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Overview
Features and Benefits
- Single Inductor Allows VIN Above, Below, or Equal to VOUT
- Six Independent Forms of Regulation
- VIN Current (Forward and Reverse)
- VOUT Current (Forward and Reverse)
- VIN and VOUT Voltage
- Forward and Reverse Discontinuous Conduction Mode Supported
- Supports MODE and DIR Pin Changes While Switching
- VINCHIP Range 2.8V (Need EXTVCC > 6.4V) to 80V
- VOUT Range: 1.3V to 80V
- Synchronous Rectification: Up to 99% Efficiency
- Available in 40-Lead (5mm × 8mm) QFN with High Voltage Pin Spacing
Product Details
The LT®8708 is a high performance buck-boost switching regulator controller that operates from an input voltage that can be above, below or equal to the output voltage. Features are included to simplify bidirectional power conversion in battery/capacitor backup systems and other applications that may need regulation of VOUT, VIN, IOUT, and/or IIN. Forward and reverse current can be monitored and limited for the input and output sides of the converter. All four current limits (forward input, reverse input, forward output and reverse output) can be set independently using four resistors on the PCB.
The MODE pin can select between discontinuous conduction mode (DCM), continuous conduction mode (CCM), hybrid conduction mode (HCM) and Burst Mode® operation. In combination with the DIR (direction) pin, the chip can be configured to process power only from VIN to VOUT or only from VOUT to VIN. With a wide 2.8V to 80V input and 1.3V to 80V output range, the LT8708 is compatible with most solar, automotive, telecom and battery-powered systems.
Applications
- High Voltage Buck-Boost Converters
- Bidirectional Charging System
- Automotive 48V 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 (2)
Tools & Simulations
LTspice
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:
LTpowerCAD
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
Reference Materials
Product Selector Card (1)
Bidirectional DC-to-DC Ideal for Power Redundancy and Backup
Bi-Directional Synchronous 4-Switch Buck-Boost Converter
Technical Articles (1)
Analog Dialogue (1)
Press Releases (1)
Design Resources
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.
