ON Semiconductor Corp., one of the Valley's cornerstone technology companies, intends to terminate 475 employees across its global footprint as it grapples with the financial fallout from the COVID-19 pandemic. The plans were revealed Thursday in a regulatory filing after the markets had closed. The layoffs equate to about 1.4% of the company's global workforce of 34,800 employees, of which 4,600 worked in the U.S.