Atmel Corp.'s board said an unsolicited bid from Microchip Technology Inc. is a "superior proposal" to the terms of the merger agreement it had signed with Dialog Semiconductor Plc last year. The binding offer from Microchip is for $8.15 a share, with $7 in cash and a fraction of a share of Microchip common stock valued at $1.15 based on a 10-day average closing price, Atmel said in a statement Wednesday.