LT8609/LT8609A/LT8609B 42V, 2A/3A Peak 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 ef- n Ultralow Quiescent Current Burst Mode Operation: ficiency, 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/LT8609B P-P n High Efficiency 2MHz Synchronous Operation: can deliver 2A of continuous current with peak loads of n >93% Efficiency at 1A, 5V from 12V 3A(<1sec). Burst Mode operation enables high efficiency OUT IN n 2A Maximum Continuous Output, 3A Peak down to very low output currents while keeping the output Transient Output ripple below 10mV . A SYNC pin allows synchronization to P-P n Fast Minimum Switch-On Time: 45ns an external clock, or spread spectrum modulation for low EMI n Adjustable and Synchronizable: 200kHz to 2.2MHz operation. Internal compensation with peak current mode n Spread Spectrum Frequency Modulation for Low EMI topology allows the use of small inductors and results in fast n Allows Use of Small Inductors transient response and good loop stability. The EN/UV pin n Low Dropout has an accurate 1V threshold and can be used to program n Peak Current Mode Operation V UVLO or to shut down the part. Acapacitor on the TR/SS IN n Accurate 1V Enable Pin Threshold pin programs the output voltage ramp rate during start-up n Internal Compensation while the PG flag signals when V is within 8.5% of the OUT n Output Soft-Start and Tracking programmed output voltage as well as fault conditions. The n Small 10-Lead or 16-Lead MSOP Package LT8609A has slower switch edges for lower EMI emissions. The LT8609B operates in pulse-skipping mode only. APPLICATIONS PULSE-SKIPPING MODE, BurstMode OPERATION SWITCH EDGE SPEED n GSM Transceivers LT8609 Both Fast n General Purpose Step-Down LT8609A Both Medium n Low EMI Step-Down LT8609B Pulse-Skipping Fast All registered trademarks and trademarks are the property of their respective owners. TYPICAL APPLICATION 12V to 5V Efficiency IN OUT 100 5V, 2MHz Step-Down 95 90 V IN V BST IN 5.5V TO 40V 85 4.7F ON OFF EN/UV 0.1F 2.2H V OUT 80 SYNC SW 5V 10pF 2A LT8609 75 INTV CC 70 TR/SS PG 1M 65 RT FB 1F 18.2k 187k 22F 60 GND 55 8609 TA01a f = 2MHz SW 50 0 0.50 1.00 1.50 2.00 2.50 I (A) OUT 8609 TA01b 8609fg 1 For more information www.linear.com/LT8609 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 ............. 40 to 125C SYNC Voltage ...........................................................6V LT8609I/LT8609AI/LT8609BI ................ 40 to 125C LT8609H/LT8609AH ..............................40 to 150C Storage Temperature Range ......................65 to 150C PIN CONFIGURATION TOP VIEW LT8609B LT8609/LT8609A BST 1 16 EN/UV TOP VIEW TOP VIEW NC 2 15 NC BST 1 10 EN/UV BST 1 10 EN/UV SW 3 14 V IN SW 2 9 V NC 4 17 13 NC SW 2 9 V IN IN 11 11 INTV 3 8 PG INTV 5 GND 12 PG INTV 3 8 PG CC CC CC GND GND RT 6 11 TR/SS RT 4 7 TR/SS RT 7 TR/SS 4 SYNC 7 10 FB NC 5 6 FB 6 FB SYNC 5 GND 8 9 FB MSE PACKAGE MSE PACKAGE MS PACKAGE 10-LEAD PLASTIC MSOP 10-LEAD PLASTIC MSOP 16-LEAD PLASTIC MSOP = 40C/W JA = 40C/W JA = 40C/W, = 10C/W EXPOSED PAD (PIN 11) IS GND, JA JC(PAD) EXPOSED PAD (PIN 11) IS GND, EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB MUST BE SOLDERED TO PCB MUST BE SOLDERED TO PCB