Synopsys, a key Silicon Valley supplier to the chip industry, said on Tuesday that it had agreed to pay $35 billion for Ansys, a Pennsylvania company that makes software used to simulate and analyze product designs for electronics manufacturers, car makers, defense contractors and others.

The deal, which was struck for a combination of cash and stock, follows a $14 billion deal this month by Hewlett Packard Enterprise to buy Juniper Networks, uniting a big computer maker with a specialist in networking gear. It was the latest sign of changing times in the technology sector, which is experiencing slow sales for many types of hardware and a frenzy over artificial intelligence.

A.I. has prompted heavy spending in data centers and has also led many giant internet companies to start designing their own chips. Some carmakers, which have become a major new source of chip demand amid pressures to electrify more vehicles and add driver-assistance features, are also designing their own chips.

Synopsys is a pioneer in software that simulates and verifies chip designs, gradually adding products to help design more complete electronic systems. It has worked with Ansys since 2017 to win more customers for such tasks.