LTC3405A-1.5/LTC3405A-1.8 1.5V, 1.8V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT FEATURES DESCRIPTIO High Efficiency: Up to 93% The LTC 3405A-1.5/LTC3405A-1.8 are high efficiency Very Low Quiescent Current: Only 20A monolithic synchronous buck regulators using a constant During Operation frequency, current mode architecture. Supply current 300mA Output Current at V = 3V during operation is only 20A and drops to <1A in IN 2.5V to 5.5V Input Voltage Range shutdown. The 2.5V to 5.5V input voltage range makes the 1.5MHz Constant Frequency Operation LTC3405A-1.5/LTC3405A-1.8 ideally suited for single No Schottky Diode Required Li-Ion battery-powered applications. 100% duty cycle Low Dropout Operation: 100% Duty Cycle provides low dropout operation, extending battery life in Stable with Ceramic Capacitors portable systems. Shutdown Mode Draws <1A Supply Current Switching frequency is internally set at 1.5MHz, allowing 3% Output Voltage Accuracy the use of small surface mount inductors and capacitors. Current Mode Operation for Excellent Line and Load Transient Response The LTC3405A-1.5/LTC3405A-1.8 are specifically designed Overtemperature Protected to work well with ceramic output capacitors, achieving TM Low Profile (1mm) ThinSOT Package very low output voltage ripple and a small PCB footprint. U The internal synchronous switch increases efficiency and APPLICATIO S eliminates the need for an external Schottky diode. The Cellular Telephones LTC3405A-1.5/LTC3405A-1.8 are available in a low profile Personal Information Appliances (1mm) ThinSOT package. Wireless and DSL Modems For adjustable output voltage, refer to the LTC3405A data Digital Still Cameras sheet. MP3 Players , LTC and LT are registered trademarks of Linear Technology Corporation. Portable Instruments ThinSOT is a trademark of Linear Technology Corporation. Protected by U.S. Patents, including 6580258, 5481178. TYPICAL APPLICATIO 100 V = 2.7V IN 90 4.7H* V V IN OUT 4 3 80 V = 3.6V 1.8V IN 2.7V V SW IN 300mA TO 5.5V C ** IN V = 4.2V IN LTC3405A-1.8 C ** 4.7F OUT 1 70 4.7F CER RUN V = 5.5V IN CER 6 5 MODE V OUT 60 GND 3405A1518 F01 2 50 *MURATA LQH3C4R7M34 40 **TAIYO YUDEN JMK212BJ475MG 0.1 1 10 100 1000 OUTPUT CURRENT (mA) 3405A1518 F01b Figure 1a. High Efficiency Step-Down Converter Figure 1b. Efficiency vs Load Current 3405a1518fa 1 EFFICIENCY (%) U ULTC3405A-1.5/LTC3405A-1.8 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) Input Supply Voltage .................................. 0.3V to 6V ORDER PART TOP VIEW MODE, RUN, V Voltages....................... 0.3V to V NUMBER OUT IN SW Voltage .................................. 0.3V to (V + 0.3V) RUN 1 6 MODE IN LTC3405AES6-1.5 P-Channel Switch Source Current (DC) ............. 400mA GND 2 5 V OUT LTC3405AES6-1.8 SW 3 4 V IN N-Channel Switch Sink Current (DC) ................. 400mA Peak SW Sink and Source Current .................... 630mA S6 PACKAGE S6 PART MARKING 6-LEAD PLASTIC TSOT-23 Operating Temperature Range (Note 2) .. 40C to 85C T = 125C, = 250C/ W JMAX JA LTZQ Junction Temperature (Note 3)............................ 125C LTZP Storage Temperature Range ................ 65C to 150C Consult LTC Marketing for parts specified with wider operating temperature ranges. Lead Temperature (Soldering, 10 sec)................. 300C ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25C. A V = 3.6V unless otherwise specified. IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS I Peak Inductor Current V = 3V, V = 90%, Duty Cycle < 35% 375 500 625 mA PK IN OUT V Regulated Output Voltage LTC3405A-1.5, MODE = 3.6V 1.455 1.500 1.545 V OUT LTC3405A-1.8, MODE = 3.6V 1.746 1.800 1.854 V V Output Overvoltage Lockout V = V V 2.5 7.8 13 % OVL OVL OVL OUT V Output Voltage Line Regulation V = 2.5V to 5.5V 0.04 0.4 %/V OUT IN V Output Voltage Load Regulation 0.5 % LOADREG V Input Voltage Range 2.5 5.5 V IN I Input DC Bias Current (Note 4) S Pulse Skipping Mode V = 90%, MODE = 3.6V, I = 0A 300 400 A OUT LOAD Burst Mode Operation V = 103%, MODE = 0V, I = 0A 20 35 A OUT LOAD Shutdown V = 0V, V = 4.2V 0.1 1 A RUN IN f Oscillator Frequency V = 100% 1.2 1.5 1.8 MHz OSC OUT V = 0V 170 kHz OUT R R of P-Channel FET I = 100mA 0.7 0.85 PFET DS(ON) SW R R of N-Channel FET I = 100mA 0.6 0.90 NFET DS(ON) SW I SW Leakage V = 0V, V = 0V or 5V, V = 5V 0.01 1 A LSW RUN SW IN V RUN Threshold 0.3 1 1.5 V RUN I RUN Leakage Current 0.01 1 A RUN V MODE Threshold 0.3 1.5 2 V MODE I MODE Leakage Current 0.01 1 A MODE Burst Mode is a registered trademark of Linear Technology Corporation. Note 3: T is calculated from the ambient temperature T and power J A dissipation P according to the following formula: Note 1: Absolute Maximum Ratings are those values beyond which the life D of a device may be impaired. LTC3405A: T = T + (P )(250C/W) J A D Note 2: The LTC3405AE is guaranteed to meet performance specifications Note 4: Dynamic supply current is higher due to the gate charge being from 0C to 70C. Specifications over the 40C to 85C operating delivered at the switching frequency. temperature range are assured by design, characterization and correlation with statistical process controls. 3405a1518fa 2 U WWW