Features and Benefits
- High Efficiency: Up to 95%
- Four Independent Regulators Provide Up to 300mA, 200mA, 200mA and 100mA Output Current
- 2.25V to 5.5V Input Voltage Range
- 2.25MHz Constant-Frequency Operation
- No Schottky Diodes Required
- Extremely Low Channel-to-Channel Transient Crosstalk
- Low Ripple (20mVP-P) Burst Mode Operation:
- IQ = 70µA (All Channels On)
- 0.8V Reference Allows Low Output Voltages
- Shutdown Mode Draws <1µA Supply Current
- Current Mode Operation for Excellent Line and Load Transient Response
- Overtemperature Protected
- Low Profile (3mm × 3mm) 16-Lead QFN Package
The LTC3544 is a quad, high efficiency, monolithic synchronous buck regulator using a constant-frequency, current mode architecture. The four regulators operate independently with separate run pins. The 2.25V to 5.5V input voltage range makes the LTC3544 well suited for single Li-Ion/polymer battery-powered applications. 100% duty cycle provides low dropout operation, extending battery runtime in portable systems. Low ripple Burst Mode® operation increases efficiency at light loads, further extending battery runtime with typically only 20mV of ripple.
Switching frequency is internally set to 2.25MHz, allowing the use of small surface mount inductors and capacitors. The internal synchronous switches increase efficiency and eliminate the need for external Schottky diodes. Low output voltages are easily supported with the 0.8V feedback reference voltage.
The LTC3544 is available in a low profile (0.75mm) (3mm × 3mm) QFN package.
|Light Load Operation|
|LTC3544||Burst Mode (20mVP-P), <70µa IQ|
|LTC3544B||Pulse Skip Mode|
- Cellular Telephones
- Personal Information Appliances
- Wireless and DSL Modems
- Digital Still Cameras
- Media Players
- Portable Instruments
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 (1)
Demonstration circuit 1040 is a quad output regulator consisting of four constant-frequency step-down converters integrated into the LTC3544. DC1040 has an input voltage range of 2.25V to 5.5V, with regulators capable of delivering 100mA, 200mA, 200mA and 300mA of output current. The four regulators operate independently with individual RUN pins and enter pulse skipping mode at low loads to reduce output ripple. The "-A" version is for the LTC3544EUD (Burst Mode) and the "-B" version is for the LTC3544BEUD (Pulse Skipping Mode).
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:
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.
Sample & Buy
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.