OptiMOS™ IPOL 40 A single-voltage stackable synchronous buck regulator TDA38540 40 A DC-DC buck regulator features an onboard PWM controller and OptiMOS™ 5 FETs resulting in a very efficient, easy-to-use, compact VR solution. It enables stacking (up to 4) and can optionally sync to an external clock signal. TDA38540 provides extensive protection features such as pre-bias start up, UVP, OVP, etc. to give required system-level security in the event of fault conditions.