LT8609/LT8609A/LT8609B 42V, 3A Synchronous Step-Down Regulator with 2.5A Quiescent Current FEATURES DESCRIPTION n Wide Input Voltage Range: 3.0V to 42V The LT 8609/LT8609A/LT8609B is a compact, high effi- n Ultralow Quiescent Current Burst Mode Operation: ciency, high speed synchronous monolithic step-down n <2.5A I Regulating 12V to 3.3V switching regulator that consumes only 1.7A of non- Q IN OUT n Output Ripple <10mV switching quiescent current. The LT8609/LT8609A/ P-P n High Efficiency 2MHz Synchronous Operation: LT8609B can deliver 3A of continuous current. Burst Mode n >93% Efficiency at 1A, 5V from 12V operation enables high efficiency down to very low output OUT IN n 3A Maximum Continuous Output currents while keeping the output ripple below 10mV . P-P n Fast Minimum Switch-On Time: 45ns A SYNC pin allows synchronization to an external clock, or n LT8609A Available in Fixed 3.3V and 5V Output spread spectrum modulation for low EMI operation. Internal n Adjustable and Synchronizable: 200kHz to 2.2MHz compensation with peak current mode topology allows the n Spread Spectrum Frequency Modulation for Low EMI use of small inductors and results in fast transient response n Allows Use of Small Inductors and good loop stability. The EN/UV pin has an accurate n Low Dropout 1V threshold and can be used to program V UVLO or to IN n Peak Current Mode Operation shut down the part. Acapacitor on the TR/SS pin programs n Accurate 1V Enable Pin Threshold the output voltage ramp rate during start-up while the PG n Internal Compensation flag signals when V is within 8.5% on the adjustable OUT n Output Soft-Start and Tracking output parts or 7.5% on the fixed output parts of the n Small 10-Lead MSOP Package, 16-Lead MSOP Pack- programmed output voltage as well as fault conditions. age, or 10-Lead 3mm 3mm DFN Package with Side The LT8609A has slower switch edges for lower EMI emis- Wettable Flanks sions. The LT8609B operates in pulse-skipping mode only. n AEC-Q100 Qualified for Automotive Applications PULSE-SKIPPING MODE, BurstMode OPERATION SWITCH EDGE SPEED APPLICATIONS LT8609 Both Fast n GSM Transceivers LT8609A Both Medium n General Purpose Step-Down LT8609B Pulse-Skipping Fast n Low EMI Step-Down All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION 12V to 5V Efficiency IN OUT 100 L = 2.2H 5V, 2MHz Step-Down 95 f = 2MHz SW V 90 IN V BST IN 6V TO 40V 85 4.7F ON OFF 0.1F EN/UV 2.2H V OUT SYNC SW 5V 80 10pF 3A LT8609A 75 INTV CC 70 TR/SS PG 1M RT FB 65 1F 18.2k 187k 22F GND 60 55 8609 TA01a 50 0.00 0.50 1.00 1.50 2.00 2.50 3 I (A) OUT 8609 TA01b Rev. J 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8609/LT8609A/LT8609B ABSOLUTE MAXIMUM RATINGS (Note 1) V , EN/UV, PG ..........................................................42V Operating Junction Temperature Range (Note 2) IN FB, TR/SS ...................................................................4V LT8609E/LT8609AE/LT8609BE ......... 40C to 125C SYNC, V .................................................................6V LT8609I/LT8609AI/LT8609BI ............ 40C to 125C OUT LT8609H/LT8609AH .......................... 40C to 150C LT8609AJ .......................................... 40C to 150C Storage Temperature Range .................. 65C to 150C PIN CONFIGURATION LT8609A LT8609/LT8609A LT8609B TOP VIEW TOP VIEW TOP VIEW 1 BST 16 EN/UV NC 2 15 NC BST 1 10 EN/UV BST 1 10 EN/UV 3 SW 14 V IN SW 2 9 V SW 2 9 V IN IN 17 11 11 NC 4 13 NC INTV 3 8 PG INTV 3 8 PG CC CC 5 GND GND GND INTV 12 PG CC RT 4 7 TR/SS RT 4 7 TR/SS RT 6 11 TR/SS SYNC 5 6 FB NC 5 6 FB 7 SYNC 10 FB GND 8 9 FB MSE PACKAGE MSE PACKAGE 10-LEAD PLASTIC MSOP 10-LEAD PLASTIC MSOP MS PACKAGE = 40C/W = 40C/W 16-LEAD PLASTIC MSOP JA JA EXPOSED PAD (PIN 11) IS GND, EXPOSED PAD (PIN 11) IS GND, = 40C/W, (PAD) = 10C/W JA JC MUST BE SOLDERED TO PCB MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB LT8609/LT8609A LT8609-3.3/LT8609-5 TOP VIEW TOP VIEW BST 1 10 EN/UV BST 1 10 EN/UV SW 2 9 V SW 2 9 V IN IN 11 11 INTV 3 8 PG INTV 3 8 PG CC CC GND GND RT 4 7 TR/SS RT 4 7 TR/SS SYNC 5 6 FB SYNC 5 6 V OUT DDM PACKAGE DDM PACKAGE 10-LEAD (3mm 3mm) PLASTIC SIDE WETTABLE DFN 10-LEAD (3mm 3mm) PLASTIC SIDE WETTABLE DFN = 45C/W, = 10C/W = 45C/W, = 10C/W JA JC JA JC EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8609EMSE PBF LT8609EMSE TRPBF LTGRW 10-Lead Plastic MSOP 40C to 125C LT8609IMSE PBF LT8609IMSE TRPBF LTGRW 10-Lead Plastic MSOP 40C to 125C LT8609HMSE PBF LT8609HMSE TRPBF LTGRW 10-Lead Plastic MSOP 40C to 150C LT8609AEMSE PBF LT8609AEMSE TRPBF LTGVR 10-Lead Plastic MSOP 40C to 125C LT8609AIMSE PBF LT8609AIMSE TRPBF LTGVR 10-Lead Plastic MSOP 40C to 125C LT8609AJMSE PBF LT8609AJMSE TRPBF LTGVR 10-Lead Plastic MSOP 40C to 150C LT8609AHMSE PBF LT8609AHMSE TRPBF LTGVR 10-Lead Plastic MSOP 40C to 150C LT8609BEMSE PBF LT8609BEMSE TRPBF LTGZY 10-Lead Plastic MSOP 40C to 125C Rev. J 2 For more information www.analog.com