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Solutions Power Management Switching Regulator Step-Down (Buck) Regulators Internal Power Switch Buck
Solutions Power Management Switching Regulator Step-Down (Buck) Regulators High Input Voltage Buck
Solutions DC Regulator Solutions DC-DC Voltage Regulation Step Down DC-DC Solutions (Vin > Vout)
Solutions Power Management Switching Regulator Step-Down (Buck) Regulators Micropower Buck Regulators

DC1526A - LT3991EMSE Demo Board | 55V, 1.2A, Step-Down Regulator with 2.8uA Quiescent Current

Demonstration circuit 1526 is a monolithic stepdown DC/DC switching regulator featuring the LT®3991. The switching frequency is adjustable up to 2MHz. The demo circuit is designed for 3.3V, 1.2A output from a 4.5V to 55V input. The wide input range of the LT3991 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 15mV. 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 1.01V with 30mV of hysteresis. When Vin is above 6V, adding a resistor divider from Vin to EN can program the
LT3991 to regulate the output only when Vin is above a desired voltage. The circuit consumes only 2.8μA of quiescent current. The boost diode, control and logic circuit are integrated to reduce the components count and solution size. The current mode control scheme creates fast transient response and good loop stability.

DC1526A - Schematic

 


Software

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

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