Overview

Features and Benefits

  • High Efficiency, 500mA Buck Plus 300mA VLDO Regulator
  • Auto Start-Up Powers Buck Output Prior to VLDO/Linear Regulator Output
  • Independent 500mA High Efficiency Buck (VIN: 2.7V to 5.5V)
  • 300mA VLDO Regulator with 30mA Standalone Mode
  • No External Schottky Diodes Required
  • Fixed Buck Output Voltage: 1.875V
  • VLDO Input Voltage Range (LVIN: 1.6V to 5.5V)
  • Fixed VLDO Output Voltage: 1.5V
  • Selectable Fixed Frequency, Pulse-Skip Operation or Burst Mode® Operation
  • Short-Circuit Protected
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Shutdown Current: <3μA
  • Constant Frequency Operation: 2.25MHz
  • Low Dropout Buck Operation: 100% Duty Cycle
  • Small, Thermally Enhanced, 10-Lead (3mm × 3mm) DFN Package

Product Details

The LTC3541-2 combines a synchronous buck DC/DC converter with a very low dropout linear regulator (VLDOregulator) and internal feedback resistor networks to provide two output voltages from a single input voltage with minimal external components. When configured for dual output operation, the LTC3541-2’s auto start-up feature will bring the 1.875V buck output into regulation in a controlled manner, prior to enabling the 1.5V VLDO output without the need for external pin control. The 1.5V VLDO/linear regulator output prior to 1.875V buck output sequencing may also be obtained via external pin control. The input voltage range is ideally suited for Li-Ion battery applications powering sub-3.3V logic from 5V or 3.3V rails.

The synchronous buck converter provides a high efficiency output, typically 90%. It can provide up to 500mA of output current while switching at 2.25MHz, allowing the use of small surface mount inductors and capacitors. A mode select pin allows Burst Mode operation to be enabled for higher efficiency at light load currents, or disabled for lower noise, constant frequency operation.

The VLDO regulator provides a low noise, low voltage output capable of providing up to 300mA of output current using only a 2.2μF ceramic capacitor. The input supply voltage of the VLDO regulator (LVIN) may come from the buck regulator output or a separate supply.

Options Vout Switcher (V) Vout VLDO Auto Start Up Sequencing
LTC3541 Adj. down to 0.8V Adj. down to 0.4V Switcher, then VLDO
LTC3541-1 Adj. down to 0.8V Adj down to 0.4V VLDO, then switcher
LTC3541-2 1.875V fixed 1.5V fixed Switcher, then VLDO
LTC3541-3 1.8V fixed 1.575 fixed VLDO, then switcher

Applications

  • Digital Cameras
  • Cellular Phones
  • PC Cards
  • Wireless and DSL Modems
  • Other Portable Power Systems

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Tools & Simulations

LTspice

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.

LTspice

Models for the following parts are available in LTspice:

LTC3541
LTC3541-1
LTC3541-2
LTC3541-3

Product Recommendations

LTC3541-2 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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