POWER LOSS (mW) LT3970 Series 40V, 350mA Step-Down Regulator with 2.5A Quiescent Current and Integrated Diodes FEATURES DESCRIPTION n Low Ripple Burst Mode Operation The LT 3970 is an adjustable frequency monolithic buck n 2.5A I at 12V to 3.3V switching regulator that accepts a wide input voltage Q IN OUT n Output Ripple < 5mV range up to 40V, and consumes only 2.5A of quiescent P-P n Wide Input Voltage Range: 4.2V to 40V Operating current. A high efficiency switch is included on the die n Adjustable Switching Frequency: 200kHz to 2.2MHz along with the catch diode, boost diode, and the neces- n Integrated Boost and Catch Diodes sary oscillator, control and logic circuitry. Low ripple Burst n 350mA Output Current Mode operation maintains high efficiency at low output n Fixed Output Voltages: 3.3V, 3.42V, 5V currents while keeping the output ripple below 5mV in 1.8A I at 12V a typical application. Current mode topology is used for Q IN n Accurate 1V Enable Pin Threshold fast transient response and good loop stability. A catch n Low Shutdown Current: I = 0.7A diode current limit provides protection against shorted Q n Internal Sense Limits Catch Diode Current outputs and overvoltage conditions. An enable pin with n Power Good Flag accurate threshold is available, producing a low shutdown n Output Voltage: 1.21V to 25V current of 0.7A. A power good flag signals when V OUT n Internal Compensation reaches 90% of the programmed output voltage. The n Small 10-Pin MSOP and (3mm 2mm) DFN Packages LT3970 is available in small 10-pin MSOP and 3mm n AEC-Q100 Qualified for Automotive Applications 2mm DFNpackages. All registered trademarks and trademarks are the property of their respective owners. APPLICATIONS n Automotive Battery Regulation n Power for Portable Products n Industrial Supplies TYPICAL APPLICATION Efficiency 5V Step-Down Converter 90 1000 V = 12V IN V IN 6V TO 40V 80 100 0.22F V BOOST IN LT3970 22H V 10 OUT 70 5V OFF ON EN SW 350mA PG BD 1 60 22pF 1M RT FB 22F 2.2F GND 316k 226k 50 0.1 3490 TA01a f = 600kHz 0.01 40 0.01 0.1 1 10 100 LOAD CURRENT (mA) 3970 TA01b Rev. D 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT3970 Series ABSOLUTE MAXIMUM RATINGS (Note 1) V , EN Voltage .........................................................40V Operating Junction Temperature Range (Note 2) IN BOOST Pin Voltage ...................................................55V E-, I-grade .......................................... 40C to 125C BOOST Pin Above SW Pin .........................................30V H-grade .............................................. 40C to 150C FB/V , RT Voltage ...................................................6V Storage Temperature Range .................. 65C to 150C OUT PG, BD Voltage .........................................................30V Lead Temperature (Soldering, 10 sec) MS Only ............................................................300C PIN CONFIGURATION TOP VIEW TOP VIEW *FB/V 1 10 RT OUT *FB/V 1 10 RT 2 9 OUT EN PG EN 2 9 PG 11 3 V 8 BD IN V 3 8 BD IN GND GND 4 7 BOOST GND 4 7 BOOST GND 5 6 SW GND 5 6 SW MS PACKAGE 10-LEAD PLASTIC MSOP DDB PACKAGE 10-LEAD (3mm 2mm) PLASTIC DFN = 100C/W JA = 76C/W JA EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB *FB for LT3970, V for LT3970-3.3, LT3970-3.42, LT3970-5. OUT Rev. D 2 For more information www.analog.com