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New Generation of High Pin-Count Integrated Circuit Packages

Continuing decades of packaging innovation, National Semiconductor announced the release of the micro SMDxt (micro Surface Mount Device extended technology) chip package, the company's newest generation of wafer-level package technologies. In separate announcements, National launched two new Boomer audio amplifiers - the first products that use micro SMDxt packages to reduce board space by as much as 70 percent.

The new package, which builds on National's highly successful micro SMD, uses a unique structure that enables high-reliability products with bump counts of 42 to 100 bumps at a 0.5 mm pitch without any underfill. Higher bump-count packages enable designers to create more complex products with advanced features and pack them into a smaller space. (Pitch is the distance between bumps. First-generation micro SMD products featured packages with bump counts up to 36 and pitch of 0.5 mm).

The superior electrical noise performance of this package (compared to standard wire-bonded devices) makes it well-suited for high-performance mobile applications. Thermal performance of micro SMDxt packages is comparable to other thermally enhanced packages such as QFN or Leadless Lead Frame (LLP) packages with similar pin count. Reliability standards such as thermal cycling, thermal shock, and drop test, and flex test can be met without the use of an underfill.

The first product that uses the innovative package is the LM4934 Boomer stereo audio subsystem in the 42-bump micro SMDxt. National also introduced the LM4935, a new complete Boomer audio subsystem with a mono Class D speaker driver. Packaged in a 49-bump micro SMDxt, the new LM4935 requires 70 percent less board space than existing solutions.

- The die is the package - smallest possible size for a given I/O count at 0.5 mm pitch
- 0.65 mm package height - enables integration into thin-profile consumer products
- Patented epoxy back-coating - protects against silicon damage during manufacturing
- Self-aligning solder bumps simplify surface mount assembly and rework
- Uses standard surface mount equipment and flow
- Available in standard 8 mm and 12 mm EIA tape-and-reel format
- Moisture sensitivity level-1 (MSL-1) compliant
- Passes all standard reliability tests: OPL, Temperature Humidity Bias Test (THBT), Temp Cycle, Autoclave and ESD
- Passes all board-level reliability tests: drop, thermal cycling and flex.



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