The TS2507 integrates Pulse- Width-Modulation ( PW M) control circuit into a s ingle chip. These devise include a reference voltage source, oscillation circuit, error amplifier and etc. TS2507 pr ovides low-ripple power, high efficiency, and excellent transient characteris tics. The PW M control c ircuit is able to very the duty ratio linearly for m 0 up to 100%. This controller also contains an error amplifier circuit as well as a soft-s tart circuit that prevents over shoot at startup. An enable function, an over current protect function and shor t circuit protect func tion are built inside, and when OC P or SC P happens , the operation frequency will be r educed. Also, an internal compensation block is built in to minimum external component count. With the addition of an ex ternal P-channel Power MOS, a coil, capacitors, and a diode connec ted externally , these components can function as step-down switching regulators. They serve as ideal power supply units for portable devices w hen coupled with the SOP-8, providing such outstanding features as low current consumption. Since this converter can accommodate an input