National Semiconductor Corporation introduced a dual op amp encased by a revolutionary new packaging process that leaves the final product only slightly larger than the die itself. The LMC6035IBP, a general-purpose dual op amp optimized for low power applications, is just 1.45mm square. Its leadless Micro-SMD package is applied to the die entirely at the wafer level using a patented encapsulation process on the front and back of the wafer. Standardized JEDEC "bump" pads with 0.5mm pitch assure circuit board placement accuracy using existing passive component assembly chip shooter mounting equipment. The device's 0.90mm height easily meets the requirements of all PCMCIA and other height-sensitive applications.

"This time we may have reached the packaging limits with the smallest possible footprint, short of turning the device on its side," said Ed Lam, Director of National's Standard Analog Products. "At half the footprint of National's earlier announced LMV series of op amps in SC70 packages, the Micro-SMD clearly marks National as the industry leader in packaging technology," he added.

National's Micro-SMD package has a number of advantages over traditional leaded plastic packages. They include the smallest footprint possible for commercially available 8-I/O packages, superior electrical characteristics, easy board assembly and level 1 moisture sensitivity performance. The Micro-SMD package's small size and shorter interconnections also result in low inductance and minimal signal degradation. A series of reliability tests was conducted, including thermal cycles, solder joint integrity, ESD and drop tests, with no package failures reported.

Since the Micro-SMD package complies with the JEDEC registered outline MO-211, it can be handled and applied to circuit boards with standard pick and place machines and with no need for special vision systems. Standard IR eutectic reflow techniques are used to attach the self-aligning bumps. An added benefit of the Micro-SMD package is that underfilling is not required, further simplifying the assembly process, reducing cost and making it possible to rework the board.

No, this isn't the "best" op amp ever made in terms of its specifications, although it is an extremely good general purpose, low-voltage, rail-to-rail dual; and the product would probably not have made it this page just from the specifications, but that's not the story here. The story is the packaging -- or better put, the lack of packaging. Compared with all the other miniature solutions that I have seen coming along in the chip scale/flip chip areas of development, this solution from National is a return to surface mount with standard JEDEC bumps. The product can be handled with existing production equipment and as Ed Lam noted in the release they may have reached the limits of size "short of turning the device on its size." Maybe they are thinking of that! But that is unlikely, I think, because they would have to create a non-standard bump specification which would be difficult for the industry to accept, or pay for.

The production of the parts, complete with the protective layers and bumps is totally a wafer fabrication process. Silicon does not have to be cut and then mounted in something else, a package; the finished product leaves the fab.