Analog Devices LT8646S

Description

The LT®8645S synchronous step-down regulator featuressecond generation Silent Switcher architecture designedto minimize EMI/EMC emissions while delivering high efficiencyat high switching frequencies. This includes theintegration of bypass capacitors to optimize all the fastcurrent loops inside and make it easy to achieve advertisedEMI performance by eliminating layout sensitivity. Thisperformance makes the LT8645S ideal for noise sensitiveapplications and environments.The fast, clean, low-overshoot switching edges enable highefficiency operation even at high switching frequencies,leading to a small overall solution size. Peak current modecontrol with a 40ns minimum on-time allows high stepdown ratios even at high switching frequencies.Burst Mode operation enables ultralow standby currentconsumption, pulse-skipping mode allows full switchingfrequency at lower output loads, or spread spectrum operationcan further reduce EMI/EMC emissions. Soft-startand tracking functionality is accessed via the TR/SS pin,and an accurate input voltage UVLO threshold can be setusing the EN/UV pin. A CLKOUT pin enables synchronizingother regulators to the LT8645S.

Features

FeaturesSilent Switcher® 2 ArchitectureUltralow EMI/EMC Emissions on Any PCBEliminates PCB Layout SensitivityInternal Bypass Capacitors Reduce Radiated EMIOptional Spread Spectrum ModulationHigh Efficiency at High FrequencyUp to 95% Efficiency at 1MHz, 12VIN to 5VOUTUp to 94% Efficiency at 2MHz, 12VIN to 5VOUTWide Input Voltage Range: 3.4V to 65VUltralow Quiescent Current Burst Mode® Operation2.5μA IQ Regulating 12VIN to 3.3VOUTOutput Ripple < 10mVP-PFast Minimum Switch On-Time: 40nsLow Dropout Under All Conditions: 60mV at 1ASafely Tolerates Inductor Saturation in OverloadAdjustable and Synchronizable: 200kHz to 2.2MHzPeak Current Mode OperationOutput Soft-Start and TrackingSmall 32-Lead 6mm × 4mm LQFN Package

More information

• Datasheet