R1276S Synchronous Step-Down DC-DC Converter Nisshinbo R1276S Synchronous Step-Down DC-DC Converter features a built-in transistor and 95% efficiency. Under cranking conditions, the switching frequency of the R1276S is automatically reduced to keep the output voltage level constant. The R1276S DC-DC Converter has a 3.6V to 30.0V input voltage range and a 4.5V start-up voltage. The typical standby current is 4µA. The R1276S ensures low EMI (Electromagnetic Interference) noise by employing a spread spectrum clock generator with a +10% diffusion rate.