POWER LOSS (W) LT8636 42V, 5A/7A Peak Synchronous Step-Down Silent Switcher with 2.5A Quiescent Current FEATURES DESCRIPTION n Silent Switcher Architecture The LT 8636 synchronous step-down regulator features n Silent Switcher architecture designed to minimize EMI Ultralow EMI Emissions n emissions while delivering high efficiency at high switch- Optional Spread Spectrum Modulation n ing frequencies. Peak current mode control with a 30ns High Efficiency at High Frequency n minimum on-time allows high step-down ratios even at Up to 96% Efficiency at 1MHz, 12V to 5V IN OUT 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. A CLKOUT n 2.5A I Regulating 12V to 3.3V pin enables synchronizing other regulators to the LT8636. Q IN OUT n Output Ripple < 10mV P-P Burst Mode operation enables ultralow standby current n Fast Minimum Switch On-Time: 30ns consumption, forced continuous mode can control fre- n Low Dropout Under All Conditions: 100mV at 1A quency harmonics across the entire output load range, or n Forced Continuous Mode spread spectrum operation can further reduce EMI emis- n Adjustable and Synchronizable: 200kHz to 3MHz sions. Soft-start and tracking functionality is accessed n Output Soft-Start and Power Good via the TR/SS pin, and an accurate input voltage UVLO n Small 20-Lead 4mm 3mm LQFN Package threshold can be set using the EN/UV pin. n AEC-Q100 Qualified for Automotive Applications 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 100 3.2 V IN 5.7V TO 42V 95 2.8 EN/UV V V 4.7F IN IN EFFICIENCY 90 2.4 1F 1F GND GND 85 2.0 LT8636 BST 80 1.6 0.1F 3.3H V OUT SW 5V 75 1.2 5A POWER LOSS BIAS 70 0.8 INTV CC 10pF 1M 1MHz, L = 2.7H 1F 65 0.4 2MHz, L = 1.5H RT FB 100F 3MHz, L = 1H 60 0 41.2k GND 243k 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 LOAD CURRENT (A) 8636 TA01b f = 1MHz 8636 TA01a SW Rev. B 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8636 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV, PG ..........................................................42V IN BIAS ..........................................................................25V FB, TR/SS ................................................................4V 20 19 18 17 SYNC/MODE Voltage ...............................................6V PG 1 16 CLKOUT Operating Junction Temperature Range (Note 2) BIAS 2 15 SYNC/MODE LT8636E ............................................ 40C to 125C INTV 3 14 EN/UV CC 21 LT8636J............................................. 40C to 150C GND GND 4 13 GND LT8636H ............................................ 40C to 150C NC 5 12 NC Storage Temperature Range .................. 65C to 150C Maximum Reflow (Package Body) Temperature .....260C V 6 11 V IN IN 7 8 9 10 LQFN PACKAGE 20-LEAD (4mm 3mm 0.94mm) JEDEC BOARD: = 41C/W, = 1.1C/W, JA JT = 50.6C/W, = 8.0C/W, (NOTE 3) JC(top) JC(pad) DEMO BOARD: = 26C/W JA 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 LQFN (Laminate Package LT8636JV PBF 8636 e4 Au (RoHS) 3 40C to 150C with QFN Footprint) LT8636HV PBF 40C to 150C AUTOMOTIVE PRODUCTS*** LT8636EV WPBF 40C to 125C LT8636JV WPBF 40C to 150C LQFN (Laminate Package 8636 e4 Au (RoHS) 3 with QFN Footprint) LT8636JV WTRPBF 40C to 150C LT8636HV WPBF 40C to 150C Contact the factory for parts specified with wider operating temperature Recommended PCB Assembly and Manufacturing Procedures ranges. *Device temperature grade is identified by a label on the Package and Tray Drawings shippingcontainer. Pad finish code is per IPC/JEDEC J-STD-609. Parts ending with PBF are RoHS and WEEE compliant. **The LT8636 package has the same dimensions as a standard 4mm 3mm QFN package. ***Versions of this part are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. These models are designated with a W suffix. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for thesemodels. Rev. B 2 For more information www.analog.com FB BST FB SW TR/SS SW SW RT