DESCRIPTION

The LT®8640 step-down regulator features Silent Switcher architecture designed to minimize EMI/EMC emissions while delivering high efficiency at frequencies up to3MHz. Assembled in a3mm ×4mm QFN, the monolithic construction with integrated power switches and inclusion of all
necessary circuitry yields a solution with a minimal PCB footprint. An ultralow2.5µA 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 below10mVP-P at any load, from zero to full current.

FEATURES

Silent Switcher® Architecture
Ultralow EMI/EMC Emissions
Spread Spectrum Frequency Modulation
High Efficiency at High Frequency
Up to 96% Efficiency at 1MHz
Up to 95% Efficiency at 2MHz
Wide Input Voltage Range: 3.4V to 42V
5A Maximum Continuous Output, 7A Peak Transient Output
Ultralow Quiescent Current Burst Mode® Operation
2.5μA IQRegulating 12VINto 3.3VOUT
Output Ripple < 10mVP-P
Fast Minimum Switch-On Time: 40ns
Low Dropout Under All Conditions: 100mV at 1A
Safely Tolerates Inductor Saturation in Overload
Adjustable and Synchronizable: 200kHz to 3MHz
Peak Current Mode Operation
Output Soft-Start and Tracking
Small 18-Lead 3mm ×4mm QFN

APPLICATIONS

Automotive and Industrial Supplies
General Purpose Step-Down
GSM Power Supplies