LT1534/LT1534-1 Ultralow Noise 2A Switching Regulators FEATURES DESCRIPTIO n Greatly Reduced Conducted and Radiated EMI The LT 1534/LT1534-1 are a new class of switching regula- n Low Switching Harmonic Content tor designed to reduce conducted and radiated electromag- n Independent Control of Switch Voltage and netic interference (EMI). Ultralow noise and EMI are achieved Current Slew Rates by providing user control of the output switch slew rates. n 2A Current Limited Power Switch Voltage and current slew rates can be independently pro- n Regulates Positive and Negative Voltages grammed to optimize switcher harmonic content versus n 20kHz to 250kHz Oscillator Frequency efficiency. The LT1534/LT1534-1 can reduce high frequency n Easily Synchronized to External Clock harmonic power by as much as 40dB with only minor losses n Wide Input Voltage Range: 2.7V to 23V in efficiency. n Low Shutdown Current: 12m A Typical The LT1534/LT1534-1 utilize a current mode architecture n Easier Layout than with Conventional Switchers optimized for low noise boost topologies. The ICs include a 2A power switch along with all necessary oscillator, control U and protection circuitry. Unique error amp circuitry can APPLICATIO S regulate both positive and negative voltages. The internal n Precision Instrumentation Systems oscillator may be synchronized to an external clock for more n Isolated Supplies for Industrial Automation accurate placement of switching harmonics. Protection fea- n Medical Instruments tures include cycle-by-cycle current limit protection, under- n Wireless Communications voltage lockout and thermal shutdown. n Single Board Data Acquisition Systems Low minimum supply voltage and low supply current during shutdown make the LT1534/LT1534-1 well suited for por- table applications. The LT1534/LT1534-1 are available in the 16-pin narrow SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION L1 L3 3.3V 1N5817 50m H 50m H A B 5V 650mA 15 C1 + C IN + + C2 47F 33F 10W V 12 IN 2 47F 5V Output Noise (BW = 100MHz) 6.3V 6.3V SHDN COL 2 4 OPTIONAL SYNC 1nF L2 3300pF 3 PGND 5 A C LT1534-1 T 24k 14 50mV/DIV R 16.9k VSL 6 R T 24k 13 R CSL 7.5k 7 11 1534 TA01 V FB C B GND NFB 220pF 6.8k 2mV/DIV 2.49k C : MATSUSHITA ECGCOJB330 1,8, 10 IN C1, C2: MATSUSHITA ECGCOJB47O 9,16 15nF L1, L3: COILTRONICS CTX50-4 L2: COILCRAFT B08T (28nH) OR PC TRACE 1534 TA02 10m s/DIV Figure 1. Low Noise 3.3V to 5V Boost Converter 1 U ULT1534/LT1534-1 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Voltage (V ) .................................................. 30V Operating Junction Temperature Range IN Switch Voltage (COL) .............................................. 35V LT1534C ................................................ 0 C to 125 C SHDN Pin Voltage .................................................... 30V LT1534I ............................................ 40 C to 125 C Feedback Pin Current (FB) .................................... 10mA Maximum Junction Temperature .......................... 125 C Negative Feedback Pin Current (NFB) .................. 10mA Storage Temperature Range ................. 65 C to 150 C Lead Temperature (Soldering, 10 sec.)................. 300 C PACKAGE/ORDER INFORMATION ORDER PART ORDER PART TOP VIEW NUMBER NUMBER TOP VIEW GND 1 16 GND COL 2 15 NC 1 16 PGND V IN LT1534CS LT1534CS-1 PGND 3 14 COL 2 15 COL R VSL LT1534IS LT1534IS-1 SYNC 4 13 *NC 3 14 V R CSL IN C 5 12 SYNC 4 13 R SHDN T VSL R 6 11 V C 5 12 R T C T CSL FB 7 10 NFB R 6 11 SHDN T GND 8 9 GND FB 7 10 V C NFB 8 9 GND S PACKAGE 16-LEAD PLASTIC SO S PACKAGE **FOUR CORNER PINS ARE FUSED TO INTERNAL 16-LEAD PLASTIC SO DIE ATTACH PADDLE FOR HEAT SINKING. *DO NOT CONNECT CONNECT THESE FOUR PINS TO EXPANDED PC LANDS FOR PROPER HEAT SINKING. T = 125 C, q = 100 C/ W JMAX JA T = 125 C, q = 50 C/ W JMAX JA Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C, V = 5V, V = 0.9V, V = V . COL, SHDN, NFB, all other pins open A IN C FB REF unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Supply and Protection V Recommended Operating Range l 2.7 23 V IN V Minimum Input Voltage l 2.55 2.7 V IN(MIN) I Operating Supply Current 2.7V V 23V, R , R , R = 17k l 12 30 mA VIN IN VSL CSL T I Shutdown Supply Current 2.7V V 23V, V = 0V l 12 50 m A VIN(OFF) IN SHDN 2.7V V 23V, V = 0V 12 30 m A IN SHDN V Shutdown Threshold 2.7V V 23V l 0.4 0.8 1.2 V SHDN IN I Shutdown Input Current 2 m A SHDN Error Amplifiers V Reference Voltage Measured at Feedback Pin 1.235 1.250 1.265 V REF l 1.215 1.250 1.275 V I Feedback Input Current V = V l 250 900 nA FB FB REF FB Reference Voltage Line Regulation 2.7V V 23V l 0.003 0.03 %/V REG IN 2 U W U U WWW