Buck regulator operates from fluctuating input supplies

Article By : Susan Nordyk

To enhance efficiency at light loads, the LTM8053 automatically switches to Burst Mode operation, which keeps the output capacitor charged to the proper voltage.

Able to accommodate an input voltage of up to 40V, the LTM8053 µModule step-down regulator from Linear Technology safely operates from unregulated or fluctuating 12V to 36V input supplies for use in industrial robotics, factory automation, and avionics systems.

The module integrates a switching regulator controller, power switches, inductor, and other supporting components in a 6.25mm × 9mm × 3.32mm BGA package. Only two capacitors and two resistors are needed to complete the design.

__Figure 1:__ *The LTM8053 needs only two capacitors and two resistors to complete the design.*

The regulator delivers 3.5A of continuous output current (6A peak). Output voltage is adjustable with a single resistor from 0.97V to 15V, enabling the part to generate common system bus voltages, including 3.3V, 5V, 12V, and 15V. Efficiency at 12VIN to 5VOUT is 90%, and switching frequency is selectable from 200kHz to 3MHz.

A share pin allows two or more regulators to be paralleled for applications that require higher current. To enhance efficiency at light loads, the LTM8053 automatically switches to Burst Mode operation, which keeps the output capacitor charged to the proper voltage, while minimising the input quiescent current.

__Figure 2:__ *Typical application (Source: Linear)*

Prices for the LTM8053 start at $9.66 each in lots of 1,000 units.

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