POWER LOSS (W) LT8642S 18V, 10A Synchronous Step-Down Silent Switcher 2 FEATURES DESCRIPTION n Silent Switcher 2 Architecture The LT 8642S synchronous step-down regulator fea- n Ultralow EMI Emissions On Any PCB tures second generation Silent Switcher architecture n Eliminates PCB Layout Sensitivity designed to minimize EMI emissions while delivering n Internal Bypass Capacitors Reduce Radiated EMI high efficiency at high switching frequencies. This n Optional Spread Spectrum Modulation includes the integration of bypass capacitors to opti- n High Efficiency at High Frequency mize all the fast current loops inside and make it easy n Up to 96% Efficiency at 1MHz, 12V to 3.3V to achieve advertised EMI performance by eliminating IN OUT n Up to 95% Efficiency at 2MHz, 12V to 3.3V layout sensitivity. This performance makes the LT8642S IN OUT n Wide Input Voltage Range: 2.8V to 18V ideal for noise sensitive applications and environments. n 10A Output Current The fast, clean, low-overshoot switching edges enable n External Compensation: Fast Transient Response high efficiency operation even at high switching frequen- and Current Sharing cies, leading to a small overall solution size. Peak current n Low Quiescent Current Burst Mode Operation mode control with a 25ns minimum on-time allows high n 240A I Regulating 12V to 1.2V Q IN OUT step down ratios even at high switching frequencies. n Output Ripple < 10mV P-P External compensation via the V pin allows for fast C n Fast Minimum Switch On-Time: 25ns transient response at high switching frequencies. The n Low Dropout Under All Conditions: 50mV at 1A V pin also enables current sharing and a CLKOUT pin C n Forced Continuous Mode enables synchronizing other regulators to the LT8642S. n Adjustable and Synchronizable: 200kHz to 3MHz n Burst Mode operation enables low standby current con- Output Soft-Start and Power Good n sumption, forced continuous mode can control frequency Small 24-Lead 4mm 4mm LQFN Package harmonics across the entire output load range, or spread APPLICATIONS spectrum operation can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the n Server Power Applications SS pin, and an accurate input voltage UVLO threshold n General Purpose Step-Down can be set using the EN/UV pin. All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents 8823345. 12V to 1.2V Efficiency TYPICAL APPLICATION IN OUT 100 3.2 V = 3.3V BIAS 1.2V 10A Step-Down Converter 95 2.8 0.28H V OUT V 90 2.4 IN V SW 1.2V IN 2.8V TO 18V 10A 85 2.0 10F EN/UV EFFICIENCY 11k LT8642S 47pF 100k 80 1.6 V C 220F RT FB 75 1.2 2 150pF 17.8k 100k POWER LOSS GND 70 0.8 8642S TA01a 1MHz, L = 0.56H f = 2MHz SW 65 0.4 2MHz, L = 0.28H 3MHz, L = 0.28H 60 0 1 2 3 4 5 6 7 8 9 10 LOAD CURRENT (A) 8642S TA01b Rev 0 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8642S ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV, PG, BIAS ................................................18V IN FB, SS .........................................................................4V SYNC/MODE Voltage ...............................................6V Operating Junction Temperature Range (Note 2) 24 23 22 21 20 19 LT8642SE .......................................... 40C to 125C BIAS 1 18 RT LT8642SI ........................................... 40C to 125C 25 26 INTV 2 17 EN/UV CC GND GND Storage Temperature Range .................. 65C to 150C GND 3 16 GND Maximum Reflow (Package Body) Temperature ...260C V 4 15 V IN IN 27 28 V 5 GND GND 14 V IN IN V 6 13 V IN IN 7 8 9 10 11 12 LQFN PACKAGE 24-LEAD (4mm 4mm 0.94mm) JEDEC BOARD: = 38C/W, = 7C/W (NOTE 3) JA JC(PAD) DEMO BOARD: = 24C/W JA EXPOSED PAD (PINS 2528) ARE GND, SHOULD BE SOLDERED TO PCB ORDER INFORMATION