POWER LOSS (W) LTC3407-4 Dual Synchronous, 800mA, 2.25MHz Step-Down DC/DC Regulator FEATURES DESCRIPTION n High Ef ciency: Up to 95% The LTC 3407-4 is a dual, constant frequency, synchro- n Very Low Quiescent Current: Only 40A nous step down DC/DC converter. Intended for low power n 2.25MHz Constant Frequency Operation applications, it operates from 2.5V to 5.5V input voltage n High Switch Current: 1.2A on Each Channel range and has a constant 2.25MHz switching frequency, n No Schottky Diodes Required allowing the use of tiny, low cost capacitors and induc- n Low R Internal Switches: 0.35 tors with a pro le 1mm. Each output voltage is adjust- DS(ON) n Current Mode Operation for Excellent Line able from 0.6V to 5V. Internal synchronous 0.35, 1.2A and Load Transient Response power switches provide high ef ciency without the need n Short-Circuit Protected for external Schottky diodes. n Low Dropout Operation: 100% Duty Cycle A user selectable mode input is provided to allow the user n Ultralow Shutdown Current: I < 1A Q to trade-off noise ripple for low power ef ciency. Burst n Output Voltages from 5V down to 0.6V Mode operation provides high ef ciency at light loads, n Power-On Reset Output while pulse-skipping mode provides low noise ripple at n Externally Synchronizable Oscillator light loads. n Small Thermally Enhanced MSOP and 3mm 3mm To further maximize battery life, the P-channel MOSFETs DFN Packages are turned on continuously in dropout (100% duty cycle), APPLICATIONS and both channels draw a total quiescent current of only 40A. In shutdown, the device draws <1A. n PDAs/Palmtop PCs n Digital Cameras The LTC3407-4 is identical to the LTC3407-2 except for n Cellular Phones the reduced power-on reset delay time. n Portable Media Players L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective n PC Cards owners. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. n Wireless and DSL Modems TYPICAL APPLICATION LTC3407-4 Ef ciency/Power Loss Curve V * IN 2.5V TO 5.5V R5 100 1 C1 100k 10F RUN2 V RUN1 IN 90 MODE/SYNC POR RESET 80 L2 L1 0.1 LTC3407-4 2.2H 2.2H 70 V V OUT2 OUT1 2.5V SW2 SW1 1.8V 60 800mA C5, 22pF C4, 22pF 800mA 50 0.01 40 V V FB1 FB2 30 R4 R2 GND C3 C2 0.001 R3 R1 887k 604k 20 10F 10F 280k 301k 10 C1, C2, C3: TAIYO YUDEN JMK316BJ106ML L1, L2: MURATA LQH32CN2R2M33 0 0.0001 3407 TA01 *V CONNECTED TO V FOR V 2.8V 0.1 1 10 100 1000 OUT IN IN LOAD CURRENT (mA) Figure 1. 2.5V/1.8V at 800mA Step-Down Regulators 34074 TA02 34074fa 1 EFFICIENCY (%)LTC3407-4 (Note 1) ABSOLUTE MAXIMUM RATINGS V Voltages .................................................0.3V to 6V Ambient Operating Temperature IN V , V Voltages .......................... 0.3V to V + 0.3V Range (Note 2) ......................................... 40C to 85C FB1 FB2 IN RUN1, RUN2 Voltages .................................0.3V to V Junction Temperature (Note 5) ............................. 125C IN MODE/SYNC Voltage ....................................0.3V to V Storage Temperature Range ................... 65C to 125C IN SW1, SW2 Voltage ........................... 0.3V to V + 0.3V Lead Temperature (Soldering, 10 sec) IN POR Voltage ................................................. 0.3V to 6V LTC3407EMSE-4 only ....................................... 300C Re ow Peak Body Temperature ............................ 260C PIN CONFIGURATION TOP VIEW TOP VIEW 10 V 1 V FB1 FB2 V 1 10 V FB1 FB2 RUN1 2 9 RUN2 RUN1 2 9 RUN2 V IN 11 11 V 3 8 POR 3 8 POR IN SW1 4 7 SW2 SW1 4 7 SW2 MODE/ GND 5 6 GND SYNC 5 6 MODE/ MSE PACKAGE SYNC 10-LEAD PLASTIC MSOP DD PACKAGE T = 125C, = 45C/W, = 10C/W JMAX JA JC 10-LEAD (3mm 3mm) PLASTIC DFN EXPOSED PAD (PIN 11) IS PGND, MUST BE SOLDERED TO GND T = 125C, = 45C/W, = 10C/W JMAX JA JC EXPOSED PAD (PIN 11) IS PGND, MUST BE SOLDERED TO GND ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3407EDD-4 PBF LTC3407EDD-4 TRPBF LCJD 10-Lead (3mm 3mm) Plastic DFN 40C to 85C LTC3407EMSE-4 PBF LTC3407EMSE-4 TRPBF LTCJC 10-Lead (3mm 3mm) Plastic MSOP 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: