LTC3499/LTC3499B 750mA Synchronous Step-Up DC/DC Converters with Reverse-Battery Protection FEATURES DESCRIPTION n Reverse-Battery Protection for DC/DC Converter The LTC 3499/LTC3499B are synchronous, fixed frequency and Load step-up DC/DC power converters with integrated reverse n High Efficiency: Up to 94% battery protection that protect and disconnect the devices n Generates 5V at 175mA from a 1.8V Input and load when the battery polarity is reversed while n Operates from 1.8V to 5.5V Input Supply delivering high efficiency in a small (3mm 3mm) DFN n 2V to 6V Adjustable Output Voltage package. True output disconnect eliminates inrush current n Inrush Current Controlled During Start-Up and allows zero load current in shutdown. n Output Disconnnect in Shutdown The devices feature an input voltage range of 1.8V to 5.5V n Low Noise 1.2MHz PWM Operation enabling operation from two alkaline or NiMH batteries. The n Tiny External Components switching frequency is internally set at 1.2MHz allowing n Automatic Burst Mode Operation (LTC3499) the use of tiny surface mount inductors and capacitors. n Continuous Switching at Light Loads (LTC3499B) A minimal number of external components are required n Overvoltage Protection to generate output voltages ranging from 2V to 6V. The n 8-Lead (3mm 3mm 0.75mm) DFN LTC3499 features automatic Burst Mode operation to and MSOP Packages increase efficiency at light loads, while the LTC3499B features continuous switching at light loads. APPLICATIONS The soft-start time is externally programmable through a n Medical Equipment small capacitor. Anti-ring circuitry reduces EMI emissions n Digital Cameras by damping the inductor in discontinuous mode. The de- n MP3 Players vices feature <1A shutdown supply current, integrated n Handheld Instruments overvoltage protection and are available in both 8-pin (3mm 3mm) DFN and 8-pin MSOP packages. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION Two AA Cells to 5V Synchronous Boost Converter Battery Current vs V IN 1.0 4.7H SHDN = 0V V IN V = 0V OUT 1.8V TO 3.2V + 2.2F V SW IN 0.5 LTC3499 V OUT V OUT 5V ON OFF SHDN 0 175mA 1M VC 10F FB 100k SS 0.5 GND 324k 330pF 0.01F 1.0 3499 TA01 6 4 2 0 2 4 6 V AND SW VOLTAGE (V) IN 3499 TA01b 3499fc 1 BATTERY CURRENT (A)LTC3499/LTC3499B (Note 1) ABSOLUTE MAXIMUM RATINGS V to GND ..................................................... 7V to 7V FB, SS to GND ............................................. 0.3V to 7V IN V to GND .............................................. 0.3V to 7V Operating Temperature Range OUT SW to V ................................................... 7V to 1V (Notes 3, 4) ......................................... 40C to 85C OUT SW to GND Storage Temperature Range ................. 65C to 125C DC ............................................................... 7V to 7V Lead Temperature (Soldering, 10 sec) Pulsed < 100ns ........................................... 7V to 8V MSOP .............................................................. 300C SHDN to GND ................................................. 7V to 7V PIN CONFIGURATION TOP VIEW TOP VIEW SHDN 1 8 VC SHDN 1 8 VC V 2 7 FB IN 9 V 2 7 FB IN SW 3 6 V OUT SW 6 3 V OUT GND 4 5 SS GND SS 4 5 MS8 PACKAGE 8-LEAD PLASTIC MSOP DD PACKAGE T = 125C, = 160C/W JMAX JA 8-LEAD (3mm 3mm) PLASTIC DFN T = 125C, = 45C JMAX JA EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3499EDD PBF LTC3499EDD TRPBF LBRB 8-Lead (3mm 3mm) Plastic DFN 40C to 85C LTC3499BEDD PBF LTC3499BEDD TRPBF LCDZ 40C to 85C 8-Lead (3mm 3mm) Plastic DFN LTC3499EMS8 PBF LTC3499EMS8 TRPBF LTBRC 8-Lead Plastic MSOP 40C to 85C LTC3499BEMS8 PBF LTC3499BEMS8 TRPBF LTCFB 8-Lead Plastic MSOP 40C to 85C 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: