POWER LOSS (mW) LTC3542 500mA, 2.25MHz Synchronous Step-Down DC/DC Converter FEATURES DESCRIPTION High Ef ciency: Up to 96% The LTC 3542 is a high ef ciency monolithic synchronous High Peak Switch Current: 1000mA buck converter using a constant frequency, current mode Low Output Ripple (<20mV Typical) architecture. Supply current during operation is only P-P Burst Mode Operation: Only 26A 26A, dropping to <1A in shutdown. The 2.5V to 5.5V Very Low Quiescent Current: Only 26A input voltage range makes the LTC3542 ideally suited for 2.5V to 5.5V Input Voltage Range single Li-Ion battery-powered applications. 100% duty 2.25MHz Constant Frequency Operation cycle provides low dropout operation, extending battery 1MHz to 3MHz External Frequency Synchronization life in portable systems. The output voltage is adjustable Low Dropout Operation: 100% Duty Cycle from 0.6V to V . Internal power switches are optimized IN No Schottky Diode Required to provide high ef ciency and eliminate the need for an Internal Soft-Start Limits Inrush Current external Schottky diode. 0.6V Reference Allows Low Output Voltages Switching frequency is internally set at 2.25MHz, allowing Shutdown Mode Draws <1A Supply Current the use of small surface mount inductors and capacitors, 2% Output Voltage Accuracy and it can synchronize to an external clock signal with a Current Mode Operation for Excellent Line and Load frequency range of 1MHz to 3MHz through the MODE/ Transient Response SYNC pin. The LTC3542 is speci cally designed to work Overtemperature Protected well with ceramic output capacitors, achieving very low Available in 6-Lead 2mm 2mm DFN and Small TSOT output voltage ripple and a small PCB footprint. The LTC3542 can be con gured for the power saving Burst APPLICATIONS Mode Operation. For reduced noise and RF interference, Cellular Telephones the MODE/SYNC pin can be con gured for pulse skipping Wireless and DSL Modems operation. Digital Cameras , LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology MP3 Players Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, PDAs and Other Handheld Devices 6611131, 5994885. Ef ciency and Power Loss vs Output Current TYPICAL APPLICATION 100 1000 V = 3.6V IN 90 V = 1.8V OUT 2.2H V 80 OUT V IN 100 V SW 1.8V IN 2.7V TO 5.5V 70 C 22pF IN 500mA 10F 60 LTC3542 CER 150k 50 10 RUN V FB C 40 OUT MODE/SYNC 75k 10F 30 CER GND 1 3542 TA01a 20 10 0 0.1 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3542 TA01b 3542fa 1 EFFICIENCY (%)LTC3542 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Supply Voltage (V ) ........................... 0.3V to 6V Junction Temperature (Note 7) ............................. 125C IN V , RUN Voltages .......................................0.3V to V Storage Temperature Range ................... 65C to 150C FB IN MODE Voltage ................................0.3V to (V + 0.3V) Lead Temperature (Soldering, 10 sec) IN SW Voltage ....................................0.3V to (V + 0.3V) TSOT-23 ............................................................300C IN Operating Temperature Range (Note 2) Re ow Peak Body Temperature (DFN) .................. 260C LTC3542E ............................................ 40C to 85C LTC3542I ........................................... 40C to 125C PIN CONFIGURATION TOP VIEW TOP VIEW V 1 6 RUN FB V 1 6 SW IN MODE/ 7 V 2 5 IN SYNC GND 2 5 MODE/SYNC GND 3 4 SW V 3 4 RUN FB S6 PACKAGE DC PACKAGE 6-LEAD PLASTIC TSOT-23 6-LEAD (2mm 2mm) PLASTIC DFN T = 125C, = 215C/W JMAX JA T = 125C, = 102C/W, = 20C/W (SOLDERED TO A 4-LAYER BOARD, NOTE 3) JMAX JA JC EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3542EDC PBF LTC3542EDC TRPBF LCFR 6-Lead (2mm 2mm) Plastic DFN 40C to 85C LTC3542IDC PBF LTC3542IDC TRPBF LCFR 6-Lead (2mm 2mm) Plastic DFN 40C to 125C LTC3542ES6 PBF LTC3542ES6 TRPBF LCFS 6-Lead Plastic TSOT-23 40C to 85C LTC3542IS6 PBF LTC3542IS6 TRPBF LCFS 6-Lead Plastic TSOT-23 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: