POWER LOSS (W) LT8636/LT8637 42V, 5A/7A Peak Synchronous Step-Down Silent Switcher with 2.5A Quiescent Current FEATURES DESCRIPTION n Silent Switcher Architecture The LT 8636/LT8637 synchronous step-down regulator n features Silent Switcher architecture designed to minimize Ultralow EMI Emissions n EMI emissions while delivering high efficiency at high Optional Spread Spectrum Modulation n switching frequencies. Peak current mode control with High Efficiency at High Frequency n a 30ns minimum on-time allows high step-down ratios Up to 96% Efficiency at 1MHz, 12V to 5V IN OUT even at high switching frequencies. n Up to 95% Efficiency at 2MHz, 12V to 5V IN OUT n Wide Input Voltage Range: 3.4V to 42V The LT8636s ultralow 2.5A quiescent currentwith the n 5A Maximum Continuous, 7A Peak Transient Output output in full regulationenables applications requiring n Ultralow Quiescent Current Burst Mode Operation highest efficiency at very small load currents. The LT8637 n 2.5A I Regulating 12V to 3.3V (LT8636) has external compensation to enable current sharing and Q IN OUT n Output Ripple < 10mV fast transient response at high switching frequencies. A P-P n External Compensation: Fast Transient Response CLKOUT pin enables synchronizing other regulators to and Current Sharing (LT8637) the LT8636/LT8637. n Fast Minimum Switch On-Time: 30ns Burst Mode operation enables ultralow standby current n Low Dropout Under All Conditions: 100mV at 1A consumption, forced continuous mode can control fre- n Forced Continuous Mode quency harmonics across the entire output load range, or n Adjustable and Synchronizable: 200kHz to 3MHz spread spectrum operation can further reduce EMI emis- n Output Soft-Start and Power Good sions. Soft-start and tracking functionality is accessed n Small 20-Lead 4mm 3mm LQFN Package via the TR/SS pin, and an accurate input voltage UVLO n AEC-Q100 Qualified for Automotive Applications threshold 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, including 8823345. APPLICATIONS n Automotive and Industrial Supplies n General Purpose Step-Down TYPICAL APPLICATION 5V, 5A Step-Down Converter 12V to 5V Efficiency IN OUT V IN 100 3.2 5.7V TO 42V EN/UV 95 2.8 V V 4.7F IN IN 1F 1F EFFICIENCY 90 2.4 GND GND 85 2.0 LT8636 BST 80 1.6 0.1F 3.3H V OUT SW 5V 75 1.2 5A BIAS POWER LOSS INTV 70 0.8 CC 10pF 1M 1F 1MHz, L = 2.7H RT FB 100F 65 0.4 2MHz, L = 1.5H 3MHz, L = 1H 41.2k GND 243k 60 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 LOAD CURRENT (A) f = 1MHz 8636 TA01a SW 8636 TA01b Rev. C 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8636/LT8637 ABSOLUTE MAXIMUM RATINGS (Note 1) Operating Junction Temperature Range (Note 2) V , EN/UV, PG ..........................................................42V IN LT8636E/LT8637E ............................. 40C to 125C BIAS ..........................................................................25V LT8636J/LT8637J .............................. 40C to 150C FB, TR/SS ................................................................4V LT8636H ............................................ 40C to 150C SYNC/MODE Voltage ...............................................6V LT8636MP ......................................... 55C to 150C Storage Temperature Range .................. 65C to 150C Maximum Reflow (Package Body) Temperature .....260C PIN CONFIGURATION LT8636 LT8637 TOP VIEW TOP VIEW 20 19 18 17 20 19 18 17 PG 1 16 CLKOUT PG 1 16 CLKOUT BIAS 2 15 SYNC/MODE BIAS 2 15 SYNC/MODE INTV 3 14 EN/UV CC INTV 3 14 EN/UV CC 21 21 GND GND GND 4 13 GND GND 4 13 GND NC 5 12 NC NC 5 12 NC V 6 11 V IN IN V 6 11 V IN IN 7 8 9 10 7 8 9 10 LQFN PACKAGE LQFN PACKAGE 20-LEAD (4mm 3mm 0.94mm) 20-LEAD (4mm 3mm 0.94mm) JEDEC BOARD: = 41C/W, = 50.6C/W, JA JC(top) JEDEC BOARD: = 41C/W, = 50.6C/W, JA JC(top) = 8.0C/W, (NOTE 3) JC(pad) = 8.0C/W, (NOTE 3) JC(pad) DEMO BOARD: = 26C/W, = 0.8C/W JA JT DEMO BOARD: = 26C/W, = 0.8C/W JA JT EXPOSED PAD (PIN 21) IS GND, SHOULD BE SOLDERED TO PCB EXPOSED PAD (PIN 21) IS GND, SHOULD BE SOLDERED TO PCB ORDER INFORMATION PACKAGE MSL PART NUMBER PART MARKING* FINISH CODE PAD FINISH TYPE** RATING TEMPERATURE RANGE LT8636EV PBF 40C to 125C LT8636JV PBF 40C to 150C 8636 LT8636HV PBF 40C to 150C LQFN (Laminate Package e4 Au (RoHS) 3 with QFN Footprint) LT8636MPV PBF 55C to 150C LT8637EV PBF 40C to 125C 8637 LT8637JV PBF 40C to 150C Rev. C 2 For more information www.analog.com FB BST FB SW SW TR/SS SW RT FB BST V SW C TR/SS SW SW RT