LTC1877 - High Efficiency Monolithic Synchronous Step-Down Regulator
Features
- High Efficiency: Up to 95%
- Very Low Quiescent Current: Only 10μA During Operation
- 600mA Output Current at VIN = 5V
- 2.65V to 10V Input Voltage Range
- 550kHz Constant-Frequency Operation
- No Schottky Diode Required
- Low Dropout Operation: 100% Duty Cycle
- Synchronizable from 400kHz to 700kHz
- Selectable Burst Mode® Operation or Pulse-Skipping Mode
- 0.8V Reference Allows Low Output Voltages
- Shutdown Mode Draws < 1μA Supply Current
- ±2% Output Voltage Accuracy
- Current Mode Control for Excellent Line and Load Transient Response
- Overcurrent and Overtemperature Protected
- Available in 8-Lead MSOP Package
Typical Application
Description
The LTC1877 s a high efficiency monolithic synchronous buck regulator using a constant-frequency, current mode architecture. Supply current during operation is only 10μA and drops to < 1μA in shutdown. The 2.65V to 10V input voltage range makes the LTC1877 ideally suited for both single and dual Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems.Switching frequency is internally set at 550kHz, allowing the use of small surface mount inductors and capacitors. For noise sensitive applications the LTC1877 can be externally synchronized from 400kHz to 700kHz. Burst Mode operation is inhibited during synchronization or when the SYNC/MODE pin is pulled low, preventing low frequency ripple from interfering with audio circuitry.
The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.8V feedback reference voltage. The LTC1877 is available in a space saving 8-lead MSOP package. Lower input voltage applications (less than 7V abs max) should refer to the LTC1878 data sheet.
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 |
|---|---|---|---|---|---|
| LTC1877EMS8#PBF | MS-8 | MS8 | E | 05-08-1660 | Yes |
| LTC1877EMS8#TRPBF | MS-8 | MS8 | E | 05-08-1660 | Yes |
| LTC1877IMS8#PBF | MS-8 | MS8 | I | 05-08-1660 | Yes |
| LTC1877IMS8#TRPBF | MS-8 | MS8 | I | 05-08-1660 | 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 | |
|---|---|---|---|---|---|---|
| LTC1877EMS8#PBF | MS-8 | E | $3.43 | $2.90 | Yes | |
| LTC1877EMS8#TRPBF | MS-8 | E | $2.96 | Yes | ||
| LTC1877IMS8#PBF | MS-8 | I | $4.87 | $3.41 | Yes | |
| LTC1877IMS8#TRPBF | MS-8 | I | $3.47 | 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 |
|---|---|---|---|
| DC290A-A | LTC1877EMS8 Demo Board | 2.65V to 10V Input, 1.5V to 3.3Vout @ 600mA | $100.00 | |
| Buy Now | |||
Applications
- Cellular Telephones
- Wireless Modems
- Personal Information Appliances
- Portable Instruments
- Distributed Power Systems
- Battery-Powered Equipment
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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:
LTC1877
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.
