SEMI, the industry association for the semiconductor industry, has developed the SEMI F47 voltage sag immunity standard. Information about SEMI F47 – The Voltage Sag Immunity Standard.
SEMI F47 sets out the required voltage sag tolerance for semiconductor fab equipment
SEMI F47 suggests that semiconductor manufacturers may use this sag standard whenever they purchase equipment. Major semiconductor manufacturers require compliance, including Texas Instruments, Freescale, IBM, and others.
SEMI F47 says that you must use IEC 61000-4-34 (an international standard that PSL helped to write) to test compliance. It describes safety procedures, processing modes, test sequences, phase connections, test equipment, and reporting requirements. PSL’s sag generators are designed specifically to test according to SEMI F47 and IEC 61000-4-34.
In essence, SEMI F47 requires that semiconductor processing equipment tolerate voltage sags on their ac power line. Specifically, they must tolerate sags to 50% for up to 200 ms, sags to 70% for up to 0.5 seconds, and sags to 80% for up to one second. In addition to these requirements, SEMI F47 recommends that equipment tolerate sags to 0% for one cycle, sags to 80% for 10 seconds, and continuous sags to 90%, but these are not part of the requirements.
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