ANALOG DEVICES DC1471A Demonstration Board, LT3990EMSE, Step Down Switching Regulator

DC1471A demonstration circuit is a monolithic step-down DC/DC switching regulator featuring the LT3990. The switching frequency is adjustable up to 2.2MHz. The demo circuit is designed for 5V, 350mA output from a 6.5V to 62V input. The wide input range of the LT3990 allows a variety of input sources including automotive batteries and 24V industrial supplies. Low ripple Burst Mode increases the efficiency at the light load while keeping the output ripple below 5mV in a typical application. The part is in shutdown when the EN pin is low and active when the pin is high. The threshold of the EN pin is accurate at 1V when Vin is above 4.2V. Adding a resistor divider from Vin to EN can program the LT3990 to regulate the output only when Vin is above a desired voltage. The catch diode and boost diode are integrated to reduce the component count and solution size. The circuit consumes only 2.5µA of quiescent current.

Notes

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