UPDATE 1-Maxim Integrated to buy Teridian for $315 mln

* Says deal to immediately add to earnings

April 12 (Reuters) - Chipmaker Maxim Integrated Products Inc MXIM.O said it would buy privately held Teridian Semiconductor Corp for $315 million in cash to expand its presence in the smart meter market.

The deal would help Maxim accelerate sales of its existing power management, real-time clock, and interface products, and security IP, which are all required in smart meters, the company said.

Irvine, California-based Teridian is a fabless mixed-signal chipmaker focused on electricity metering and energy measurement for the smart grid.

Maxim Integrated, which competes with Analog Devices Inc ADI.N, National Semiconductor Corp NSM.N and Texas Instruments Inc TXN.N, makes analog and mixed-signal chips for automotive, communications, consumer electronics and computing and storage markets.

The deal will add to earnings immediately, excluding acquisition-related charges and amortization, Maxim said.

Smart meter units using both system-on-chip and multi-chip solutions are estimated to grow 10 percent annually through 2014, Maxim said, adding, Teridian has 50 percent share in the system-on-chip energy measurement market.

Maxim shares were up a percent at $20.12 in after-market trade. They closed at $19.89 Monday on Nasdaq. (Reporting by Mansi Dutta in Bangalore; Editing by Ratul Ray Chaudhuri)