LT3581
Info : RECOMMENDED FOR NEW DESIGNS
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LT3581

3.3A Boost/Inverting DC/DC Converter with Fault Protection

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Info : RECOMMENDED FOR NEW DESIGNS tooltip
Info : RECOMMENDED FOR NEW DESIGNS tooltip
Part Details
Part Models 10
1ku List Price Starting From $2.95
Features
  • 3.3A, 42V Combined Power Switch
  • Master/Slave (1.9A/1.4A) Switch Design
  • Output Short Circuit Protection
  • Wide Input Range: 2.5V to 22V Operating, 40V Maximum Transient
  • Switching Frequency Up to 2.5MHz
  • Easily Configurable as a Boost, SEPIC, Inverting or Flyback Converter
  • User Configurable Undervoltage Lockout
  • Low VCESAT Switch: 250mV at 2.75A (Typical)
  • Can be Synchronized to External Clock
  • Can Be Synchronized to other Switching Regulators
  • High Gain SHDN Pin Accepts Slowly Varying Input Signals
  • 14-Pin 4mm × 3mm DFN and 16-Lead MSE Packages
Additional Details
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The LT3581 is a PWM DC/DC converter with built-in fault protection features to aid in protecting against output shorts, input/output overvoltages, and overtemperature conditions. The part consists of a 42V master switch, and a 42V slave switch that can be tied together for a total current limit of 3.3A.

The LT3581 is ideal for many local power supply designs. It can be easily configured in Boost, SEPIC, Inverting or Flyback configurations, and is capable of generating 12V at 830mA, or –12V at 625mA from a 5V input. In addition, the LT3581’s slave switch allows the part to be configured in high voltage, high power charge pump topologies that are very efficient and require fewer components than traditional circuits.

The LT3581’s switching frequency range can be set between 200kHz and 2.5MHz. The part may be clocked internally at a frequency set by the resistor from the RT pin to ground, or it may be synchronized to an external clock. A buffered version of the clock signal is driven out of the CLKOUT pin, and may be used to synchronize other compatible switching regulator ICs to the LT3581.

The LT3581 also features innovative SHDN pin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function. Additional features such as frequency foldback and soft-start are integrated. The LT3581 is available in 14-Pin 4mm × 3mm DFN and 16-Lead MSE packages.

Applications

  • Local Power Supply
  • Vacuum Fluorescent Display (VFD) Bias Supplies
  • TFT-LCD Bias Supplies
  • Automotive Engine Control Unit (ECU) Power
Part Models 10
1ku List Price Starting From $2.95

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Documentation

Documentation

Video

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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Product Lifecycle

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Feb 20, 2022

- 21_0269

Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products

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Oct 11, 2022

- 22_0244

Epoxy Change from Henkel 8290 to 8290A for MSOP Package

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Feb 4, 2020

- 20_0132

Laser Top Mark for 16-Lead MSOP Packages Assembled in ADPG and UTAC

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Filter by Model

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Part Models

Product Lifecycle

PCN

Feb 20, 2022

- 21_0269

arrow down

Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products

LT3581EDE#PBF

PRODUCTION

LT3581EDE#TRPBF

PRODUCTION

LT3581HDE#PBF

PRODUCTION

LT3581HDE#TRPBF

PRODUCTION

LT3581IDE#PBF

PRODUCTION

LT3581IDE#TRPBF

PRODUCTION

Oct 11, 2022

- 22_0244

arrow down

Epoxy Change from Henkel 8290 to 8290A for MSOP Package

LT3581EMSE#PBF

PRODUCTION

LT3581EMSE#TRPBF

PRODUCTION

LT3581IMSE#PBF

PRODUCTION

LT3581IMSE#TRPBF

PRODUCTION

Feb 4, 2020

- 20_0132

arrow down

Laser Top Mark for 16-Lead MSOP Packages Assembled in ADPG and UTAC

LT3581EMSE#PBF

PRODUCTION

LT3581EMSE#TRPBF

PRODUCTION

LT3581IMSE#PBF

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Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 2

reference details image

DC1424A-A

LT3581EMSE Demo Board | VIN = 5V to 10V, VOUT1 = 12V @ 900mA

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DC1424A-A

LT3581EMSE Demo Board | VIN = 5V to 10V, VOUT1 = 12V @ 900mA

LT3581EMSE Demo Board | VIN = 5V to 10V, VOUT1 = 12V @ 900mA

Product Detail

Demonstration circuits 1424A-A and 1424A-B feature the LT3581 in Boost and Inverting Regulator configurations, respectively. The Boost is designed to convert a 5V to 10V input source to 12V at 900mA, and the Inverter a 5V to 12V to -12V at 750mA. DC1424A-A is designed to survive output short circuit events with the external MOSFET installed at the output as default. The demo board includes an option to install the MOSFET at the input side. Install Q1 and R1 on the back of the board and refer to Figure 4 for other instructions. DC1424A-B can easily be converted into a SEPIC Converter by swapping L2 and D2 from their respective locations as shown in Figure 5. The LT3581 includes a 42V Master and Slave switch combination with 3.3A total current and can be used in many configurations such as Boost, SEPIC, CUK and Flyback.

reference details image

DC1424A-B

LT3581EMSE Demo Board | VIN = 5V to 12V, VOUT1 = –12V @ 750mA

zoom

DC1424A-B

LT3581EMSE Demo Board | VIN = 5V to 12V, VOUT1 = –12V @ 750mA

LT3581EMSE Demo Board | VIN = 5V to 12V, VOUT1 = –12V @ 750mA

Product Detail

Demonstration circuits 1424A-A and 1424A-B feature the LT3581 in Boost and Inverting Regulator configurations, respectively. The Boost is designed to convert a 5V to 10V input source to 12V at 900mA, and the Inverter a 5V to 12V to -12V at 750mA. DC1424A-A is designed to survive output short circuit events with the external MOSFET installed at the output as default. The demo board includes an option to install the MOSFET at the input side. Install Q1 and R1 on the back of the board and refer to Figure 4 for other instructions. DC1424A-B can easily be converted into a SEPIC Converter by swapping L2 and D2 from their respective locations as shown in Figure 5. The LT3581 includes a 42V Master and Slave switch combination with 3.3A total current and can be used in many configurations such as Boost, SEPIC, CUK and Flyback. It has a 2.5V to 22V operating input range, UVLO, soft-start, programmable switching frequency and many other popular features.

Tools & Simulations

Tools & Simulations 1

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

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