The AP1507 is a monolithic IC designed for a step-down DC/DC converter and is capable of driving a 3A load without an external transistor. Due to reducing the number of external components, the board space can be saved easily. The external shutdown function can be controlled by logic level and then come into standby mode. The internal compensation makes the feedback control have good line and load regulation without an external design. Regarding the protected function, the thermal shutdown is to prevent over temperature operating from damaging the device, and current limit is against over current operating of the output switch. If the current limit function occurred and VFB is down to 0.5V below, the switching frequency will be reduced. The AP1507 series operates at a switching frequency of 150KHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Other features include a guaranteed +4% tolerance on output voltage under specified input voltage and output load conditions, and +15% on the oscillator frequency. The output version included a fixed 3.3V, 5V, 12V, and an adjustable type. AP1507 is available in a 5-lead TO-252 lead-free package.