POWER LOSS (W) LTC3429/LTC3429B 600mA, 500kHz Micropower Synchronous Boost Converter with Output Disconnect FEATURES DESCRIPTIO Up to 96% Efficiency The LTC 3429/LTC3429B are high efficiency synchro- True Output Load Disconnect nous, fixed frequency, step-up DC/DC converters with true Inrush Current Limiting and Internal Soft-Start output load disconnect, inrush current limiting and soft- TM Low Voltage Start-Up: 0.85V start in a low profile 6-lead ThinSOT package. These Automatic Burst Mode Operation with I ~ 20A devices are capable of supplying 100mA from a single AA Q Continuous Switching at Light Loads (LTC3429B) cell input or 250mA from a 2-cell AA with a 3.3V output. Internal Synchronous Rectifier A switching frequency of 500kHz minimizes overall solu- Current Mode Control with Internal Compensation tion footprint by allowing the use of tiny, low profile Short-Circuit Protection inductors and ceramic capacitors. Current mode PWM 500kHz Fixed Frequency Switching control with internal compensation reduces external parts Input Range: 0.5V to 4.4V count thereby saving critical board real estate. The LTC3429 Output Range: 2.5V to 4.3V (Up to 5V with Schottky) shifts automatically to power saving Burst Mode operation Shutdown Current: <1A at light loads while the LTC3429B features continuous Antiringing Control Minimizes EMI switching at light loads. Antiringing control circuitry re- Tiny External Components duces EMI concerns by damping the inductor in discon- Low Profile (1mm) SOT-23 Package tinuous mode. U The devices also feature low shutdown current of under APPLICATIO S 1A. The true output disconnect feature allows the output MP3 Players to be completely discharged in shutdown. It also limits the Digital Cameras inrush of current during start-up, minimizing surge cur- LCD Bias Supplies rents seen by the input supply. Handheld Instruments , LTC and LT are registered trademarks of Linear Technology Corporation. All other Wireless Handsets trademarks are the property of their respective owners. Burst Mode is a registered trademark of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology GPS Receivers Corporation. TYPICAL APPLICATIO 2-Cell to 3.3V Efficiency 100 100 V = 3V IN 4.7H 90 10 EFFICIENCY + 2-CELL V = 2.4V IN 4.7F SW 80 1 AA V OUT 3.3V V V IN OUT 250mA 70 V = 2.4V 0.1 LTC3429 1.02M IN OFF ON SHDN FB 10F V = 3V IN 60 0.01 GND 604k POWER LOSS 50 0.001 3429 F01a 40 0.0001 0.1 1 10 100 1000 Figure 1. 2-Cell to 3.3V Synchronous Boost Converter OUTPUT CURRENT (mA) 3429 F01b 3429fa 1 EFFICIENCY (%) U ULTC3429/LTC3429B UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART V Voltage .............................................. 0.3V to 4.4V IN TOP VIEW NUMBER SW Voltage ................................................. 0.3V to 6V SW 1 6 V IN SHDN, FB Voltage ....................................... 0.3V to 6V LTC3429ES6 GND 2 5 V OUT V ........................................................... 0.3V to 6V LTC3429BES6 OUT FB 3 4 SHDN Operating Temperature Range (Note 2) .. 40C to 85C S6 PACKAGE S6 PART MARKING Storage Temperature Range ................... 65C to 150 6-LEAD PLASTIC TSOT-23 LTH5 Lead Temperature (Soldering, 10 sec).................. 300C T = 125C, = 102C/W JMAX JC LTBMS Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. V = 1.2V, V = 3.3V, unless otherwise specified. A IN OUT PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Start-Up Voltage I = 1mA, V = 0V 0.85 1 V LOAD OUT Minimum Operating Voltage SHDN = V (Note 3) 0.5 0.65 V IN Output Voltage Adjust Range (Note 5) 2.5 5 V Feedback Voltage 1.192 1.230 1.268 V Feedback Input Current V = 1.25V 1 50 nA FB Quiescent Current (Burst Mode Operation) V = 1.4V (Note 4) 20 30 A FB Quiescent Current (Shutdown) V = 0V, Not Including Switch Leakage, V = 0V 0.01 1 A SHDN OUT Quiescent Current (Active) Measured on V , Nonswitching 380 550 A OUT NMOS Switch Leakage V = 5V 0.1 5 A SW PMOS Switch Leakage V = 5V, V = 0V 0.1 5 A SW OUT NMOS Switch On Resistance 0.35 PMOS Switch On Resistance 0.45 NMOS Current Limit 600 850 mA Burst Mode Operation Current Threshold L = 4.7H (LTC3429 Only) 1.25 mA Current Limit Delay to Output 40 ns Max Duty Cycle V = 1.15V 80 90 % FB Switching Frequency 380 500 620 kHz SHDN Input High 1V SHDN Input Low 0.35 V SHDN Input Current V = 5.5V 0.01 1 A SHDN Soft-Start Time SHDN to 90% of V 2.5 ms OUT Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: Minimum V operation after start-up is only limited by the IN of a device may be impaired. batterys ability to provide the necessary power as it enters a deeply discharged state. Note 2: The LTC3429ES6/LTC3429BES6 are guaranteed to meet performance specifications from 0C to 70C. Specifications over the Note 4: Burst Mode operation I is measured at V . Multiply this value Q OUT 40C to 85C operating temperature range are assured by design, by V /V to get the equivalent input (battery) current. OUT IN characterization and correlation with statistical process controls. Note 5: For applications where V > 4.3V, an external Schottky diode is OUT required. See the Applications Information. 3429fa 2 U WWW