The 5KP28A is a transient voltage suppressor (TVS) diode manufactured by Yageo. It is RoHS compliant and rated with a breakdown voltage of 45.4V, a clamping voltage of 31.1V, and an operating voltage of 28V. This diode is used to protect electronic devices from transient voltage spikes, such as those caused by lightning, power surges, and electrostatic discharge.