Analog Devices Inc. LT8705/A 4-Switch Buck-Boost DC/DC Controllers

Analog Devices Inc. LT8705/A 4-Switch Buck-Boost DC/DC Controllers are high-performance and operate from input voltages above, below or equal to the output voltage. The LT8705/A has integrated input current, input voltage, output current, and output voltage feedback loops. The LT8705/A is compatible with most solar, automotive, telecom, and battery-powered systems. The controllers feature a wide 2.8V to 80V input and 1.3V to 80V output range.

The Analog Devices LT8705A includes a MODE pin to select among Burst Mode® operation, discontinuous or continuous conduction mode at light loads. Additional features include a 3.3V/12mA LDO, a synchronizable fixed operating frequency, and onboard gate drivers.

Features

Single inductor allows V_IN above, below, or equal to regulated V_OUT
V_IN range 2.8V (need EXTVCC > 6.4V) to 80V
1.3V to 80V V_OUT range
Quad N-channel MOSFET gate drivers
Up to 98% efficiency for synchronous rectification
Input and output current monitor pins

Integrated input current, input voltage, output current, and output voltage feedback loops
100kHz to 400kHz synchronizable fixed frequency
Clock output usable to monitor die temperature
Available in 38-lead (5mm × 7mm) QFN and TSSOP
Packages with the TSSOP modified for improved high voltage operation

Applications

High voltage buck-boost converters
Input or output current limited converters

Additional Resources

Eliminate Switching Noise with 4-Switch Buck-Boost Controller with Pass-Thru Capability

There are several dc-to-dc converter topologies that can perform both step-up and step-down operations, from SEPIC to 4-switch topologies, but none of these solutions pass the input voltage directly to the output without actively switching — until now, that is.

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