Synchronous Step-Down DC/DC Controller: LTC3892

LTC3892 Linear Technology Corp. announces the LTC3892, a high voltage dual output synchronous step-down DC/DC controller that draws only 29 µA when one output is active and 34 µA when both outputs are enabled. The 4.5 to 60 V 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 0.8 V to 99% of V_IN at output currents over 20 amps with efficiencies as high as 96%, making it well suited for 12 or 24 V 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 maximize efficiency. It operates with a selectable fixed frequency between 50kHz and 900kHz, and can be synchronized to an external clock from 75kHz to 850kHz. 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 5mm x 5mm 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. The 1,000-piece price starts at $4.82 each. For more information, visit www.linear.com/product/LTC3892.

Summary of Features: LTC3892/-1

Wide Input Voltage Range:
4.5V to 60V
Wide Output Voltage Range:
0.8V to 0.99V_IN
29µA Quiescent Current with One Output Active & 34µA with Both Outputs Active
Adjustable 5V to 10V Gate Drive Voltage
Synchronous Rectification for up to 95% Efficiency
DCR or R_SENSE Current Sense
Selectable Low Ripple Burst Mode^® Operation, Pulse-Skipping or Continuous Operation
Selectable Fixed Operating Frequency from 50kHz to 900kHz
Phase-Lockable Frequency from 75kHz to 850kHz
Current Mode Control for Fast Transient Response & Easy Loop Compensation
Adjustable Soft-Start
Output Overvoltage & Overcurrent Foldback Protection
Extended & Industrial Temp Grades:
-40°C to 125°C Operating Junction Temp
Automotive Temp Grade:
-40°C to 150°C Operating Junction Temp
Military Temp Grade:
-55°C to 150°C Operating Junction Temp