LTC3550-1 Dual Input USB/AC Adapter Li-Ion Battery Charger with 600mA Buck Converter FEATURES DESCRIPTIO Charges Single-Cell Li-Ion Batteries from Wall The LTC 3550-1 is a standalone linear charger with a Adapter and USB Inputs 600mA monolithic synchronous buck converter. It is Automatic Input Power Detection and Selection capable of charging a single-cell Li-Ion battery from both Charge Current Programmable Up to 950mA from wall adapter and USB inputs. The charger automatically Wall Adapter Input selects the appropriate power source for charging. High Ef ciency 600mA Synchronous DC/DC Internal thermal feedback regulates the battery charge Converter current to maintain a constant die temperature during high No External MOSFET, Sense Resistor or Blocking power operation or high ambient temperature conditions. Diode Needed The oat voltage is xed at 4.2V and the charge currents Thermal Regulation Maximizes Charge Rate Without are programmed with external resistors. The LTC3550-1 Risk of Overheating* terminates the charge cycle when the charge current drops Preset Charge Voltage with 0.6% Accuracy below the programmed termination threshold after the Programmable Charge Current Termination nal oat voltage is reached. With power applied to both 1.5MHz Constant Frequency Operation (Step-Down inputs, the LTC3550-1 can be put into shutdown mode Converter) reducing the DCIN supply current to 20A, the USBIN 18A USB Suspend Current in Shutdown supply current to 10A, and the battery drain current to Independent Power Present Status Outputs less than 2A. Charge Status Output The synchronous buck converter generates a xed output Automatic Recharge voltage of 1.875V. The switching frequency is internally Available in a Thermally Enhanced, Low Pro le set at 1.5MHz, allowing the use of small surface mount (0.75mm) 16-Lead (5mm x 3mm) DFN Package inductors and capacitors. U , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO S All other trademarks are the property of their respective owners. *Protected by U.S. patents, includng 6522118, 6700364, 6580258, 5481178, 6304066, 6127815, 6498466, 6611131 Cellular Telephones TYPICAL APPLICATIO Complete Charge Cycle (1100mA Battery) 1000 Dual Input Battery Charger and DC/DC Converter 800 600 400 LTC3550-1 2.2H V OUT 200 1.875V RUN SW 0 WALL CONSTANT VOLTAGE 600mA C 4.2 OUT ADAPTER DCIN V OUT 10F 4.0 800mA (WALL) USBIN V CER USBIN = 5V USB CC 3.8 500mA (USB) T = 25C PORT A 1F 3.6 BAT IUSB R = 1.25k IDC 3.4 2k R = 2k 4.7F IUSB IDC ITERM 1% 5.0 4.2V + 1F GND 2k 1.24k SINGLE-CELL 2.5 1% 1% Li-Ion BATTERY 0 2.5 3550-1 TA01 0 0.5 1.0 1.5 2.0 2.5 3.0 TIME (HR) 3550-1 TA02 35501f 1 DCIN BATTERY CHARGE VOLTAGE (V) VOLTAGE (V) CURRENT (mA) U ULTC3550-1 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW DCIN, USBIN .............................................. 0.3V to 10V USBIN 1 16 DCIN ENABLE, CHRG, PWR, USBPWR ............... 0.3V to 10V IUSB 2 15 BAT BAT, IDC, IUSB, ITERM ................................ 0.3V to 7V ITERM 3 14 IDC V ............................................................... 0.3V to 6V CC PWR 4 13 USBPWR RUN, V ..................................................0.3V to V 17 OUT CC CHRG 5 12 ENABLE SW (DC) ........................................0.3V to (V + 0.3V) CC V 6 11 RUN OUT DCIN Pin Current (Note 2) ..........................................1A V 7 10 SW CC USBIN Pin Current (Note 2) .................................700mA GND 8 9 GND BAT Pin Current (Note 2) ............................................1A DHC PACKAGE P-Channel SW Source Current (DC) .....................800mA 16-LEAD (5mm 3mm) PLASTIC DFN T = 125C, = 40C (Note 4) N-Channel SW Source Current (DC) ....................800mA JMAX JA EXPOSED PAD IS GROUND (PIN 17) Peak SW Sink and Source Current ...........................1.3A MUST BE SOLDERED TO PCB Operating Temperature Range (Note 3) ... 40C to 85C Maximum Junction Temperature .......................... 125C ORDER PART NUMBER PART MARKING Storage Temperature Range ................... 65C to 125C LTC3550EDHC-1 35501 Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: