LTC3555/LTC3555-X High Efficiency USB Power Manager + Triple Step-Down DC/DC FEATURES DESCRIPTION Power Manager The LTC 3555 family are highly integrated USB com- n patible power management and battery charger ICs for High Efficiency Switching PowerPath Controller Li-Ion/Polymer battery applications. They include a high with Bat-Track Adaptive Output Control n efficiency current limited switching PowerPath manager Programmable USB or Wall Current Limit with automatic load prioritization, a battery charger, an ideal (100mA/500mA/1A) n diode and three general purpose synchronous step-down Full Featured Li-Ion/Polymer Battery Charger n switching regulators. 1.5A Maximum Charge Current n Internal 180m Ideal Diode + External Ideal Diode The LTC3555 family limits input current to either 100mA Controller Powers Load in Battery Mode or 500mA for USB applications or 1A for adapter-powered n Low No-Load Quiescent Current when Powered from applications. Unlike linear chargers, the LTC3555 familys BAT (<32A) switching architecture transmits nearly all of the power available from the USB port to the load with minimal loss DC/DCs and heat which eases thermal constraints in small spaces. n Triple High Efficiency Step-Down DC/DCs (1A/400mA/400mA I ) OUT Two of the three general purpose switching regulators can n All Regulators Operate at 2.25MHz provide up to 400mA and the third can deliver 1A. The n 2 Dynamic Voltage Scaling on Two Outputs entire product can be controlled via I C or simple I/O. The 2 n I C or Independent Enable, V Controls OUT LTC3555-1/LTC3555-3 versions offer instant-on power n Low No-Load Quiescent Current: 20A delivery to the portable product even with a very low battery n 28-Pin (4mm 5mm 0.75mm) QFN Package voltage. The LTC3555-3 version also has a reduced charger float voltage of 4.100V for battery safety and longevity. APPLICATIONS The LTC3555 family is available in the low profile 28-pin (4mm 5mm 0.75mm) QFN surface mount package. n HDD-Based MP3 Players, PDAs, GPS, PMPs n L, LT, LTC, LTM Linear Technology, the Linear logo and Burst Mode are registered trademarks Portable Medical Products and PowerPath and Bat-Track are trademarks of Linear Technology Corporation. All other n Handheld Instrumentation trademarks are the property of their respective owners. Protected by U.S. Patents, including 6522118 and 6404251. n Other USB-Based Handheld Products TYPICAL APPLICATION High Efficiency PowerPath Manager and Triple Step-Down Regulator Switching Regulator Efficiency to USB/WALL TO OTHER USB COMPLIANT System Load (P /P ) 4.35V TO 5.5V OUT BUS LOADS STEP-DOWN 100 REGULATOR CC/CV 90 0V OPTIONAL BATTERY CURRENT 80 CHARGER CONTROL BAT = 4.2V 70 CHARGE + 60 Li-Ion T BAT = 3.3V LTC3555/LTC3555-X 50 3.3V/25mA RTC/LOW 40 ALWAYS ON LDO POWER LOGIC 30 0.8V TO 3.6V/400mA 1 MEMORY TRIPLE 20 5 HIGH EFFICIENCY 0.8V TO 3.6V/400mA V = 5V ENABLE BUS 2 I/O STEP-DOWN I = 0mA 10 CONTROLS BAT SWITCHING 0.8V TO 3.6V/1A 10x MODE 3 CORE 0 REGULATORS RST 0.01 0.1 1 PROCESSOR 2 2 I (A) 2 OUT I C PORT I C 3555 TA01b 3555 TA01 3555fe 1 For more information www.linear.com/LTC3555 EFFICIENCY (%)LTC3555/LTC3555-X ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Notes 1, 2, 3) V (Transient) t < 1ms, TOP VIEW BUS Duty Cycle < 1% .......................................... 0.3V to 7V 28 27 26 25 24 23 V , V , V , V (Static), DV , IN1 IN2 IN3 BUS CC LDO3V3 1 22 GATE FB1, FB2, FB3, NTC, BAT, SCL, SDA, CLPROG 2 21 CHRG RST3, CHRG ................................................. 0.3V to 6V NTC 3 20 PROG EN1, EN2, EN3 ................................ 0.3V to V +0.3V OUT FB2 4 19 FB1 29 I , I ...................0.3V to MAX (V , V BAT) LIM0 LIM1 BUS OUT V 5 18 V IN2 IN1 I ....................................................................3mA CLPROG SW2 6 17 SW1 I , I ............................................................50mA EN2 7 16 EN1 RST3 CHRG DV 8 15 RST3 I ........................................................................2mA CC PROG 9 10 11 12 13 14 I ...................................................................30mA LDO3V3 I , I ........................................................... 600mA SW1 SW2 UFD PACKAGE I , I , I , I ..................................................2A SW SW3 BAT VOUT 28-LEAD (4mm 5mm) PLASTIC QFN Junction Temperature ........................................... 125C T = 125C, = 37C/W JMAX JA EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB Operating Temperature Range (Note 2)....40C to 85C Storage Temperature Range .................. 65C to 125C