DESCRIPTION

The UTC  UD36061 is a high frequency (2MHz) step-down

switching regulator with integrated internal high-side high voltage

power MOSFET. It regulates input voltages from 3.3V to 36V down

to an output voltage as low as 0.8V, and supplies 0.6A highly

efficient output with current mode control for fast loop response.

In shutdown mode the supply current drops to 3μA, it allows

use in battery-powered applications.

High power conversion efficiency over a wide load range is

achieved by scaling down the switching frequency at light load

condition to reduce the switching and gate driving losses.

The converter uses internal N-Channel MOSFET switches to

step-down the input voltage to the regulated output voltage. Since

the high side MOSFET requires a gate voltage greater than the

input voltage, a boost capacitor connected between SW and BST is

needed to drive the high side gate. The boost capacitor is charged

from the internal 5V rail when SW is low.

Frequency fold-back helps prevent inductor current runaway

during start-up. Thermal shutdown provides reliable, fault-tolerant

operation.

FEATURES

* Wide 3.3V ~ 36V Operating Input Range

* 500mΩ Internal Power MOSFETs

* 230μA Operating Quiescent Current

* > 90% Efficiency

* 2MHz Fixed Switching Frequency

* Internally Compensated

* Internal Soft-Start

* Adjustable Output Voltage from 0.8V to 0.8×VIN

* Precision Current Limit Without Current Sensing Resistor

* Stable with Ceramic Output Capacitors

* 3μA Low Shutdown Supply Current