Microwave Journal
www.microwavejournal.com/articles/18634-step-down-dcdc-controller-ltc3864

Step-Down DC/DC Controller: LTC3864

November 8, 2012

3864Linear Technology Corp. introduces the LTC3864, a high voltage step-down DC/DC controller that draws only 40 µA quiescent current in standby mode with the output enabled in Burst Mode® operation. The 3.5 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 0.8 V to VIN due to its 100% duty cycle capability, making it well suited for 12 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 50kHz and 850kHz, and is synchronizable to an external clock from 75kHz to 750kHz. 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.

Summary of Features: LTC3864

  • VIN Range from 3.5V to 60V
  • Wide VOUT Range: 0.8V to VIN
  • Low Quiescent Current 40µA in Standby mode
  • Selectable Low Ripple Burst Mode® Operation or Pulse Skipping at Light Loads
  • Selectable Fixed Operating Frequency from 50kHz to 850kHz
  • PLL Synchronizable Operating Frequency from 75kHz to 750kHz
  • Current-Mode Control for Fast Transient Response & Easy Loop Compensation
  • Adjustable Soft-Start or Tracking
  • Output Overvoltage & Overcurrent Protection
  • Power Good Output Signal
  • Extended & Industrial 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

Additional Information:

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

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