Features and Benefits
- 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
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.
- Point-of-Load Supplies
- Distributed Power Supplies
- Portable Computer Systems
- DDR Memory Termination
- Handheld Devices
Product Lifecycle 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.
Evaluation Kits (2)
Demonstration circuit 1572 is a dual output regulator consisting of two constant-frequency step-down converters, based on the LTC3615 dual channel monolithic synchronous buck regulator in the TSSOP exposed pad package. The DC1572 has an input voltage range of 2.25V to 5.5V, with each regulator capable of delivering up to 3A of output current.
Demonstration circuit 1435 is a dual output regulator consisting of two constant-frequency step-down converters, based on the LTC3615 dual channel monolithic synchronous buck regulator in the 4mm × 4mm QFN-24 package. The DC1435 has an input voltage range of 2.25V to 5.5V, with each regulator capable of delivering up to 3A of output current. The DC1435 can operate in Burst Mode®, pulse-skip or forced continuous mode. In shutdown, the DC1435 requires less than 100 uA total. The DC1435 is a very efficient circuit: over 90% for either circuit. The LTC3615 comes in a 24 Pin QFN or leaded package, which each having an exposed pad on the bottom-side of the IC for better thermal performance.
Documentation & Resources
LTC3615: Dual 4MHz, 3A Synchronous Step-Down DC/DC Converter Data Sheet7/18/2013584K
R457 Reliability Data3/26/201865 K
DC1435A - Demo Manual6/25/20101M
DC1572A - Demo Manual6/15/2010981K
Tools & Simulations
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.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
To open the project file for this circuit:
Step 1: Download and install LTpowerCAD on your computer.
Step 2: Click on the link(s) in the section below to download part-specific project files.
Step 3: If the project file doesn't run, right-click the link and select "Save Target As." Then start the LTpowerCAD tool and open the project file by selecing "Open Project" from the "File" menu.
Design tools for the following parts are available in LTpowerCAD:
Reference Designs (1)
Stratix V Advanced System Development Board
Stratix V Advanced System Development Board
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