Fine-pitch burn-in socket takes larger devices

Sockets use compression mount technology, in which the flexible contacts are pressed onto the contact pads of the PCB by screwing the socket to the board.

New from Yamaichi Electronics, the NP481 is a test and burn-in socket for large-sized ultra-fine-pitch devices.

The new socket is a development from the NP437, launched two years ago.

The high-precision 0.4mm ultra-fine-pitch contact system places high demands on the quality and reliability of the contacts, and Yamaichi reckons its sophisticated new electromechanical design answers both these criteria.

The new sockets use compression mount technology (CMT), in which the flexible contacts are pressed onto the contact pads of the PCB by screwing the socket to the board.

Yamaichi has decades of experience with CMT in the test and burn-in sector.

However, with a pitch of 0.4mm there is so little space available that a "fan-out" using an auxiliary PCB (interposer) is normally necessary to ensure continuity in burn-in boards.

This can have a negative effect on both electrical performance and costs.

Yamaichi answers this challenge by routing within the socket, achieving a PCB footprint of 0.4 x 0.6mm.

The IC solder balls are contacted using a space-saving buckling beam, which also possesses excellent mechanical load qualities.

Possible effects of the larger pin length on the electrical characteristics are negligible, as the semiconductor devices to be contacted operate in the low current range and the burn-in is carried out at low frequencies.

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