NEW YORK – General Atlantic and Francisco Partners, major private equity firms, have sued Aeroflex Inc., saying the maker of electronics test equipment owes them a larger fee for breaking off a pending merger.

According to an SEC filing, the $22.5 million breakup Aeroflex agreed to pay was some $15 million less than GA and Francisco claim they are owed.

In May, Aeroflex accepted a higher bid from another private equity group: Veritas Capital. 

GA and Francisco contend they are owed $30 million in termination fees, plus reimbursement of $7.5 million in expenses. Aeroflex counters that the amount includes a $15 million termination fee plus $7.5 million in expenses. GA and Francisco also seek plus pre-judgment and post-judgment interest and costs and expenses, including attorneys' fees.

No date for trial has been set. Aeroflex says it believes the allegations are without merit, and it intends to defend against them vigorously.