Here's a quick quiz for everyone connected with the next generation 3G cellular phone: what are the most critical parts in the new handset?Reminiscent of "for want of a horseshoe nail, a kingdom was lost," the absolutely critical parts are the lowly, mundane penny-cost passive components. And this is never more true than with the leading edge 3G handset with all its gee-whiz electronics.
Here's a quick quiz for everyone connected with the next generation 3G cellular phone: what are the most critical parts in the new handset?
Chances are you'll guess wrong. And the answer could be of more than academic interest.
The quintessenial parts that everyone takes for granted determine whether the phone works at all, or comes back into the channel in a recall or rejection.
No, the key part isn't the advanced custom ASIC or embedded DSP. It isn't a single chip RF. It isn't application specific SDRAMs.
Reminiscent of "for want of a horseshoe nail, a kingdom was lost," the absolutely critical parts are the lowly, mundane penny-cost passive components. And this is never more true than with the leading edge 3G handset with all its gee-whiz electronics.
Ask any OEM design engineer laying out the complex 8-layer interconnection board to cram PC-power and mini-color LCD screen into no more space than current cell phones.
If they're honest, they'll tell you that without throw-away-priced filters, capacitors, resistors and inductors, your state-of-the-art 3G phone gets only dead air.
In fact, there's even greater numbers of the ignoble passives in the new 3G handsets than prior cell phones. Far from disappearing from cutting edge technology, the disdained passives are growing.
The best way to look at this is in a tear-down analysis of the latest 3G wireless handset. Portelligent Inc., Austin, Tex., regularly disassembles mobile and consumer electronic products -- from the shell casing all the way down to the passive components. President David Carey said he is constantly reminded that at the end of tearing down the most sophisticated product, you end up with a significant pile of mundane components.
Portelligent took apart a Matsushita Panasonic Foma 2101V 3G handset and found 600 passive components, 42 SAW devices and crystals and switches, only 30 ICs and 30 connectors. Carey said the latest model phone had twice the parts count of the garden variety handset.
The passives included 165 discrete resistors, 331 discrete capacitors, 11 ferrites, 11 inductors, 17 coils. Semiconductor discretes includes 29 transistors, 23 diodes and 13 white LEDs for the backlight of the TFT LCD display.
The Panasonic 3G phone used three processors -- a special purpose ASIC with embedded DSP, a baseband control DSP, and a Matsushita processor to run data applications. Memories included 2-megabytes of fast cycle RAM from Fujitsu, 35MB of flash from Mitsubishi and Sharp, and 9MB of SRAM from Samsung.
The handset included 4,000 solder joints connecting all the parts.
Yes, the Moore's Law rampup is exhilarating and mind-boggling. But as just one 3G cell phone proves: the undistinguished passives make it all work.