42V, 3.5A (IOUT), 2.2MHz Synchronous Step-Down DC/DC Converter Delivers 96% Efficiency & Needs Only 2.5µA of Quiescent Current

Linear Technology LT8610A LT8610AB

Linear Technology Corporation announces the LT8610A and LT8610AB. Both are 3.5 A, 42 V input capable synchronous step-down switching regulators. Synchronous rectification delivers efficiency as high as 96% while Burst Mode operation keeps quiescent current under 2.5 µA in no-load standby conditions. Their 3.4 V to 42 V input voltage range makes them ideal for automotive and industrial applications. The internal 5 A switches can deliver up to 3.5 A of continuous output current to voltages as low as 0.97 V. The LT8610A/ABs’s Burst Mode operation offers ultralow quiescent current, making it well suited for applications such as automotive “always-on” systems, which is needed to extend operating battery life. The LT8610A/AB’s unique design maintains a minimum dropout voltage of only 200 mV at 1 A under all conditions, enabling it to excel in scenarios such as automotive cold-crank. Furthermore, a fast minimum on-time of only 30 ns enables 2 MHz constant frequency switching from a 16 V input to a 1.0 V output, so designers can optimize efficiency while avoiding critical noise-sensitive frequency bands. The LT8610A/AB’s 16-lead thermally enhanced MSOP package and high switching frequency keeps external inductors and capacitors small, providing a compact thermally efficient footprint. The LT8610AB offers higher efficiency at very light loads <0.5 mA when compared to the LT8610A, but this does result in slightly higher output ripple.

Linear Technology - LT8610A, LT8610AB

The LT8610A and LT8610AB share all of the performance and features of the LT8610 with the following improvements. First, they deliver 3.5 A of continuous output current, in lieu of the LT8610’s 2.5 A capability. Secondly, their minimum on-time has been reduced from 50ns to 30ns, enabling 16 V to 1 V step-down conversion @ 2 MHz, compared to 1.8 V for the standard LT8610. All other electrical parameters are identical to the standard LT8610.

The LT8610AEMSE and LT8610ABEMSE are packaged in thermally enhanced MSOP-16 packages and are priced starting at $3.75 each. An industrial temperature version, the LT8610AIMSE and LT8610ABIMSE are tested and guaranteed to operate from a -40 °C to 125 °C operating junction temperature and are priced starting at $4.13 each. Automotive temperature versions, the LT8610AHMSE and LT8610ABHMSE are tested and guaranteed to operate from a -40 °C to 150 °C operating junction temperature and are priced starting at $4.38 each. All pricing is for 1,000-piece quantities and all versions are available from stock.

Summary of Features:

  • Wide Input Voltage Range:
  • 3.4 V to 42 V
  • Up to 3.5 A of Continuous Output Current
  • Ultralow Quiescent Current Burst Mode® Operation
  • 2.5 µA IQ Regulating 12 VIN to 3.3 VOUT
  • Output Ripple < 10 mVP-P (LT8610A Only)
  • High Efficiency Synchronous Operation:
    • 96% Efficiency at 1A, 5 VOUT from 12 VIN
    • 94% Efficiency at 1A, 3.3 VOUT from 12 VIN
  • Fast Minimum Switch-On Time: 30 ns
  • Low Dropout under All Conditions:200 mV at 1 A
  • Allows Use of Small Inductors
  • Adjustable & Synchronizable:200 kHz to 2.2 MHz
  • Current-Mode Operation
  • Accurate 1 V Enable Pin Threshold
  • Internal Compensation
  • Output Soft-Start & Tracking
  • Small Thermally Enhanced 16-Lead MSOP Package

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