LTC3423/LTC3424 Low Output Voltage, 3MHz Micropower Synchronous Boost Converters FEATURES DESCRIPTIO n 1.5V to 5.5V Adjustable Output Voltage The LTC 3423 and LTC3424 are high efficiency, fixed n Synchronous Rectification: Up to 95% Efficiency frequency, step-up DC/DC converters that can regulate n 1A Switch Current (LTC3423) or output voltages as low as 1.5V from a single cell. An 2A Switch Current (LTC3424) applied voltage of at least 2.7V to the V pin is required DD n Fixed Frequency Operation Up to 3MHz to power the internal control circuitry. n Wide Input Range: 0.5V to 5.5V (Operating) The devices include a 0.16W N-channel MOSFET switch n Very Low Quiescent Current: 38m A (Burst Mode and a 0.21W P-channel synchronous rectifier. The LTC3423 Operation) is intended for applications requiring less than 0.75W of n No External Schottky Diode Required output power and the LTC3424 for 1.5W or less. Switching n Synchronizable Switching Frequency frequencies up to 3MHz are programmed with an external n Burst Mode Enable Control timing resistor and the oscillator can be synchronized to n OPTI-LOOP Compensation an external clock. n Very Low Shutdown Current: <1m A n Quiescent current is only 38m A in Burst Mode operation, Small 10-Pin MSOP Package maximizing battery life in portable applications. Burst U APPLICATIO S Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin n Pagers has either a clock or is driven low then the operation is at n Handheld Instruments constant fixed frequency. n Cordless Phones n Wireless Handsets Other features include a 1m A shutdown, thermal shutdown n GPS Receivers and current limit. The LTC3423 and LTC3424 are available n Battery Backup in the 10-lead MSOP package. For applications requiring an output voltage greater than 2.6V, the LTC3401 and , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation. LTC3402 are recommended without the need of a separate voltage for the V pin. DD TYPICAL APPLICATIO 1-Cell to 1.8V at 600mA Step-Up Converter V = 2.7V TO 5.5V DD L1 Efficiency V DD 2.2H V V = 0.9V TO 1.5V OUT IN 1.8V 100 V = 1.5V 600mA IN 90 LTC3424 Burst Mode 6 4 R1 V SW 80 OPERATION DD 110k V = 1.2V IN 10 7 70 V = 0.9V SHDN V IN OUT + 1 C3 60 3 8 CELL V FB 44F IN 50 (2 22F) 2 9 MODE/SYNC V 40 C C4 C1 C2 1 5 30 470pF R2 2.2F 10F R GND t 249k C5 20 V = 3.3V DD 4.7pF R RC t V = 1.8V 10 OUT 30.1k 82k WITH MBRM120T3 SCHOTTKY 0 0.1 1 10 100 1000 C1: TAIYO YUDEN JMK212BJ225MG OUTPUT CURRENT (mA) 0 = FIXED FREQ C2: TAIYO YUDEN JMK212BJ106MM 3223/24 TA02 C3: TAIYO YUDEN JMK325BJ226MM 1 = Burst Mode OPERATION L1: SUMIDA CD43-2R2M 3423/24 TA01 34234f 1 EFFICIENCY (%) U ULTC3423/LTC3424 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) V , V , V Voltages.............................. 0.5V to 6V ORDER PART IN OUT DD TOP VIEW SW Voltage ................................................. 0.5V to 6V NUMBER R 1 10 SHDN t V , R Voltages ......................... 0.5V to (V + 0.3V) C t OUT MODE 2 9 V C LTC3423EMS V 3 8 FB SHDN, FB, MODE Voltages ......................... 0.5V to 6V IN SW 4 7 V OUT LTC3424EMS Operating Temperature Range (Note 2) .. 40 C to 85 C GND 5 6 V DD Storage Temperature Range ................. 65 C to 125 C MS PACKAGE MS PART MARKING 10-LEAD PLASTIC MSOP Lead Temperature (Soldering, 10 sec).................. 300 C T = 125 C JMAX q = 130 C/ W 1 LAYER BOARD LTQM JA q = 100 C/ W 4 LAYER BOARD JA LTQN Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at T = 25 C. A V = 1.2V, V = 3.3V, V = 1.8V, unless otherwise noted. IN DD OUT PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Voltage Range l 2.7 5.5 V DD V Operating Voltage Range (Note 4) l 0.5 5.5 V IN Output Voltage Adjust Range l 1.5 5.5 V Feedback Voltage l 1.22 1.25 1.28 V Feedback Input Current V = 1.25V 1 50 nA FB Quiescent CurrentBurst Mode Operation V = 0V, MODE/SYNC = 3.3V (Note 3) 38 65 m A C Quiescent CurrentSHDN SHDN = 0V, Not Including Switch Leakage 0.1 1 m A Quiescent CurrentActive V = 0V, MODE/SYNC = 0V, R = 300k (Note 3) 440 800 m A C t NMOS Switch Leakage 0.1 5 m A PMOS Switch Leakage 0.1 10 m A NMOS Switch On Resistance 0.16 W PMOS Switch On Resistance 0.21 W NMOS Current Limit LTC3423 l 1 1.6 A LTC3424 l 2 2.8 A Maximum Duty Cycle R = 15k l 80 85 % t Minimum Duty Cycle l 0% Frequency Accuracy R = 15k l 1.6 2 2.4 MHz t MODE/SYNC Input High 1.4 V MODE/SYNC Input Low 0.4 V MODE/SYNC Input Current V = 5.5V 0.01 1 m A MODE/SYNC Error Amp Transconductance D I = 5m A to 5m A, V = V 85 m mhos C FB 34234f 2 U WWW