POWER LOSS (mW) LTC3552 Standalone Linear Li-Ion Battery Charger and Dual Synchronous Buck Converter FEATURES DESCRIPTIO Programmable Charge Current Up to 950mA The LTC 3552 is a complete constant-current/constant- Complete Linear Charger and Dual DC/DC voltage linear charger with a dual DC/DC converter for Regulator single cell lithium-ion batteries. Its DFN package and low Buck Converter Output Voltage from 0.6V to 5V external component count make the LTC3552 ideally suited No MOSFET, Sense Resistor or Blocking Diode for portable applications. Furthermore, the LTC3552 is Required designed to work within USB power speci cations. Thermal Regulation Maximizes Charge Rate No external sense resistor or external blocking diode is Without Risk of Overheating* required due to the internal MOSFET architecture. The Charges Directly from a USB Port charge voltage is xed at 4.2V and the charge current is Programmable Charge Current Termination programmed with a resistor. The charge cycle terminates Preset 4.2V Charge Voltage with 1% Accuracy when the charge current drops below the programmed Charge Current Monitor Output for Gas Gauging* termination threshold after the nal oat voltage is reached. Automatic Recharge When the input supply (wall adapter or USB supply) is Charge Status Output removed, the LTC3552 enters a low current state dropping Power Present Output the battery drain current to less than 2A. Thermal regula- 2.9V Trickle Charge Threshold tion maximizes charge rate without risk of overheating. Soft-Start Limits Inrush Current The synchronous step-down switching regulators gen- Low Quiescent Current Buck Converter (40A) erate adjustable output voltages from 5V down to 0.6V. Current Mode Operation, Constant Frequency (2.25MHz) The switching frequency is set at 2.25MHz, allowing the Low Pro le (5mm 3mm 0.75mm) DFN Package use of small surface mount inductors and capacitors. U APPLICATIO S , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Protected by U.S. patents, including 6522118, 6700364, 5481178, 6580258, 6304066, Cellular Telephones, PDAs, MP3 Players 6127815, 6498466, 6611131. Bluetooth Applications TYPICAL APPLICATIO Ef ciency Curve/ Power Loss of Regulators Single Cell Li-Ion Battery Charger with 100 1000 C/5 Termination and Dual DC/DC Converter 95 LTC3552 90 100 EFFICIENCY V V RUN1 IN IN 4.5V TO 1F 800mA RUN2 85 6.5V ITERM 4.2V + 1-CELL 619 BAT PROG 10F 80 10 Li-Ion POWER LOSS 1.24k BATTERY CHRG V CC 75 PWR POR 70 1 EN MODE/SYNC 4.7H 2.2H V V OUT2 OUT1 2.5V/ SW2 SW1 1.8V/ 65 400mA 800mA C C OUT2 C R4 R2 C OUT1 FF2 FF1 60 0.1 4.7F 10F 1 10 100 1000 68pF 887k 604k 33pF CER V V CER FB2 FB1 LOAD CURRENT (mA) GND 3552 TA01b R3 R1 V = 3.3V, V = 1.8V CC OUT 280k 301k Burst Mode OPERATION 3552 TA01 REGULATOR 1, NO LOAD ON REGULATOR 2 3552f 1 EFFICIENCY (%) U ULTC3552 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW Charger Input Supply (V ) ........................ 0.3V to 10V IN ITERM 1 16 EN PROG, ITERM .................................. 0.3V to V + 0.3V IN BAT 2 15 PWR BAT .............................................................. 0.3V to 7V CHRG 3 14 V IN CHRG, PWR, EN ......................................... 0.3V to 10V MODE/SYNC 4 13 PROG BAT Short-Circuit Duration ............................Continuous 17 SW2 5 12 SW1 BAT Pin Current ..........................................................1A POR 6 11 V CC PROG Pin Current ....................................................1mA RUN2 7 10 RUN1 Converter Input Supply (V ) ....................... 0.3V to 6V CC V 8 9 V FB2 FB1 V , V , RUN1, RUN2 ...................0.3V to V +0.3V FB1 FB2 CC DHC PACKAGE MODE/SYNC ....................................0.3V to V + 0.3V CC 16-LEAD (5mm 3mm) PLASTIC DFN SW1, SW2 .......................................0.3V to V + 0.3V T = 125C, = 40C/W (Note 3) CC JMAX JA EXPOSED PAD IS GROUND (PIN 17) POR ............................................................. 0.3V to 6V MUST BE SOLDERED TO PCB Ambient Operating Temperature ORDER PART NUMBER DHC PART MARKING Range (Note 2) .................................... 40C to 85C Maximum Junction Temperature (Note 8) ............ 125C LTC3552EDHC 3552 Storage Temperature Range ................... 65C to 125C Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: