The LT3942 is a monolithic 4-switch synchronous buck-boost converter with constant voltage and constant current regulation, suitable for both voltage regulator and LED driver applications. The part can regulate the output voltage, or input/output current with input voltages above, below, or equal to the output voltage. The proprietary peak-buck peak-boost current mode control scheme allows adjustable and synchronizable 300kHz to 2MHz fixed frequency operation, or internal 25% triangle spread spectrum operation for low EMI. The LT3942 covers 3V to 36V input and 0V to 36V output with seamless low-noise mode transition.For voltage regulator applications, the LT3942 provides input or output current monitor. For LED driver applications, it provides current regulation with up to 128:1 internal and 5000:1 external PWM dimming using an optional high-side PMOS switch. Fault protection is also provided to detect output short-circuit condition and open or short LED condition.ApplicationsVoltage Regulator with Accurate Current LimitGeneral Purpose LED DriverAutomotive and Industrial Lighting