Making acquisitions just to gain market share often fails with technical companies. Trying to merge the product lines and corporate cultures is often impossible, so the weaker (or sometimes stronger) product lines lose support -- resulting in lost market share -- and your best people get fed up with the new corporate culture and go elsewhere, weakening future prospects.
My favorite example of a merger disaster is the Daisy/Cadnetix (Dazix) merger in 1988 which resulted in Chapter 11 in 1990.
OTOH, Maxim/Dallas and TI/National seem to be going OK.
When you're a big enough company that you can pull it off and you have market share to protect, acquisitions make sense. But that's no substitute for putting valuable R and D dollars on the line to stay ahead of the curb with in-house products and designs.