The LT3668 is a monolithic triple power supply composed of a 400mA buck switching regulator and two 200mA low dropout linear tracking regulators (LDOs).This provides a complete and robust power solution for applications that require the power supply of a sensor to tightly track the power supply of a measurement ASIC.Each tracking LDO supplies 200mA of output current with a typical dropout voltage of 340mV, and each LDO has an accurate resistor programmable current limit.Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse current protection.The buck regulator includes a high efficiency switch, a boost diode, and the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application.The LT3668 is available in a thermally-enhanced 16-lead MSOP package with exposed pad for low thermal resistance.ApplicationsFault-Protected Sensor SupplyAutomotive and Industrial SuppliesPower for Portable Instrumentation