LTC3605 - 15V, 5A Synchronous Step-Down Regulator

Features

  • High Efficiency: Up to 96%
  • 5A Output Current
  • 4V to 15V VIN Range
  • Integrated Power N-Channel MOSFETs
    (70mΩ Top and 35mΩ Bottom)
  • Adjustable Frequency 800kHz to 4MHz
  • PolyPhase® Operation (Up to 12 Phases)
  • Output Tracking
  • 0.6V ±1% Reference Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Shutdown Mode Draws Less Than 15μA Supply Current
  • Available in 24-Pin (4mm × 4mm) QFN Package

Typical Application

LTC3605 Typical Application
LTC3605 Typical Application

Description

The LTC3605 is a high efficiency, monolithic synchronous buck regulator using a phase lockable controlled on-time constant frequency, current mode architecture. PolyPhase operation allows multiple LTC3605 regulators to run out of phase while using minimal input and output capacitance. The operating supply voltage range is from 15V down to 4V, making it suitable for dual lithium-ion battery inputs as well as point of load power supply applications from a 12V or 5V rail.

The operating frequency is programmable from 800kHz to 4MHz with an external resistor. The high frequency capability allows the use of small surface mount inductors. For switching noise sensitive applications, it can be externally synchronized from 800kHz to 4MHz. The PHMODE pin allows user control of the phase of the outgoing clock signal. The unique constant frequency/controlled on-time architecture is ideal for high step-down ratio applications that are operating at high frequency while demanding fast transient response. Two internal phase-lock loops synchronize the internal oscillator to the external clock and also servos the regulator on-time to lock on to either the internal clock or the external clock if it’s present.

Packaging

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

QFN-24

LTC3605 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3605AEUF#PBF QFN 24 E $6.07 $4.25 View
LTC3605AEUF#TRPBF QFN 24 E $4.31 View
LTC3605AIUF#PBF QFN 24 I $7.14 $5.00 View
LTC3605AIUF#TRPBF QFN 24 I $5.06 View
LTC3605EUF#PBF QFN 24 E $6.07 $4.25 View
LTC3605EUF#TRPBF QFN 24 E $4.31 View
LTC3605IUF#PBF QFN 24 I $7.14 $5.00 View
LTC3605IUF#TRPBF QFN 24 I $5.06 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 demo boards are offered free of charge to qualified customers. Contact your local sales office or distributor to request 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
DC1215A LTC3605EUF Demo Board | 14V, 5A PolyPhase Synchronous Step Down Regulator $150.00
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Applications

  • Point of Load Power Supply
  • Portable Instruments
  • Distributed Power Systems
  • Battery-Powered Equipment

Simulate

LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice IV
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice IV does not automatically open after clicking the link above, 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

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Related models available in LTspice IV
LTC3605

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