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LTC3458 Dataheets PDF



Part Number LTC3458
Manufacturers Linear Technology
Logo Linear Technology
Description 1.5MHz Synchronous Step-Up DC/DC Converter
Datasheet LTC3458 DatasheetLTC3458 Datasheet (PDF)

U U FEATURES ■ High Efficiency: Up to 93% ■ Inrush Current Limiting and Output Disconnect ■ Programmable Output Voltages up to 7.5V ■ 1.5V to 6V Input Range ■ Programmable/Synchronizable Fixed Frequency Operation up to 1.5MHz ■ Programmable Automatic Burst Mode® Operation ■ Current Mode Control with Programmable Soft-Start Period and Peak Current Limit ■ 700mA at 7V from 5V Input ■ 0.3Ω N-Channel and 0.4Ω P-Channel 1.4A Switches at 5VOUT ■ Ultralow Quiescent Currents: 15μA Sleep, <1μA in Shutdo.

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U U FEATURES ■ High Efficiency: Up to 93% ■ Inrush Current Limiting and Output Disconnect ■ Programmable Output Voltages up to 7.5V ■ 1.5V to 6V Input Range ■ Programmable/Synchronizable Fixed Frequency Operation up to 1.5MHz ■ Programmable Automatic Burst Mode® Operation ■ Current Mode Control with Programmable Soft-Start Period and Peak Current Limit ■ 700mA at 7V from 5V Input ■ 0.3Ω N-Channel and 0.4Ω P-Channel 1.4A Switches at 5VOUT ■ Ultralow Quiescent Currents: 15μA Sleep, <1μA in Shutdown ■ 3mm × 4mm Thermally Enhanced DFN Package U APPLICATIO S ■ Point-of-Load Regulators ■ USB VBUS Power ■ LCD Bias ■ OLED Displays LTC3458 1.4A, 1.5MHz Synchronous Step-Up DC/DC Converter with Output Disconnect DESCRIPTIO The LTC®3458 is a high efficiency, current mode, fixed frequency, step up DC/DC converter with true output disconnect and inrush current limiting. The LTC3458 is rated for a 7.5V output and includes a 0.3Ω N-channel MOSFET switch and a 0.4Ω P-channel MOSFET synchronous rectifier. The LTC3458 is well suited for battery powered applications and includes programmable output voltage, switching frequency and loop compensation. The oscillator frequency can be set up to 1.5MHz or synchronized to an external clock. Quiescent current is only 15μA during Burst Mode operation maximizing battery life in portable applications. The Burst Mode current threshold, peak current limit, and softstart are externally programmable. Other features include <1μA shutdown current, antiringing control, and thermal limit. The LTC3458 is available in a low profile (0.75mm), 3mm × 4mm 12-pin DFN package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Burst Mode is a registered trademark of Linear Technology Corporation. TYPICAL APPLICATIO USB to 7V at 1MHz COEV 10μH DQ7545 USB 4.35V to 5.25V 2.2μF VIN SW LTC3458 GND/PGND VOUT ON OFF SHDN FB SYNC RT ILIM 200k 124k COMP 0.01μF SS BURST 0.01μF 133k 10pF 1.5M VOUT 7V 500mA 33k 10pF 560pF 316k 22μF X5R 3458 TA01a EFFICIENCY POWER LOSS (mW) USB to 7VOUT 100 1000 95 5.25VIN 90 4.35VIN 85 10 POWER LOSS 80 75 70 0.1 1 10 100 LOAD CURRENT (mA) 0.1 1000 3458 TA01b 3458fa 1 LTC3458 U WW W ABSOLUTE AXI U RATI GS (Note 1) VIN, SS, SYNC Voltages ................................. –0.3 to 7V BURST, SHDN, VOUT Voltages ....................... –0.3 to 8V Operating Temperature Range (Notes 2, 3) .........................................–40°C to 85°C Storage Temperature Range ..................–65°C to 125°C SW Voltage DC ........................................................... –0.3V to 8V Pulsed <100ns ...................................... –0.3V to 10V PIN CONFIGURATION TOP VIEW SW 1 12 VOUT VIN 2 11 BURST SYNC 3 10 SS 13 SHDN 4 9 GND ILIM 5 RT 6 8 COMP 7 FB DE12 PACKAGE 12-LEAD (4mm × 3mm) PLASTIC DFN EXPOSED PAD IS PGND (PIN 13), MUST BE SOLDERED TO PCB TJMAX = 125°C, θJA = 45°C/W ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION LTC3458EDE#PBF LTC3458EDE#TRPBF 3458 12-Lead (4mm x 3mm) Plastic DFN Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC 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/ TEMPERATURE RANGE –40ºC to 85ºC ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3.3V, VOUT = 5V, RT = 200k, unless otherwise noted. PARAMETER Minimum VIN Operating Voltage Output Voltage Adjust Range Feedback Voltage Undervoltage (Exit Burst Mode Operation) Feedback Input Current Quiescent Current - Burst Mode Operation Quiescent Current - Shutdown Quiescent Current - Active NMOS Switch Leakage PMOS Switch Leakage NMOS Switch On Resistance PMOS Switch On Resistance Fixed NMOS Current Limit Maximum Duty Cycle Minimum Duty Cycle Frequency Accuracy Error Amplifier Transconductance Error Amplifier Source Current CONDITIONS TA = 0°C to 85°C TA = –40°C to 0°C 0°C to 85°C, VOUT = 3.3V –40°C to 0°C Below Feedback Voltage VFB = 1.23V VIN Current at 3.3V VOUT Current at 5V VIN Current at 3.3V VOUT Current at 0V VIN Current Switching VOUT = 5V VOUT = 5V RILIM = 124k VIN = 3.3V, fOSC = 1MHz RT = 200k MIN TYP MAX UNITS 1.4 1.5 V 1.4 1.7 V ● 2.0 7.5 V 1.21 1.23 1.25 V 1.20 1.25 V –4% V 1 50 nA 15 30 μA 5 10 μA 0.5 1 μA 1 3 μA 1 3 mA ● 0.05 5 μA ● 0.05 5 μA 0.3 Ω 0.4 Ω ● 1.4 1.6 A ● 80 90 % ● 0 % ● 0.85 1 1.15 MHz 100 μA/V 7 μA 3458fa 2 LTC3458 ELECTRICAL CHARACTERISTICS The ● denotes the specificat.


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