San Jose, CA--Cell phones that slip into a shirt pocket. Wireless data PCMCIA cards the size of a Visa card. The name of the game today is increased functionality in ever-decreasing form factors, and Hewlett Packard is one of the companies leading the way with innovations in electronics packaging.
Three years ago, HP was the first company to put a family of high-performance amplifiers into a tiny SOT-363 package--the six-lead version of the SC-70. The Lilliputian package measures a mere 0.087 inch square (from the tip of the leads), lead spacing is a minuscule 25 mils.
In the interim, HP has introduced GAAS amplifiers and mixers, silicon bipolar transistors, GaAS PHEMT FETS, and PIN and Schottky diodes--all in the same tiny package. Its latest offering is a family of smaller packaged transistors. "Our focus is on providing more functionality per PC board area," says Gary Carr, business development manager.
A tough charter. But HP engineers have been able to effectively achieve board space reductions of between 20 and 75% on the devices mentioned above by concentrating on three areas: higher levels of integration, clever grouping or layout of devices, and reduction in die sizes.
With less real estate to dissipate the heat, thermal management is typically the design engineer's worst nightmare. But Carr explains that the new packaging actually gave engineers a bit of a break. "In the traditional package, the lead frame--which dissipates most of the heat--was made out of a copper alloy. The new SO-363 has copper leads, with better heat transfer characteristics."
While the SC-70 packages are now common in cell phones, the small packages can pose problems for design engineers unfamiliar with them. So to assist customers in their own prototyping efforts, HP has designed application demonstration boards for most of the SC-70 products.
For the near term, Carr says there probably won't be the drastic reductions in package size seen in the past. "With any technology, you follow the curve until you get to diminishing returns. I'm not going to say that packages will not become any smaller. But we may be limited by our ability to make the die much smaller."
For more information on HP products, visit the company's website at www.hp.com/go/rf