LTC3615 - Dual 4MHz, 3A Synchronous Step-Down DC/DC Converter

Features

  • High Efficiency: Up to 94%
  • Dual Outputs with 2 × 3A Output Current Capability
  • Low Output Ripple Burst Mode® Operation: IQ = 130μA
  • 2.25V to 5.5V Input Voltage Range
  • ±1% Output Voltage Accuracy
  • Output Voltages Down to 0.6V
  • Programmable Slew Rate at Switch Pins
  • Low Dropout Operation: 100% Duty Cycle
  • Shutdown Current ≤1μA
  • Adjustable Switching Frequency Up to 4MHz
  • Internal or External Compensation
  • Selectable Pulse-Skipping/Forced Continuous/ Burst Mode Operation with Adjustable Burst Clamp
  • Optional Active Voltage Positioning (AVP) with Internal Compensation
  • Selectable 0°/90°/180° (LTC3615) or selectable 140°/180° (LTC3615-1) Phase Shift Between Channels
  • Fixed Internal and Programmable External Soft-Start
  • Accurate Start-Up Tracking Capability
  • DDR Memory Mode IOUT = ±1.5A
  • Available in 4mm × 4mm QFN-24 and eTSSOP-24 Packages

Typical Application

LTC3615 Typical Application
LTC3615 Typical Application

Description

The LTC3615/LTC3615-1 are dual 3A synchronous stepdown regulators using a current mode, constant-frequency architecture. The DC supply current is only 130μA (Burst Mode operation at no-load) while maintaining the output voltages, dropping to zero current in shutdown. The 2.25V to 5.5V input supply range makes the parts ideally suited for single Li-Ion applications. 100% duty cycle capability provides low dropout operation, which extends operating time in battery-operated systems.

The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. 0°, 90°, or 180° (LTC3615) or 140°/180° (LTC3615-1) of phase shift between the two channels can be selected to minimize input current ripple and output voltage ripple in a dual 3A or single 6A output configuration. Programmable slew rate limiting reduces EMI, and external synchronization can be applied up to 4MHz.

The internal synchronous switches increase efficiency and eliminate the need for external catch diodes, saving external components and board space.

The LTC3615/LTC3615-1 are offered in leadless 24-pin 4mm × 4mm QFN and thermally enhanced 24-pin eTSSOP packages.

Packaging

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

QFN-24, TSSOP-24

LTC3615 Package Drawing
LTC3615 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LTC3615EFE#PBF TSSOP 24 E $5.86 $4.10 View
LTC3615EFE#TRPBF TSSOP 24 E $4.16 View
LTC3615EFE-1#PBF TSSOP 24 E $5.86 $4.10 View
LTC3615EFE-1#TRPBF TSSOP 24 E $4.16 View
LTC3615EUF#PBF QFN 24 E $5.64 $3.95 View
LTC3615EUF#TRPBF QFN 24 E $4.01 View
LTC3615EUF-1#PBF QFN 24 E $5.64 $3.95 View
LTC3615EUF-1#TRPBF QFN 24 E $4.01 View
LTC3615HFE#PBF TSSOP 24 H $7.64 $5.35 View
LTC3615HFE#TRPBF TSSOP 24 H $5.41 View
LTC3615HFE-1#PBF TSSOP 24 H $7.64 $5.35 View
LTC3615HFE-1#TRPBF TSSOP 24 H $5.41 View
LTC3615HUF#PBF QFN 24 H $7.14 $5.00 View
LTC3615HUF#TRPBF QFN 24 H $5.06 View
LTC3615HUF-1#PBF QFN 24 H $7.14 $5.00 View
LTC3615HUF-1#TRPBF QFN 24 H $5.06 View
LTC3615IFE#PBF TSSOP 24 I $6.89 $4.82 View
LTC3615IFE#TRPBF TSSOP 24 I $4.88 View
LTC3615IFE-1#PBF TSSOP 24 I $6.89 $4.82 View
LTC3615IFE-1#TRPBF TSSOP 24 I $4.88 View
LTC3615IUF QFN 24 I $6.64 $4.65 View
LTC3615IUF#PBF QFN 24 I $6.64 $4.65 View
LTC3615IUF#TR QFN 24 I $4.71 View
LTC3615IUF#TRPBF QFN 24 I $4.71 View
LTC3615IUF-1#PBF QFN 24 I $6.64 $4.65 View
LTC3615IUF-1#TRPBF QFN 24 I $4.71 View
LTC3615MPFE#PBF TSSOP 24 MP $18.57 $13.00 View
LTC3615MPFE#TRPBF TSSOP 24 MP $13.06 View
LTC3615MPFE-1#PBF TSSOP 24 MP $18.57 $13.00 View
LTC3615MPFE-1#TRPBF TSSOP 24 MP $13.06 View
LTC3615MPUF#PBF QFN 24 MP $17.93 $12.55 View
LTC3615MPUF#TRPBF QFN 24 MP $12.61 View
LTC3615MPUF-1#PBF QFN 24 MP $17.93 $12.55 View
LTC3615MPUF-1#TRPBF QFN 24 MP $12.61 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
DC1435A LTC3615EUF Demo Board (QFN) | 2.25V ≤ VIN ≤ 5.5V, VOUT1 = 1.8V to 3.3V @ 3A, VOUT2 = 1.2V to 1.8V @ 3A . Contact Factory
DC1572A LTC3615EFE Demo Board (TSSOP)| 2.25V ≤ VIN ≤ 5.5V, VOUT1 = 1.8V to 3.3V @ 3A, VOUT2 = 1.2V to 1.8V @ 3A. Contact Factory
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Click here to view our complete list of demo boards

Applications

  • Point-of-Load Supplies
  • Distributed Power Supplies
  • Portable Computer Systems
  • DDR Memory Termination
  • Handheld Devices

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Design Tools

LTpowerCAD

The LTpowerCAD II design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LTC3615
LTC3615 (Dual Channel)
LTC3615 (Single Channel)

LTspiceIV

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. Click here to download LTspice IV

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.

Models for the following parts are available in LTspice IV:
LTC3615

Technical Support