ModeTM is a trademark of Linear Technology Corporation U W U UO APPLICATI drops below 1.25V, A1 switches on the 120kHz oscillator. The driver amplifier boosts the signal level to drive the output NPN power switch. When the FB voltage is sufficient to trip A1, the oscillator is turned off. A low signal on the shutdown pin gates off the oscillator, overriding A1. With SHUTDOWN low, quiescent current remains at 360µA. S I FOR ATIO Inductor Selection A DC/DC converter operates by storing energy as magnetic flux in an inductor core, and then switching this energy into the load. To operate as an efficient energy transfer element, the inductor must fulfill three requirements: inductance value, saturation current and DC resistance. A fourth requirement is physical size. The inductors recommended with the LT1109A circuits are small, surface-mountable and are designed for switch-mode applications. Avoid using RF chokes or air core units since they have very low peak current ratings. The LT1109A works best in situations where the input voltage does not vary much since the device has no internal switch current limit function. For situations where the input voltage varies, such as battery inputs, the LT1107 or LT1111 is suggested instead. Capacitor Selection The output capacitor should be chosen on the basis of its equivalent series resistance (ESR) and capacitance value. Low ESR tantalum surface-mountable capacitors such as those made by AVX are well-suited for DC/DC converter applications. Inexpensive aluminum electrolytics may have excessive ESR, resulting in high output ripple. These should be avoided. Diode Selection Speed, forward drop, and leakage current are the three main considerations in selecting a diode for LT1109A converters. General purpose rectifiers such as the 1N4001 are unsuitable for use in any switching regulator application. Although they are rated at 1A, the switching time of a 1N4001 is in the 10µs to 50µs range. At best, efficiency will be severely compromised if this diode is used; at worst, the circuit may not work at all. The 1N5818 is an ideal choice for LT1109A circuits. Surface-mountable versions, such as the MBRS130T3, are available as well. Table 1. Inductor Manufacturers MANUFACTURER PART NUMBERS Coiltronics International 984 S.W. 13th Court Pompano Beach, FL 33069 305-781-8900 Surface Mount OCTA-PACTM Series Sumida Electric Co., Ltd. 637 E. Golf Road, Suite 209 Arlington Heights, IL 60005 708-956-0666 CD54 CD105 Surface Mount OCTA-PACTM is a trademark of Coiltronics International Table 2. Capacitor Manufacturers MANUFACTURER PART NUMBERS AVX Myrtle Beach, SC 29578 803-946-0690 TPS Series Philips Components 2001 W. Blue Heron Blvd. P.O. Box 10330 Riviera Beach, FL 33404 407-881-3200 49MC Series Sanyo Video Components 1201 Sanyo Avenue San Diego, CA 92073 619-661-6322 OS-CON Series 5 LT1109A UO TYPICAL APPLICATI S 3.3V Powered Flash Memory VPP Generator VIN 3.3V 20µH* MBRS130T3 12V 60mA + 22µF 1 VIN 3 SW 8 SENSE LT1109A-12 7 SHUTDOWN GND PGND 4 5 + 33µF** 25V SHUTDOWN * COILTRONICS CTX20-1 SUMIDA CD54-220LC ** AVX TPS SERIES 1109A TA04 2V Powered Flash Memory VPP Generator VIN 2V 10µH* MBRS130T3 12V 35mA + 22µF 1 VIN 3 SW 8 SENSE LT1109A-12 7 SHUTDOWN GND PGND 4 5 + 33µF** 25V SHUTDOWN * COILTRONICS CTX10-1 SUMIDA CD54-100LC ** AVX TPS SERIES 6 1109A TA05 LT1109A UO TYPICAL APPLICATI S 2V to 5V Converter MBRS130T3 10µH* VIN 2V 5V 110mA + 22µF 1 3 SW 8 SENSE VIN LT1109A-12 7 SHUTDOWN GND PGND 4 5 + 33µF** 10V SHUTDOWN * COILTRONICS CTX10-1 SUMIDA CD54-100LC ** AVX TPS SERIES 1109A TA06 5V to 12V Converter with Shutdown to 0V at Output 2k VIN 5V 10µH* MBRS130T3 + 2N4403 22µF 1 VIN 3 SW 8 SENSE VOUT 12V 110mA LT1109A-12 7 SHUTDOWN GND PGND 4 5 + 47µF** 20V + 1µF SHUTDOWN * COILTRONICS CTX33-2 SUMIDA CD54-330LC 1109A TA07 ** AVX TPS SERIES 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. 7 LT1109A U PACKAGE DESCRIPTIO Dimensions are in inches (millimeters) unless otherwise noted. N8 Package 8-Lead Plastic DIP 0.300 – 0.320 (7.620 – 8.128) 0.045 – 0.065 (1.143 – 1.651) +0.025 0.325 –0.015 8.255 +0.635 –0.381 0.130 ± 0.005 (3.302 ± 0.127) 8 7 6 5 0.065 (1.651) TYP 0.009 – 0.015 (0.229 – 0.381) ( 0.400 (10.160) MAX 0.250 ± 0.010 (6.350 ± 0.254) 0.045 ± 0.015 (1.143 ± 0.381) ) 0.100 ± 0.010 (2.540 ± 0.254) 0.125 (3.175) MIN 0.020 (0.508) MIN 1 2 3 4 0.018 ± 0.003 (0.457 ± 0.076) N8 0392 S8 Package 8-Lead Plastic SOIC 0.189 – 0.197 (4.801 – 5.004) 8 0.010 – 0.020 × 45° (0.254 – 0.508) 0.016 – 0.050 0.406 – 1.270 6 5 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 0.254) 0.008 – 0.010 (0.203 – 0.254) 0°– 8° TYP 7 0.014 – 0.019 (0.355 – 0.483) 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157 (3.810 – 3.988) 0.050 (1.270) BSC 1 2 3 4 SO8 0392 8 Linear Technology Corporation sn1109A 1109afs LT/GP 0493 10K REV 0 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977  LINEAR TECHNOLOGY CORPORATION 1993