MCR01MZPF3921 is an ultra-small surface mount voltage regulator diode made by ROHM Semiconductor. It has a maximum operating current of 150mA, a maximum voltage of 16V, and a low reverse current of 200nA. The diode is often used in automotive, industrial, and consumer applications that require a reliable and compact device. The device is particularly suited for applications requiring a compact, yet power management efficient voltage regulator.