POWER LOSS (W) LT8640/LT8640-1 42V, 5A Synchronous Step-Down Silent Switcher with 2.5A Quiescent Current FEATURES DESCRIPTION n Silent Switcher Architecture The LT 8640/LT8640-1 step-down regulator features Silent n Ultralow EMI Emissions Switcher architecture designed to minimize EMI emissions n Spread Spectrum Frequency Modulation while delivering high efficiency at frequencies up to 3MHz. n High Efficiency at High Frequency An ultralow 2.5A quiescent currentwith the output in n Up to 96% Efficiency at 1MHz, 12V to 5V full regulationenables applications requiring highest IN OUT n Up to 95% Efficiency at 2MHz, 12V to 5V efficiency at very small load currents. IN OUT n Wide Input Voltage Range: 3.4V to 42V The LT8640/LT8640-1 allows high V to low V conversion IN OUT n 5A Maximum Continuous Output, 7A Peak at high frequency with a fast minimum top switch on-time of Transient Output 30ns. The SYNC/MODE pin selects between Burst Mode n Ultralow Quiescent Current Burst Mode Operation operation, spread spectrum mode, synchronization to n 2.5A I Regulating 12V to 3.3V Q IN OUT an external clock, and either pulse-skipping (LT8640) or n Output Ripple < 10mV P-P forced continuous mode (LT8640-1). n Fast Minimum Switch On-Time: 30ns n SYNC/ 150C INTERNAL Low Dropout Under All Conditions: 100mV at 1A PACKAGE MODE 0 V COMP GRADE CLKOUT CAPS C n Forced Continuous Mode (LT8640-1 Only) Pulse- n Safely Tolerates Inductor Saturation in Overload LT8640 QFN Internal Yes No No Skipping n Adjustable and Synchronizable: 200kHz to 3MHz LT8640-1 QFN FCM Internal Yes No No n Peak Current Mode Operation LT8640S LQFN FCM Internal No Yes Yes n Output Soft-Start and Tracking LT8643S LQFN FCM External No Yes Yes n Small 18-Lead 3mm 4mm QFN and Side Wettable QFN LT8640S-2 LQFN FCM Internal Yes Yes No n AEC-Q100 Qualified for Automotive Applications LT8643S-2 LQFN FCM External Yes Yes No APPLICATIONS All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 8823345. n Automotive and Industrial Supplies n General Purpose Step-Down n GSM Power Supplies TYPICAL APPLICATION 12V to 5V Efficiency IN OUT 100 3.00 5V 5A Step-Down Converter V IN 95 2.63 5.5V TO 42V 4.7F EN/UV 90 EFFICIENCY 2.25 V V IN1 IN2 1F 1F GND1 GND2 85 1.88 LT8640/ PG LT8640-1 BST 80 1.50 0.1F 3.3H V OUT 10nF 5V SYNC/MODE SW 75 1.13 5A TR/SS BIAS POWER LOSS 1F 70 0.75 4.7pF 1M 1MHz, L = 3.3H 47F INTV FB CC 65 0.38 2MHz, L = 2.2H 41.2k 243k RT GND 3MHz, L = 1H 60 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 f = 1MHz SW 8640 TA01a LOAD CURRENT (A) 8640 TA01b Rev. D 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT8640/LT8640-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V , EN/UV, PG ..........................................................42V IN BIAS ..........................................................................25V FB, TR/SS ................................................................4V SYNC/MODE Voltage ...............................................6V 20 19 18 17 Operating Junction Temperature Range (Note 2) 1 16 BIAS TR/SS LT8640E/LT8640-1E .......................... 40C to 125C INTV 2 15 RT CC LT8640I/LT8640-1I ............................ 40C to 125C BST 3 EN/UV 14 LT8640J/LT8640-1J ........................... 40C to 150C 22 V 4 V IN1 13 IN2 SW LT8640H/LT8640-1H ......................... 40C to 150C Storage Temperature Range ......................65 to 150C 21 GND1 6 SW 11 GND2 7 8 9 10 UDC AND UDCF PACKAGES 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 LT8640EUDC PBF LT8640EUDC TRPBF LGNJ 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8640IUDC PBF LT8640IUDC TRPBF LGNJ 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8640HUDC PBF LT8640HUDC TRPBF LGNJ 18-Lead (3mm 4mm) Plastic QFN 40C to 150C LT8640EUDC-1 PBF LT8640EUDC-1 TRPBF LGVT 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8640IUDC-1 PBF LT8640IUDC-1 TRPBF LGVT 18-Lead (3mm 4mm) Plastic QFN 40C to 125C LT8640HUDC-1 PBF LT8640HUDC-1 TRPBF LGVT 18-Lead (3mm 4mm) Plastic QFN 40C to 150C LT8640EUDCF PBF LT8640EUDCF TRPBF LHJK 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 125C LT8640IUDCF PBF LT8640IUDCF TRPBF LHJK 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 125C LT8640JUDCF PBF LT8640JUDCF TRPBF LHJK 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 150C LT8640EUDCF-1 PBF LT8640EUDCF-1 TRPBF LHGX 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 125C LT8640IUDCF-1 PBF LT8640IUDCF-1 TRPBF LHGX 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 125C LT8640JUDCF-1 PBF LT8640JUDCF-1 TRPBF LHGX 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 150C AUTOMOTIVE PRODUCTS** LT8640JUDCF WPBF LT8640JUDCF WTRPBF LHJK 18-Lead (3mm 4mm) Plastic Side Wettable QFN 40C to 150C LT8640JUDCF-1 WPBF LT8640JUDCF-1 WTRPBF LHGX 18-Lead (3mm 4mm) Plastic Side Wettable 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. Rev. D 2 For more information www.analog.com GND1 FB SW PG SW GND GND2 SYNC/MODE