Linear Technology has announced the H- and MP-grade versions of the LT8705. This high efficiency (up to 98%) synchronous buck-boost DC/DC controller operates from input voltages above, below or equal to the regulated output voltage. The LT8705 operates over a 2.8V to 80V input voltage range and produces a fixed 1.3V to 80V output, using a single inductor with 4-switch synchronous rectification. Output power up to 250W can be delivered with a single device. Higher power can be achieved when multiple circuits are paralleled. These H- and MP-grade versions are guaranteed over operating junction temperatures from -40°C to 150°C and -55°C to 150°C, respectively.
The LT8705 has four feedback loops to regulate the input current/voltage, along with the output current/voltage. The input current and voltage feedback loops can prevent overloading of solar cells. The output current loop provides a regulated output current for a battery charger or current source. The operating frequency is selectable between 100kHz and 400kHz, and can be synchronised to an external clock. The LT8705 employs a proprietary current-mode control architecture for constant frequency operation in buck or boost mode and has powerful onboard quad N-channel MOSFET gate drivers. The user can select among forced continuous, discontinuous and Burst Mode operation to maximise light load efficiency.
Additional features include servo pins to indicate which feedback loops are active, a 3.3V/12mA LDO, adjustable soft-start, onboard die temperature monitor and ±1.30% reference voltage accuracy over an operating junction temperature range of -55°C to 150°C. The LT8705 is available in a 38-pin 5mm x 7mm QFN, and also a 38-lead TSSOP package with additional pin spacing for high voltage operation. Pricing starts at $6.83 each in 1,000-piece quantities. For more information, visit www.linear.com/product/LT8705.
Summary of Features: LT8705
- Single Inductor Architecture
- Operation with Input Voltages Above, Below or Equal to the Output Voltage
- 2.8V to 80V Input Voltage Range
- 1.3V to 80V Output Voltage Range
- Four Regulation Loops (Input V/I & Output V/I)
- Synchronous Rectification
- Up to 98% Efficiency
- On Chip Quad MOSFET Gate Drivers
- 250 Watts Output Power Capable with a Single Device
- Fixed Synchronizable Operating Frequency from 100kHz to 400kHz
- Servo Pins Indicating which Feedback Pins are Active
- 3.3V/12mA Onboard LDO
- 38-Pin 5mm x 7mm QFN & TSSOP Package with Additional Pin Spacing
- Extended & Industrial Grades: -40°C to 125°C Operating Junction Temp
- Automotive Temp Grade: -40°C to 150°C Operating Junction Temp
- Military Temp Grade: -55°C to 150°C Operating Junction Temp
