POWER LOSS (mW) LTC4081 500mA Li-Ion Charger with NTC Input and 300mA Synchronous Buck FEATURES DESCRIPTION Battery Charger: The LTC 4081 is a complete constant-current/constant- n Constant-Current/Constant-Voltage Operation voltage linear battery charger for a single-cell 4.2V with Thermal Feedback to Maximize Charge Rate lithium-ion/polymer battery with an integrated 300mA withoutRisk of Overheating synchronous buck converter. A 3mm 3mm DFN pack- n Internal 4.5-Hour Safety Timer for Termination age and low external component count make the LTC4081 n Charge Current Programmable Up to 500mA with especially suitable for portable applications. Furthermore, 5% Accuracy the LTC4081 is specifically designed to work within USB n NTC Thermistor Input for Temperature Qualified power specifications. Charging The CHRG pin indicates when charge current has dropped n C/10 Charge Current Detection Output to ten percent of its programmed value (C/10). An internal n 5A Supply Current in Shutdown Mode 4.5-hour timer terminates the charge cycle. The full- Switching Regulator: featured LTC4081 battery charger also includes trickle n High Efficiency Synchronous Buck Converter charge, automatic recharge, soft-start (to limit inrush n 300mA Output Current (Constant-Frequency Mode) current) and an NTC thermistor input used to monitor n 2.7V to 4.5V Input Range (Powered from BAT Pin) battery temperature. n 0.8V to V Output Range BAT The LTC4081 integrates a synchronous buck converter n MODE Pin Selects Fixed (2.25MHz) Constant-Frequency that is powered from the BAT pin. It has an adjustable PWM Mode or Low I (23A) Burst Mode Operation CC output voltage and can deliver up to 300mA of load cur- n 2A BAT Current in Shutdown Mode rent. The buck converter also features low current high n 10-Lead, Low Profile (0.75 mm) 3mm 3mm DFN Package efficiency Burst Mode operation that can be selected by the MODE pin. APPLICATIONS The LTC4081 is available in a 10-lead, low profile (0.75mm) n Wireless Headsets 3mm 3mm DFN package. n Bluetooth Applications L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks n and ThinSOT and PowerPath are trademarks of Linear Technology Corporation. All other Portable MP3 Players trademarks are the property of their respective owners. Protected by U.S. Patents, including n Multifunction Wristwatches 6522118. Buck Efficiency vs Load Current TYPICAL APPLICATION (V = 1.8V) OUT Li-Ion Battery Charger with 1.8V Buck Regulator 100 1000 510 EFFICIENCY 80 100 V (Burst) CC EFFICIENCY (3.75V V CHRG 500mA CC (PWM) POWER TO 5.5V) BAT LOSS 4.2V 60 10 + 100k Li-Ion/ (PWM) 4.7F EN BUCK POLYMER 1OH LTC4081 BATTERY NTC 40 1 SW POWER LOSS (Burst) 4.7F 10pF 1M EN CHRG V = 3.8V BAT V OUT 20 0.1 FB V = 1.8V OUT (1.8V/300mA) MODE GND PROG L = 10H 100k T 806k C = 4.7F 806 4.7F 0 0.01 0.01 0.1 1 10 100 1000 4081 TA01a LOAD CURRENT (mA) 4081 TA01b 4081fa 1 For more information www.linear.com/LTC4081 EFFICIENCY (%)LTC4081 (Note 1) ABSOLUTE MAXIMUM RATINGS V , t < 1ms and Duty Cycle < 1% ............... 0.3V to 7V BAT Short-Circuit Duration ...........................Continuous CC V Steady State .......................................... 0.3V to 6V BAT Pin Current .................................................. 800mA CC BAT, CHRG ................................................... 0.3V to 6V PROG Pin Current ....................................................2mA EN CHRG, PROG, NTC ....................0.3V to V + 0.3V Junction Temperature ............................................125C CC MODE, EN BUCK ...........................0.3V to V + 0.3V Operating Temperature Range (Note 2)....40C to 85C BAT FB ................................................................ 0.3V to 2V Storage Temperature Range .................. 65C to 125C PIN CONFIGURATION TOP VIEW BAT 10 SW 1 V 2 9 EN BUCK CC 11 EN CHRG 3 8 MODE PROG 4 7 FB NTC 5 6 CHRG DD PACKAGE 10-LEAD (3mm 3mm) PLASTIC DFN T = 110C, = 43C/W (NOTE 3) JMAX JA EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC4081EDD PBF LTC4081EDD TRPBF LDBX 10-Lead (3mm 3mm) DFN 0C to 70C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: