LTC3544B - Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA
Features
- 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
- Low Dropout Operation: 100% Duty Cycle
- Pulse Skipping at Low Load for Minimum Ripple
- 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
Typical Application
Description
The LTC3544B 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 LTC3544B well suited for single Li-Ion/polymer battery-powered applications. 100% duty cycle provides low dropout operation, extending battery runtime in portable systems. At moderate and low output load levels PWM pulse skip mode operation provides very low output ripple voltage for noise sensitive applications.
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 LTC3544B is available in a low profile (0.75mm) (3mm × 3mm) QFN package.
| Light Load Operation | |
| LTC3544 | Burst Mode (20mVpp), < 70uA Iq |
| LTC3544B | Pulse Skip Mode |
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC3544BEUD#PBF | 3x3 QFN-16 | UD | E | 05-08-1691 | Yes |
| LTC3544BEUD#TRPBF | 3x3 QFN-16 | UD | E | 05-08-1691 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3544BEUD#PBF | 3x3 QFN-16 | E | $4.21 | $2.95 | Yes | |
| LTC3544BEUD#TRPBF | 3x3 QFN-16 | E | $3.01 | Yes | ||
| Buy Now • Request Samples | ||||||
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 |
|---|---|---|---|
| DC1040A-B | LTC3544BEUD Demo Board | $125.00 | |
| Buy Now | |||
Applications
- Cellular Telephones
- Personal Information Appliances
- Wireless and DSL Modems
- Digital Still Cameras
- Media Players
- Portable Instruments
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Design Tools
LTspice
LTspice® software 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
Models for the following parts are available in LTspice:
LTC3544
LTC3544B
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
