Power Management Switching Regulator Step-Up (Boost) Regulators Internal Power Switch Boost
Power Management Switching Regulator Flyback, Forward and Isolated Controllers
 Power Management Switching Regulator Inverting Regulators
 Power Management Switching Regulator LCD/CCD/OLED Bias
 Power Management Switching Regulator SEPIC Regulators

LT3581 - 3.3A Boost/Inverting DC/DC Converter with Fault Protection

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

Typical Application

LT3581 Typical Application
LT3581 Typical Application

Description

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.

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

DFN-14, MS-16

LT3581 Package Drawing
LT3581 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT3581EDE#PBF DFN 14 E $3.50 $2.45 View
LT3581EDE#TRPBF DFN 14 E $2.51 View
LT3581EMSE#PBF MSOP 16 E $3.64 $2.55 View
LT3581EMSE#TRPBF MSOP 16 E $2.61 View
LT3581IDE#PBF DFN 14 I $3.89 $2.72 View
LT3581IDE#TRPBF DFN 14 I $2.78 View
LT3581IMSE#PBF MSOP 16 I $4.04 $2.83 View
LT3581IMSE#TRPBF MSOP 16 I $2.89 View
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1424A-A LT3581EMSE Demo Board | VIN= 5V to 10V, VOUT1 = 12V @ 900mA $175.00
DC1424A-B LT3581EMSE Demo Board | VIN= 5V to 12V, VOUT1 = -12V @ 750mA $175.00
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Click here to view our complete list of demo boards

Applications

  • Local Power Supply
  • Vacuum Fluorescent Display (VFD) Bias Supplies
  • TFT-LCD Bias Supplies
  • Automotive Engine Control Unit (ECU) Power

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Related models available in LTspice IV
LT3581

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