Overview

The STK740-441 is a separate-excitation step-down chopper regulator hybrid IC for the secondstage circuit and optimal as a 3.3V local power supply for use in logic circuit that includes both 5V and 3.3V systems. This IC incorporates in the package all the necessary circuits for a chopper regulator including power switch, error amplifier, soft start, shutdown type output short protection, low-voltage malfunction prevention, on/off, and snubber circuits. Therefore, external components required are input and output capacitors and choke coil only and this allows this IC to be used to construct a large-current (5A) chopper regulator as if a 3-pin regulator were used.

Features

• Adoption of Sanyo IMST ; Insulated Metal Substrate Technology, allows the circuit to be operated without using a heat sink (see “No Fin Output Current Derating” chart in the page 6).

• Slim package reduces mounting space.

• Typical efficiency of 88 at DC 5V input, 2.5A output.

• Fine adjustment of output voltage enable.

• 50 kHz operating frequency.

• Low-RON resistance power MOSFET adopted.

• Low-VF Schottky barrier diode adopted.

Applications

• 3.3V local power supply for the logic circuit where both 5V and 3.3V systems are constructed togeter.