Conforming to SEMI F47 Voltage Sag Tolerance

Power supplies used in semiconductor manufacturing equipment are generally required to conform to the SEMI F47-0706 voltage sag tolerance standard. These standard details the conditions under which a power supply must continue to operate in the event of a temporary degradation of its single-phase AC input voltage level. (SEMI F47 does not apply to three-phase input power supplies.)

As shown in the table below, the SEMI F47 standard defines three levels of AC voltage degradation, and duration times over which the power supply must continue to operate:

• 80% sag (a 20% reduction in the AC level): 1 second
• 70% sag (a 30% reduction in the AC level): 0.5 seconds
• 50% sag (a 50% reduction in the AC level): 0.2 seconds

Spec: SEMI F47-0706, Revised 2006

The continued operation of a power supply under-voltage sag conditions is qualified to different levels of performance, ranging from full performance operation to a loss of output. Power supplies that accept “universal” AC input ranges of 100-240 VAC will generally continue to deliver full performance operation under all three voltage sag conditions for so-called “high line” systems. The most common single-phase high line voltages are 208, 230, and 240 VAC.

AstrodyneTDI Solutions

Astrodyne TDI’s ASM family of universal input power supplies can meet almost any need for high line semiconductor manufacturing equipment.   Delivering output powers from 30 Watts to 550 Watts, with combinations of products that can support even higher power levels, each series in the family is optimized to provide the smallest footprint for its rated power level. The ASM product family offers models with a variety of connector and enclosure options and delivers full performance operation under the SEMI F47 voltage sag standard for high line systems.