Features and Benefits
- Programmable Output Voltage Tracking
- Sense Resistor Optional
- Spread Spectrum Modulation for Low Noise
- Constant Frequency Current Mode Operation for Excellent Line and Load Transient Response
- Wide VIN Range: 2.75V to 9.8V
- Wide VOUT Range: 0.6V to VIN
- 0.6V ±1.5% Reference
- Low Dropout Operation: 100% Duty Cycle
- True PLL for Frequency Locking or Adjustment (Frequency Range: 250kHz to 750kHz)
- Selectable Burst Mode®/Pulse Skipping/Forced Continuous Operation
- Auxiliary Winding Regulation
- Internal Soft-Start Circuitry
- Power Good Output Voltage Monitor
- Output Overvoltage Protection
- Micropower Shutdown: IQ = 9µA
- Tiny Thermally Enhanced Leadless (4mm × 3mm) DFN or 16-lead SSOP Package
The LTC3808 is a synchronous step-down switching regulator controller that drives external complementary power MOSFETs using few external components. The constant frequency current mode architecture with MOSFET VDS sensing eliminates the need for a current sense resistor and improves efficiency.
Burst Mode operation provides high efficiency operation at light loads. 100% duty cycle provides low dropout operation, extending operating time in battery-powered systems.
The switching frequency can be programmed up to 750kHz, allowing the use of small surface mount inductors and capacitors. For noise sensitive applications, the LTC3808 can be externally synchronized from 250kHz to 750kHz. Burst Mode is inhibited during synchronization or when the SYNC/MODE pin is pulled low to reduce noise and RF interference. To further reduce EMI, the LTC3808 incorporates a novel spread spectrum frequency modulation technique.
The LTC3808 is available in the tiny footprint thermally enhanced DFN package or 16-lead SSOP package.
Protected by U.S. Patents including 5481178, 5929620, 6580258, 6304066, 5847554, 6611131, 6498466. Other Patents pending.
|LTC3809||PLL, Selectable Spread Spectrum, Power Good||3x3 DFN-10, MS-10E|
|LTC3809-1||Tracking||3x3 DFN-10, MS-10E|
|LTC3808||PLL, Selectable Spread Spectrum, Tracking Power Good||4x3 DFN-14, SSOP-16|
- One or Two Cell Lithium-Ion Powered Devices
- Notebook and Palmtop Computers, PDAs
- Portable Instruments
- Distributed DC Power Systems
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 769A is a high efficiency synchronous step-down DC/DC converter with output tracking and spread spectrum functions featuring the LTC3808EDE No RSENSE controller. The demo board provides 1.8V @ up to 5A output current from a 2.7V to 8V input voltage. A jumper allows the user to adjust the peak current limit, thereby setting the maximum output current to 5A, 3.5A or 2.5A.
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.