LTC3556 High Efficiency USB Power Manager with Dual Buck and Buck-Boost DC/DCs FEATURES DESCRIPTION POWER MANAGER The LTC 3556 is a highly integrated power management TM n High Efficiency Switching PowerPath Controller and battery charger IC for Li-Ion/Polymer battery applica- TM with Bat-Track Adaptive Output Control tions. It includes a high efficiency current limited switch- n Programmable USB or Wall Current Limit ing PowerPath manager with automatic load prioritization, (100mA/500mA/1A) a battery charger, an ideal diode, and three synchronous n Full Featured Li-Ion/Polymer Battery Charger switching regulators (two bucks and one buck-boost). n Instant-On Operation with a Discharged Battery Designed specically for USB applications, the LTC3556s n 1.5A Maximum Charge Current switching power manager automatically limits input cur- n Internal 180m Ideal Diode Plus External Ideal Diode rent to a maximum of either 100mA or 500mA for USB Controller Powers Load in Battery Mode applications or 1A for adapter-powered applications. n Low No-Load I when Powered from BAT (<30A) Q The LTC3556s switching input stage transmits nearly all DC/DCs of the 2.5W available from the USB port to the system n Dual High Efficiency Buck DC/DCs (400mA/400mA I ) OUT load with minimal power wasted as heat. This feature n High Efficiency Buck-Boost DC/DC (1A I ) OUT allows the LTC3556 to provide more power to the appli- n All Regulators Operate at 2.25MHz cation and eases the constraint of thermal budgeting in n Dynamic Voltage Scaling on Two Buck Outputs small spaces. The two buck regulators can provide up to 2 n I C Control of Enables, Mode, Two V Settings OUT 400mA each and the buck-boost can deliver 1A. n ENALL Pin with Power-Up Sequence Control The LTC3556 is available in the low profile 28-pin (4mm n Low No-Load Quiescent Current: 20A Each 5mm 0.75mm) QFN surface mount package. All registered trademarks and trademarks are the property of their respective owners. Protected APPLICATIONS by U.S. patents, including 6522118 and 6404251. n HDD-Based MP3 Players, PDAs, GPS, PMPs n Other USB-Based Handheld Products TYPICAL APPLICATION Battery Charge Current High Efficiency PowerPath Manager, Dual Buck, Buck-Boost and LDO vs Battery Voltage USB/WALL TO OTHER USB COMPLIANT 4.5V TO 5.5V LOADS 700 STEP-DOWN BATTERY CHARGE CURRENT REGULATOR 600 EXTRA CURRENT CC/CV FOR FASTER CHARGING 0V OPTIONAL 500 BATTERY 500mA USB CURRENT LIMIT CHARGER 400 CHARGE + Li-Ion 300 T LTC3556 200 3.3V/25mA RTC/LOW ALWAYS ON LDO POWER LOGIC V = 5V BUS 100 5X MODE 0.8V TO 3.6V/400mA 1 MEMORY DUAL HIGH EFFICIENCY BATTERY CHARGER PROGRAMMED FOR 1A ENALL CORE BUCKS 0.8V TO 3.6V/400mA 0 2 P 2.8 3.2 3.4 3.6 3.8 4.2 3 4 HIGH EFFICIENCY BATTERY VOLTAGE (V) SEQ 3 BUCK-BOOST 2.5V to 3.3V/1A 3556 TA01b HDD/IO 3 2 2 I C I C PORT PGOODALL 3556 TA01 Rev. B 1 Document Feedback For more information www.analog.com CHARGE CURRENT (mA)LTC3556 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V (Transient) t < 1ms, Duty Cycle < 1% .. 0.3V to 7V BUS V , V , V , V (Static), DV , IN1 IN2 IN3 BUS CC FB1, FB2, NTC, BAT, SCL, SDA, 28 27 26 25 24 23 PGOODALL, CHRG ....................................... 0.3V to 6V LDO3V3 1 22 GATE CLPROG 2 21 CHRG ENALL ...................................... 0.3V to Lesser of 6V or NTC 3 20 PROG MAX(V , V , BAT) + 0.3V BUS OUT SW1 4 19 SW2 SEQ ................... 0.3V to Lesser of 6V or (V + 0.3V) 29 OUT V 5 18 V IN1 IN2 FB3, V ..............0.3V to Lesser of 6V or (V + 0.3V) C3 IN3 FB1 6 17 FB2 I ....................................................................3mA CLPROG FB3 7 16 SDA I , I ....................................................50mA V 8 15 PGOODALL CHRG PGOODALL C3 I ........................................................................2mA 9 10 11 12 13 14 PROG I ...................................................................30mA LDO3V3 I , I ........................................................... 600mA SW1 SW2 UFD PACKAGE I , I , I ............................................................2A SW BAT VOUT 28-LEAD (4mm 5mm) PLASTIC QFN I , I , I .............................................2.5A T = 125C, = 37C/W JMAX JA SWAB3 SWCD3 VOUT3 EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB Operating Temperature Range (Note 2)....40C to 85C Junction Temperature (Note 3) ............................. 125C Storage Temperature Range .................. 65C to 125C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3556EUFD PBF LTC3556EUFD TRPBF 3556 28-Lead (4mm 5mm) Plastic QFN 40C to 85C Contact the factory for parts specified with wider operating temperature ranges. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. Rev. B 2 For more information www.analog.com SWAB3 ENALL DV SEQ CC V SW IN3 V V OUT3 BUS SCL V OUT SWCD3 BAT