The RP506K Series are low supply current CMOS-based PWM/VFM step-down DC/ DC converters with synchronous rectifier featuring 2A*1 output current. Internally, a single IC consists of an oscillator, a reference voltage unit, an error amplifier, a switching control circuit, a mode control circuit, a soft start circuit, a latch protection circuit, an under-voltage lockout (UVLO) circuit, a thermal shutdown circuit, and switching transistors. By simply using an inductor and capacitors as external components, without connecting any diode, a low ripple and high efficiency synchronous rectifier step-down DC/ DC converter can be easily configured. RP506K is available in DFN(PLP)2527-10 package which achieves high-density mounting on boards. RP506K is available in the fixed output voltage type (RP506Kxx1A/ B/ D/ E) which can be set by 0.1 V step and the output voltage accuracy is as high as ±1.5% or ±18mV, or the adjustable output voltage type (RP506K001C/ F) which can be set by using the external resistors. The oscillator frequency can be selected from 2.25MHz (RP506Kxx1A/ B/ C) or 1.2MHz (RP506K001C/ F). By inputting a signal to MODE pin, RP506K can choose PWM/VFM auto switching control or forced PWM control. In low output current, PWM/VFM auto switching control automatically switches from PWM mode to VFM mode in order to achieve high efficiency.