POWER LOSS (W) LT8641 65V, 3.5A Synchronous Step-Down Silent Switcher with 2.5A Quiescent Current FEATURES DESCRIPTION n Silent Switcher Architecture The LT 8641 step-down regulator features Silent Switcher n Ultralow EMI Emissions architecture designed to minimize EMI emissions while n Spread Spectrum Frequency Modulation delivering high efficiency at frequencies up to 3MHz. n Assembled in a 3mm 4mm QFN, the monolithic con- High Efficiency at High Frequency n struction with integrated power switches and inclusion of Up to 95% Efficiency at 1MHz, 12V to 5V IN OUT n all necessary circuitry yields a solution with a minimal PCB Up to 94% Efficiency at 2MHz, 12V to 5V IN OUT n footprint. An ultralow 2.5A quiescent currentwith the Wide Input Voltage Range: 3V to 65V n output in full regulationenables applications requiring 3.5A Maximum Continuous Output, highest efficiency at very small load currents. Transient 5A Peak Transient Output n response remains excellent and output voltage ripple is Ultralow Quiescent Current Burst Mode Operation n below 10mV at any load, from zero to full current. 2.5A I Regulating 12V to 3.3V P-P Q IN OUT n Output Ripple < 10mV P-P The LT8641 allows high V to low V conversion IN OUT n Fast Minimum Switch On-Time: 35ns at high frequency with a fast minimum top switch on- n Low Dropout Under All Conditions: 130mV at 1A time of 35ns. Operation is safe in overload even with a n Safely Tolerates Inductor Saturation in Overload saturatedinductor. n Adjustable and Synchronizable: 200kHz to 3MHz Essential features are included and easy to use: An open- n Peak Current Mode Operation drain PG pin signals when the output is in regulation. n Output Soft-Start and Tracking The SYNC/MODE pin selects between Burst Mode, pulse- n Small 18-Lead 3mm 4mm QFN skipping, or spread spectrum mode, and also allows syn- n AEC-Q100 Qualified for Automotive Applications chronization to an external clock. Soft-start and tracking functionality is accessed via the TR/SS pin. An accurate APPLICATIONS enable threshold can be set using the EN/UV pin and a resistor at the RT pin programs switch frequency. n Automotive and Industrial Supplies n All registered trademarks and trademarks are the property of their respective owners. Protected General Purpose Step-Down by U.S. patents, including 8823345. n GSM Power Supplies TYPICAL APPLICATION 12V to 5V Efficiency IN OUT 100 2.600 5V 3.5A Step-Down Converter 95 2.275 V IN 5.5V TO 65V 90 EFFICIENCY 1.950 4.7F EN/UV V V IN1 IN2 1F 1F 85 1.625 GND1 GND2 80 1.300 LT8641 PG BST 4.7H 0.1F V OUT 10nF 75 0.975 5V SYNC/MODE SW POWER LOSS 3.5A TR/SS BIAS 0.650 70 1F 4.7pF 1M 1MHz, L = 3.3H 65 0.325 47F 2MHz, L = 2.2H INTV FB CC 41.2k 3MHz, L = 1.5H 191k 0 60 RT GND 0.5 1 1.5 2 2.5 3 3.5 LOAD CURRENT (A) f = 1MHz 8641 TA01b SW 8641 TA01a Rev. C 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8641 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV ................................................................65V IN PG .............................................................................42V BIAS ..........................................................................25V 20 19 18 17 FB, TR/SS ................................................................4V BIAS 1 16 TR/SS SYNC/MODE Voltage ...............................................6V INTV 2 15 RT CC Operating Junction Temperature Range (Note 2) BST 3 EN/UV 14 22 V 4 V 13 LT8641E ............................................. 40C to 125C IN1 IN2 SW LT8641I .............................................. 40C to 125C 21 GND1 6 SW 11 GND2 LT8641J ............................................. 40C to 150C 7 8 9 10 LT8641H ............................................ 40C to 150C Storage Temperature Range .................. 65C to 150C UDC PACKAGE 18-LEAD (3mm 4mm) PLASTIC QFN = 40C/W, ) = 12C/W (NOTE 3) JA JC(PAD EXPOSED PAD (PINS 21, 22) ARE SW, SHOULD BE SOLDERED TO PCB NOTE: PINS 5 AND 12 ARE REMOVED. CONFIGURATION DOES NOT MATCH JEDEC 20-LEAD PACKAGE OUTLINE ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT8641EUDC PBF LT8641EUDC TRPBF LGSN 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8641IUDC PBF LT8641IUDC TRPBF LGSN 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8641HUDC PBF LT8641HUDC TRPBF LGSN 18-Lead (3mm 4mm) Plastic QFN 40C to 150C AUTOMOTIVE PRODUCTS** LT8641IUDC WPBF LT8641IUDC WTRPBF LGSN 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8641JUDC WPBF LT8641JUDC WTRPBF LGSN 18-Lead (3mm 4mm) Plastic QFN 40C to 150C LT8641HUDC WPBF LT8641HUDC WTRPBF LGSN 18-Lead (3mm 4mm) Plastic QFN 40C to 150C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. **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. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. A PARAMETER CONDITIONS MIN TYP MAX UNITS l Minimum Input Voltage 2.6 3.0 V V Quiescent Current V = 0V 0.75 3 A IN EN/UV l 0.75 10 A V = 2V, Not Switching, V = 0V 1.7 4 A EN/UV SYNC l 1.7 10 A V = 2V, Not Switching, V = 2V 0.3 0.5 mA EN/UV SYNC l V Current in Regulation V = 0.8V, V = 6V, Output Load = 100A 17 50 A IN OUT IN l V = 0.8V, V = 6V, Output Load = 1mA 200 350 A OUT IN Rev. C 2 For more information www.analog.com GND1 FB SW PG SW GND GND2 SYNC/MODE