POWER LOSS (W) LTC3407-3 Dual Synchronous, 1.8V/0.8A and 3.3V/0.8A 2.25MHz Step-Down DC/DC Regulator FEATURES DESCRIPTION n Very Low Quiescent Current: Only 40A The LTC 3407-3 is a dual, constant frequency, synchro- n 1.8V at 800mA/3.3V at 800mA nous step down DC/DC converter. Intended for low power n High Ef ciency: Up to 95% applications, it operates from 3.3V to 5.5V input voltage n 2.25MHz Constant Frequency Operation range and has a constant 2.25MHz switching frequency, n High Switch Current: 1.2A on Each Channel allowing the use of tiny, low cost capacitors and inductors n No Schottky Diodes Required with a pro le 1.0mm. Internal synchronous 0.35, 1.2A n Low R Internal Switches: 0.35 power switches provide high ef ciency without the need DS(ON) n V : 3.3V to 5.5V for external Schottky diodes. IN n Current Mode Operation for Excellent Line A user selectable mode input is provided to allow the user and Load Transient Response to trade-off noise ripple for low power ef ciency. Burst n Short-Circuit Protected Mode operation provides high ef ciency at light loads, n Low Dropout Operation: 100% Duty Cycle while pulse-skipping mode provides low noise ripple at n Ultralow Shutdown Current: I < 1A Q light loads. n Power-On Reset Output n To further maximize battery life, the P-channel MOSFETs Externally Synchronizable Oscillator n are turned on continuously in dropout (100% duty cycle), Small Thermally Enhanced 3mm 3mm DFN Package and both channels draw a total quiescent current of only APPLICATIONS 40A. In shutdown, the device draws <1A. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks n PDAs/Palmtop PCs of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, n Digital Cameras 6611131. n Cellular Phones n Portable Media Players n PC Cards n Wireless and DSL Modems TYPICAL APPLICATION LTC3407-3 Ef ciency/Power Loss 100 1 V = 3.3V OUT V IN 90 3.3V TO 5.5V 10F 100k 80 RUN2 V RUN1 V = 1.8V IN 0.1 OUT MODE/SYNC POR RESET 70 LTC3407-3 60 2.2H 2.2H V V V = 3.3V OUT2 OUT1 0.01 OUT SW2 SW1 3.3V 1.8V V = 1.8V 50 OUT V V OUT1 OUT2 40 10F 10F GND 0.001 34073 TA01 30 V = 5V IN 20 Burst Mode OPERATION NOTE: IN DROPOUT, THE OUTPUT TRACKS THE INPUT VOLTAGE NO LOAD ON OTHER CHANNEL 10 0.000 1 10 100 1000 Figure 1. 1.8V/3.3V at 800mA Step-Down Regulators LOAD CURRENT (mA) 34073 TA01b 34073fb 1 EFFICIENCY (%)LTC3407-3 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) V Voltages .................................................0.3V to 6V IN TOP VIEW V , V Voltages ..................... 0.3V to V + 0.3V OUT1 OUT2 IN RUN1, RUN2 Voltages .................................0.3V to V IN V 1 10 V OUT1 OUT2 RUN1 2 9 RUN2 MODE/SYNC Voltage ....................................0.3V to V IN V IN 11 3 8 POR SW1, SW2 Voltage ........................... 0.3V to V + 0.3V IN SW1 4 7 SW2 POR Voltage ................................................. 0.3V to 6V GND 5 6 MODE/ SYNC Ambient Operating Temperature DD PACKAGE Range (Note 2) ......................................... 40C to 85C 10-LEAD (3mm 3mm) PLASTIC DFN Junction Temperature (Note 5) ............................. 125C T = 125C, = 40C/W, = 10C/W JMAX JA JC EXPOSED PAD (PIN 11) IS PGND, MUST BE SOLDERED TO PCB GND Storage Temperature Range ................... 65C to 125C ORDERING INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3407EDD-3 PBF LTC3407EDD-3 TRPBF LCJB 10-Lead (3mm 3mm) Plastic DFN 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: