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Low quiescent current synchronous step-down DC/DC controller offers high reliability performance

Linear Technology Corporation has introduced a new high reliability (MP) grade version of the LT3845, a 4 V to 60 V input voltage range, low quiescent current synchronous step-down DC/DC controller.

The device's Burst Mode operation keeps quiescent current under 120 μA in no load standby conditions, useful for extending run time in battery-powered applications. The device's powerful onboard N-channel MOSFET gate drivers provide output current up to 20 amps at efficiencies as high as 95 percent, making it ideal for 12 V and 24 V automotive systems, industrial controls, heavy equipment, avionics and military systems.

The LT3845 can produce an output voltage from 1.23 V to 36 V. The switching frequency is programmable from 100 kHz to 500 kHz or can be synchronized to an external clock up to 600 kHz. Current mode control provides fast line and load transient response, as well as cycle-by-cycle overcurrent protection. The onboard regulator provides IC power directly from the input supply without the need for a separate bias voltage. Other features include short-circuit protection, adjustable soft-start, thermal shutdown and precision input undervoltage lockout. The LT3845 employs adaptive nonoverlap control, which maintains a constant dead time, preventing shoot-through switch currents, independent of the type, size or operating conditions of the external MOSFET switches.

Summary of Features: LT3845

  • Wide 4 V to 60 V Input Voltage Range
  • Low 120 μA Quiescent Current Extends Battery
  • Run Time
  • Output Voltages from 1.23 V to 36 V
  • Up to 95 percent Efficiency
  • Onboard N-Channel MOSFET Gate Drivers
  • Integrated Onboard Regulator for IC Bias Voltage
  • Current Mode Control
  • Programmable Fixed Frequency from 100 kHz to 500 kHz
  • Synchronizable up to 600 kHz
  • Adjustable Soft Start
  • Adaptive Nonoverlap Circuitry Prevents Switch

  • Shoot-Through

The LT3845MP operates and is 100 percent tested over a junction temperature range of -55 to 125 degrees C, compared to the I grade version's -40 to 125 degrees C operating temperature range. It is offered in 16-lead thermally enhanced TSSOP package. 1,000-piece price starts at $10.65 each.

Datasheet:

LT3845MP

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