Features

• Automatic Step-Up and Step-Down Conversion
• Uses a Single Inductor
• Wide 4V to 60V Input Voltage Range
• V_OUT from 3.3V to 20V
• Dual Internal 500mA Switches
• 100µA No-Load Quiescent Current
• Low Current Shutdown
• ±1% Output Voltage Accuracy
• 200kHz Operating Frequency
• Boosted Supply Pin to Saturate High Side Switch
• Frequency Foldback Protection
• Current Limit Foldback Protection
• Current Limit Unaffected by Duty Cycle
• 16-lead Thermally Enhanced TSSOP Package

Typical Application

Description

The LT3433 is a 200kHz fixed-frequency current mode switching regulator that provides both step-up and stepdown regulation using a single inductor. The IC operates over a 4V to 60V input voltage range making it suitable for use in various wide input voltage range applications such as automotive electronics that must withstand both load dump and cold crank conditions.

Internal control circuitry monitors system conditions and converts from single switch buck operation to dual switch bridged operation when required, seamlessly changing between step-down and step-up voltage conversion.

Optional Burst Mode operation reduces no-load quiescent current to 100µA and maintains high efficiencies with light loads.

Current limit foldback and frequency foldback help prevent inductor current runaway during start-up. Programmable soft-start helps prevent output overshoot at start-up.

The LT3433 is available in a 16-lead thermally enhanced TSSOP package.