AP1605,pdf,datasheet (PWM/PFM

AP1605 consists of CMOS step-down switching
regulator with PWM/PFM dual mode control. These
devices include a reference voltage source, oscillation
circuit, error amplifier, internal PMOS and etc.
AP1605 provides low-ripple power, high efficiency,
and excellent transient characteristics. The
PWM/PFM control circuit is able to very the duty ratio
linearly 0%~0.25% (PFM) and 25%~100% (PWM).
With the addition of an internal P-channel Power MOS,
a coil, capacitors, and a diode connected externally,
these ICs can function as step-down switching
regulators. They serve as ideal power supply units for
portable devices when coupled with the SOP–8L
mini-package, providing such outstanding features as
low current consumption. Since this converter can
accommodate an input voltage of up to 7V, it is also
ideal when operating via an AC adapter.