60V dual output synchronous step-down controller: 29µA standby

April 16, 2015 // By Graham Prophet
LTC3892 is a high voltage dual output synchronous step-down DC/DC controller that draws 29 µA when one output is active and 34 µA when both outputs are enabled. The 4.5V to 60V input supply range is designed to protect against high voltage transients, ensuring continuous operation during automotive cold crank and to accommodate a broad range of input sources and battery chemistries.

Each output can be set from 0.8V to 99% of V IN at output currents over 20A with efficiencies as high as 96%, for 12V or 24V automotive, heavy equipment, industrial control, robotics and telecom applications.

The LTC3892/-1’s adjustable 5V to 10V gate drivers enable the use of logic- or standard-level MOSFETs to maximise efficiency. It operates with a selectable fixed frequency between 50 kHz and 900 kHz, and can be synchronised to an external clock from 75 kHz to 850 kHz. The user can select from continuous operation, pulse-skipping and low ripple Burst Mode operation during light loads. The LTC3892/-1’s 2-phase operation reduces input filtering and capacitance requirements. Its current mode architecture provides easy loop compensation, fast transient response, fixed frequency operation, excellent line regulation and easy current sharing with paralleled phases for higher current. Output current sensing is accomplished by measuring the voltage drop across the output inductor (DCR) for the highest efficiency: or by using an optional sense resistor for high accuracy. Current foldback limits MOSFET heat dissipation during overload conditions. This device is available in two versions; the LTC3892 being the full-featured part with two power good signals, adjustable current limit and fixed 3.3V or 5V output voltage options.

The LTC3892 is available in a 32-lead 5 x 5 mm QFN package and the LTC3892-1 is available in a 28-lead TSSOP package. Four temperature grades are available, with operation from -40 to 125°C for the extended and industrial grades, a high temp automotive range of -40°C to 150°C and a military grade guaranteed from -55°C to 150°C. Pricing starts at $4.82 (1000).

Linear Technology; www.linear.com/product/LTC3892