POWER LOSS (mW) LTC3455/LTC3455-1 Dual DC/DC Converter with USB Power Manager and Li-Ion Battery Charger FEATURES DESCRIPTION n Seamless Transition between Input Power Sources: The LTC 3455/LTC3455-1 are complete power manage- Li-Ion Battery, USB, and 5V Wall Adapter ment solutions for a variety of portable applications. n Accurate USB Current Limiting (500mA/100mA) These devices contain two synchronous step-down n Two High Ef ciency DC/DC Converters: Up to 96% DC/DC converters, a USB power controller, a full-featured n Thermal Regulation Maximizes Battery Charge Li-Ion battery charger, a Hot Swap output, a low-battery Rate without Risk of Overheating indicator, and numerous internal protection features. The n Full-Featured Li-Ion Battery Charger with 4.2V Float LTC3455/LTC3455-1 provide a small, simple solution for Voltage for LTC3455 and 4.1V for LTC3455-1 obtaining power from three different power sources: a n 4.1V Float Voltage (LTC3455-1) Improves Battery Life single-cell Li-Ion battery, a USB port, and a wall adapter. and High Temperature Safety Margin Current drawn from the USB bus is accurately limited n Hot Swap Output for SDIO and Memory Cards under all conditions. Whenever a USB or a wall adapter n Pin-Selectable Burst Mode Operation is present, the battery charger is enabled and all internal n Output Disconnect: All Outputs Discharged to Ground power for the device is drawn from the appropriate external During Shutdown power source. All outputs are discharged to ground during n Available in a 4mm 4mm 0.75mm 24-Pin shutdown to provide complete output disconnect. These QFN Package devices are available in a 4mm 4mm 24-pin exposed- pad QFN package. APPLICATIONS L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6522118. n Handheld Computers n Digital Cameras n MP3 Players TYPICAL APPLICATION MODE USB 5V USB 1 SUSPEND HSON USB 5.6V ON2 4.7F CONTROLLER C USBHP PWRON Ef ciency RST WALL 5V V MAX 100 1000 PBSTAT SWITCHER 2 10F 1 V = 3.3V 95 OUT2 1M 4.7F 1M 3.32k LTC3455/LTC3455-1 1k 1.8V 90 ON/OFF CHRG SWITCHER 1 85 100 ON V = 1.8V WALLFB OUT1 0.1F 80 HSO 3.3V, HS 1.24k 1F TIMER 75 PROG 70 10 HSI 2.49k POWER LOSS FOR 4.7H BOTH OUTPUTS 65 3.3V SW2 V BAT 0.5A 10pF 249k 60 4.7F V = 3.6V SINGLE 1.8V BAT FB2 10F + 55 1 CELL Li-ION 1M 1 10 100 1000 3.3V TO 4.2V 80.6k LOAD CURRENT (mA) LBO AO 3455 TA01b 4.7H V BAT SW1 1.8V 0.4A 2.49M 10pF 100k AI 10F FB1 806k 80.6k GND 3455 TA01a 3455fc 1 EFFICIENCY (%)LTC3455/LTC3455-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW Transient (t < 1ms and Duty Cycle < 1%): V USB Voltages .................................. 0.3V to 7V MAX Steady State: 24 23 22 21 20 19 V , V , USB Voltages ........................ 0.3V to 6V BAT MAX FB1 1 18 FB2 SW1, SW2 Voltages ................... 0.3V to (V + 0.3V) MAX PROG AO 2 17 TIMER Voltage ........................... 0.3V to (V + 0.3V) TIMER 3 16 AI MAX 25 CHRG 4 15 HSON PWRON, ON, ON2, HSON Voltages ............. 0.3V to 6V USBHP 5 14 HSO PBSTAT, RST, CHRG, AO Voltages ............... 0.3V to 6V SUSPEND 6 13 HSI HSI, HSO Voltages ....................................... 0.3V to 6V 7 8 9 10 11 12 MODE, USBHP, SUSPEND Voltages.............. 0.3V to 6V WALLFB, AI, PROG Voltages ........................ 0.3V to 2V FB1, FB2 Voltages ........................................ 0.3V to 2V UF PACKAGE Junction Temperature ........................................... 125C 24-LEAD (4mm s 4mm) PLASTIC QFN T = 125C, = 37C/W, = 4.3C/W JMAX JA JC Operating Temperature Range (Note 2)....40C to 85C EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range- .................65C to 125C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3455EUF PBF LTC3455EUF TRPBF 3455 40C to 85C 24-Lead (4mm 4mm) Plastic QFN LTC3455EUF-1 PBF LTC3455EUF-1 TRPBF 34551 40C to 85C 24-Lead (4mm 4mm) Plastic QFN Consult LTC Marketing for parts speci ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: