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LTC3440 Dataheets PDF



Part Number LTC3440
Manufacturers Linear Technology
Logo Linear Technology
Description Buck-Boost DC/DC Converter
Datasheet LTC3440 DatasheetLTC3440 Datasheet (PDF)

LTC3440 Micropower Synchronous Buck-Boost DC/DC Converter Features nn Single Inductor nn Fixed Frequency Operation with Battery Voltages Above, Below or Equal to the Output nn Synchronous Rectification: Up to 96% Efficiency nn 25µA Quiescent Current in Burst Mode® Operation nn Up to 600mA Continuous Output Current nn No Schottky Diodes Required (VOUT < 4.3V) nn VOUT Disconnected from VIN During Shutdown nn 2.5V to 5.5V Input and Output Range nn Programmable Oscillator Frequency from 300kHz to 2.

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LTC3440 Micropower Synchronous Buck-Boost DC/DC Converter Features nn Single Inductor nn Fixed Frequency Operation with Battery Voltages Above, Below or Equal to the Output nn Synchronous Rectification: Up to 96% Efficiency nn 25µA Quiescent Current in Burst Mode® Operation nn Up to 600mA Continuous Output Current nn No Schottky Diodes Required (VOUT < 4.3V) nn VOUT Disconnected from VIN During Shutdown nn 2.5V to 5.5V Input and Output Range nn Programmable Oscillator Frequency from 300kHz to 2MHz nn Synchronizable Oscillator nn Burst Mode Enable Control nn <1µA Shutdown Current nn Small Thermally Enhanced 10-Pin MSOP and (3mm × 3mm) DFN Packages Applications nn Palmtop Computers nn Handheld Instruments nn MP3 Players nn Digital Cameras Description The LTC®3440 is a high efficiency, fixed frequency, BuckBoost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The topology incorporated in the IC provides a continuous transfer function through all operating modes, making the product ideal for single lithium-ion, multicell alkaline or NiMH applications where the output voltage is within the battery voltage range. The device includes two 0.19Ω N-channel MOSFET switches and two 0.22Ω P-channel switches. Switching frequencies up to 2MHz are programmed with an external resistor and the oscillator can be synchronized to an external clock. Quiescent current is only 25µA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin has either a clock or is driven low, then fixed frequency switching is enabled. Other features include a 1µA shutdown, soft-start control, thermal shutdown and current limit. The LTC3440 is available in the 10-pin thermally enhanced MSOP and (3mm × 3mm) DFN packages. L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Li-Ion to 3.3V at 600mA Buck-Boost Converter L1 10µH 3 SW1 4 SW2 VIN = 2.7V TO 4.2V 7 LTC3440 6 VIN VOUT R1 340k + Li-Ion 8 SHDN/SS 9 FB C5 1.5nF 2 10 C1 * MODE/SYNC VC 10µF 1 RT 5 GND RT R3 15k R2 200k 60.4k VOUT 3.3V 600mA C2 22µF *1 = Burst Mode OPERATION 0 = FIXED FREQUENCY C1: TAIYO YUDEN JMK212BJ106MG C2: TAIYO YUDEN JMK325BJ226MM L1: SUMIDA CDRH6D38-100 3440 TA01 EFFICIENCY (%) Efficiency vs V­IN 100 98 VOUT = 3.3V IOUT = 100mA 96 fOSC = 1MHz 94 92 90 88 86 84 82 80 2.5 3.0 3.5 4.0 4.5 VIN (V) 5.0 5.5 3440 TA02 For more information www.linear.com/LTC3440 3440fd 1 LTC3440 Absolute Maximum Ratings (Note 1) VIN, VOUT Voltage ........................................ – 0.3V to 6V SW1, SW2 Voltage....................................... –0.3V to 6V VC, RT, FB, SHDN/SS, MODE/SYNC Voltage................................... –0.3V to 6V Operating Temperature Range (Note 2)....–40°C to 85°C Storage Temperature Range................... –65°C to 125°C Lead Temperature (Soldering, 10 sec).................... 300°C Pin Configuration TOP VIEW RT 1 MODE/SYNC 2 10 VC 9 FB SW1 3 11 8 SHDN/SS SW2 4 GND 5 7 VIN 6 VOUT DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN EXPOSED PAD (PIN 11) IS GND MUST BE SOLDERED TO PCB TJMAX = 125°C, θJA = 43°C/W, θJC = 3°C/W TOP VIEW RT 1 MODE/SYNC 2 SW1 3 SW2 4 GND 5 10 VC 9 FB 8 SHDN/SS 7 VIN 6 VOUT MS PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 130°C/W 1 layer board θJA = 100°C/W 4 layer board θJC = 45°C/W Order Information http://www.linear.com/product/LTC3440#orderinfo LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LTC3440EDD#PBF LTC3440EDD#TRPBF LBKT 10-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C LTC3440EMS#PBF LTC3440EMS#TRPBF LTNP 10-Lead Plastic MSOP –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on nonstandard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. Electrical Characteristics The ● denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = VOUT = 3.6V, RT = 60k, unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Input Start-Up Voltage l 2.4 2.5 V Input Operating Range l 2.5 5.5 V Output Voltage Adjust Range l 2.5 5.5 V Feedback Voltage l 1.196 1.22 1.244 V Feedback Input Current Quiescent Current, Burst Mode Operation Quiescent Current, Shutdown VFB = 1.22V VC = 0V, MODE/SYNC = .


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