LTC3549 - 250mA Low VIN Buck Regulator in 2mm x 3mm DFN
- 1.6V to 5.5V Input Voltage Range
- Internal Soft-Start
- Low Ripple Burst Mode® Operation
Output Ripple: <20mVP-P
- 2.25MHz Constant-Frequency Operation
- High Efﬁ ciency: Up to 93%
- 250mA Output Current (VIN = 1.8V, VOUT = 1.2V)
- 450mA Peak Inductor Current
- No Schottky Diode Required
- Low Dropout Operation: 100% Duty Cycle
- 0.611V Reference Voltage
- Stable with Ceramic Capacitors
- Shutdown Mode Draws <1µA Supply Current
- Current Mode Operation for Excellent Line and Load Transient Response
- Overtemperature Protection
- Available in a Low Proﬁ le (0.75mm) 6-Lead (2mm x 3mm) DFN Package
The LTC3549 is a high efficiency, monolithic synchronous buck regulator using a constant-frequency, current mode architecture. The output voltage is adjusted via an external resistor divider.
A fixed switching frequency of 2.25MHz is supported. This switching frequency allows the use of small surface mount inductors and capacitors, including ceramics.
Supply current during Burst Mode operation is only 50µA dropping to < 1µA in shutdown. The 1.6V to 5.5V input voltage range makes the LTC3549 ideally suited for single cell Li-Ion, Li-Metal and 2-cell alkaline, NiCd or NiMH battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems. Burst Mode operation can be user-enabled, increasing efficiency at light loads, further extending battery life.
The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Internal soft-start offers controlled output voltage rise time at startup without the need for external components.
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 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
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|DC992A||LTC3549EDCB Demo Board||$75.00|
- 2 AA-Cell Applications
- Cellular Phones
- Digital Cameras
- MP3 Players
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