Date: 29/10/2010

60V input synchronous buck DC/DC controller from Linear Tech

Linear Technology Corporation has unveiled the LTC3891, a synchronous buck DC/DC controller. The controller consumes 50µA of power in standby mode. The device features an input supply voltage range of 4V to 60V and is designed to protect against high voltage transients, continue operation during automotive cold crank and cover a broad range of input sources and battery chemistries. The output voltage can be set from 0.8V to 24V at output currents up to 20A with efficiencies of 95%. The controller is suitable for 12V, 24V or 48V automotive, heavy equipment, industrial control, robotics and telecom applications.

The LTC3891 features a 1.1Ohm on-chip MOSFET gate drivers and operates with a selectable fixed frequency between 50kHz and 900kHz. The buck controller is synchronizable to an external clock from 75kHz to 850kHz with its phase-locked loop (PLL). The user can select from continuous operation, pulse skipping and low ripple Burst Mode operation during light loads. Its current-mode architecture provides loop compensation, fast transient response and good line regulation. Output current sensing is accomplished by measuring the voltage drop across the output inductor (DCR). Current foldback limits MOSFET heat dissipation during overload conditions. The device also features a 95ns minimum on-time for high step-down ratios at high frequency, up to 99% duty cycle for low voltage drop out, an internal LDO that powers gate drivers from the input voltage or EXTVCC and a power good signal.

Operating temperature range:
Extended & Industrial Grades: -40deg C to 125deg C
Automotive Temp Grade: -40deg C to 150deg C
Military Temp Grade: -55deg C to 150deg C

Package: 20-pin 3mm x 4mm QFN and 20-lead TSSOP thermally enhanced packages.

Price: Each US$3.47 for 1K pieces.

Availability: Now