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Linear Technology Corp. announces the H- and MP-grade versions of the LT8705. This high efficiency (up to 98 percent) synchronous buck-boost DC/DC controller operates from input voltages above, below or equal to the regulated output voltage. The LT8705 operates over a 2.8 to 80V input voltage range and produces a fixed 1.3 to 80 V output, using a single inductor with 4-switch synchronous rectification. Output power up to 250 W 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°t o 150°C and -55° 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 synchronized 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 maximize light load efficiency.
Additional features include servo pins to indicate which feedback loops are active, a 3.3 V/12 mA LDO, adjustable soft-start, onboard die temperature monitor and ±1.30% reference voltage accuracy over an operating junction temperature range of -55° to 150°C. The LT8705 is available in a 38-pin 5 x 7 mm 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.
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