65V, 3.5A/5A Peak Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current

The LT8641A step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at frequencies up to 3MHz. Assembled in a 3mm × 4mm side wettable QFN, the monolithic construction with integrated power switches and inclusion of all necessary circuitry yields a solution with a minimal PCB footprint. An ultralow 2.5μA quiescent current — with the output in full regulation — enables applications requiring highest efficiency at very small load currents. Transient response remains excellent and output voltage ripple is below 10mVP-P at any load, from zero to full current.

The LT8641A allows high VIN to low VOUT conversion at high frequency with a fast minimum top switch on-time of 35ns. Operation is safe in overload even with a saturated inductor.

Essential features are included and easy to use: an open-drain PG pin signals when the output is in regulation. The SYNC/MODE pin selects between Burst Mode, pulse-skipping, or spread spectrum mode, and also allows synchronization to an external clock. Soft-start and tracking functionality are accessed through the TR/SS pin. An accurate enable threshold can be set using the EN/UV pin and a resistor at the RT pin programs switch frequency.

APPLICATIONS

* Automotive and Industrial Supplies

* General Purpose Step-Down

* Silent Switcher® Architecture

* Ultralow EMI Emissions

* Spread Spectrum Frequency Modulation

* High Efficiency at High Frequency

* Up to 95% Efficiency at 1MHz, 12VIN to 5VOUT

* Up to 94% Efficiency at 2MHz, 12VIN to 5VOUT

* Wide Input Voltage Range: 3V to 65V

* 3.5A Maximum Continuous, 5A Peak Transient Output

* Ultralow Quiescent Current Burst Mode® Operation

* 2.5μA IQ Regulating 12VIN to 3.3VOUT

* Output Ripple < 10mVP-P