60-V input step-down DC/DC controller draws 40-uA in battery-powered systems

November 09, 2012 // By Paul Buckley
Linear Technology Corporation has introduced a high voltage step-down DC/DC controller that draws 40 µA quiescent current in standby mode with the output enabled in Burst Mode operation.

The LTC3864 3.5 V to 60 V input supply range is designed to protect against high voltage transients, to operate continuously during automotive cold crank and covers a broad range of input sources and battery chemistries. The output voltage can be set from 0.8V to VIN due to its 100% duty cycle capability, making it well suited for 12 V or 24 V automotive, heavy equipment, industrial control, robotics and telecom applications.

The LTC3864 drives an external P-channel MOSFET, operates with a selectable fixed frequency between 50 kHz and 850 kHz, and is synchronizable to an external clock from 75 kHz to 750 kHz. The user can select from pulse skipping and low ripple Burst Mode operation during light loads. Its current-mode architecture provides easy loop compensation, fast transient response and excellent line regulation.

Output current sensing is accomplished by measuring the voltage drop across a sense resistor for highest accuracy. Additional features include programmable soft start or tracking, overvoltage protection, overcurrent and short-circuit protection, a power good output signal and FMEA (failure mode and effects analysis) verified for adjacent pin opens and shorts.

Availability and Pricing

The LTC3864 is offered in 12-pin thermally enhanced MSOP and 4 mm X 3 mm QFN packages. The LTC3864E and LTC3864I versions operate from -40 to 125°C junction temperature. The LTC3864H is guaranteed to operate from a -40 to 150°C operating junction temperature. The LTC3864MP is 100% tri-temperature tested and guaranteed to operate from -55 to 150°C operating junction temperature. The 1,000-piece price starts at $2.06 each.

More information about LTC3864 step-down DC/DC controller at www.linear.com/product/LTC3864