Features and Benefits
- 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
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.
- Cellular Telephones
- Wireless Modems
- Personal Information Appliances
- Portable Instruments
- Distributed Power Systems
- Battery-Powered Equipment
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 DC290 is a constant-frequency step-down converter using an LTC1877 or an LTC1878 monolithic synchronous regulator. The LTC1878 has an input voltage range of 2.65V < VIN < 6V and the LTC1877 has an input voltage range of 2.65V < VIN < 10V. The LTC1878 is optimized for low voltage operation and is ideally suited for single Li-Ion cell or 3-NiCd/NiMH cell applications. The LTC1877, with its higher voltage capability, is ideally suited for two Li-Ion cells or 4- to 6-NiCd/NiMH cell applications.
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.
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.