The NCP1530 is a PWM/PFM non-synchronous step-down (Buck) DC-DC converter for usage in systems supplied from 1-cell Li-ion, or 2 or more cells Alkaline/NiCd/NiMH batteries. It can operate in Constant-Frequency PWM mode or PWM/PFM mode in which the controller will automatically switch to PFM mode operation at low output loads to maintain high efficiency. The switching frequency can also be synchronized to external clock between 600 kHz and 1.2 MHz. The maximum output current is up to 600 mA. Applying an external synchronizing signal to SYN pin can supersede the PFM operation. The NCP1530 consumes only 47 mA (typ) of supply current (VOUT = 3.0 V, no switching) and can be forced to shutdown mode by bringing the enable input (EN) low. In shutdown mode, the regulator is disabled and the shutdown supply current is reduced to 0.5 mA (typ). Other features include built-in undervoltage lockout, internal thermal shutdown, an externally programmable soft-start time and output current limit protection. The NCP1530 operates from a maximum input voltage of 5.0 V and is available in a space saving, low profile Micro8TM package.