Linear Technology Introduces High Efficiency Synchronous Buck-Boost DC/DC Controller

Photocoupler

Linear Technology Corporation (Linear Technology Corporation) introduced a very high efficiency (up to 98%) of the synchronous buck - boost DC / DC controller the LTC3789, the device is higher than, lower than or equal to the input voltage of the stable output Voltage work. High-power boost and buck circuits typically rely on a transformer or two DC/DC converters, one for boost conversion and the other for buck conversion. Operating in a single inductor and 4-switch synchronous rectification mode, the LTC3789 can deliver up to 150W of output power in a single device. When multiple circuits are connected in parallel, even higher output power can be provided.

Operating from an optional fixed frequency of 200kHz to 600kHz, the LTC3789 can also be synchronized to an external clock of the same range using its integrated phase-locked loop (PLL). The wide input range of 4V to 38V, the output range of 0.8V to 38V, and seamless transition between operating modes make the device ideal for a wide range of applications including industrial control, automotive, solar and high-power battery-powered systems.

In buck or boost mode, the LTC3789 uses a proprietary current mode control architecture for constant frequency operation with four powerful N-channel MOSFET gate drivers. The LTC3789 also provides an accurate constant current regulation loop to regulate the input or output current over a wide input voltage range. The input current limit feature prevents input supply overload and the output current limit provides an easy solution for stable output current applications such as battery chargers or LED drivers. The device provides fault protection for overvoltage, overcurrent, and short-circuit conditions in all operating modes. In addition, the LTC3789 disconnects the input voltage and output voltage during shutdown. Users can choose continuous or pulse skip mode to maximize light load efficiency. In addition, the LTC3789 features an adjustable soft-start, power-good output and ±1.5% reference accuracy over the operating junction temperature range of -40°C to 125°C.

The LTC3789 is available in 28-pin 4mm x 5mm QFN and 28-lead SSOP packages. The 1,000-piece purchase price is $4.65 per piece. For more information, please visit

Performance Summary: LTC3789

· Single inductor architecture

· Operates with an input voltage higher than, lower than or equal to the output voltage

· 4V to 38V input voltage range

· 0.8V to 38V output voltage range

· Programmable input or output current limit

· Synchronous rectification

· Up to 98% efficiency

· Built-in MOSFET gate driver

· Can provide 150W output power

· Output disconnection during shutdown

· PLL fixed operating frequency from 200kHz to 600kHz

· Power good output signal

· ±1.5% reference voltage accuracy over the -40oC to +125oC temperature range

· Current mode control for fast transient response and very easy loop compensation

· Overvoltage and overcurrent protection

· 5.5V internal and external VCC LDO