Last week, while watching a video of my friend Dave Jones tear down an old Fluke 91 ScopeMeter DSO (digital sampling oscilloscope), I suddenly realized that this 20-year-old piece of test gear brought the decade-long decline of ASIC (Application-Specific Integrated Circuit) design starts into sharp relief.
Dave cracked open his eBay ScopeMeter and revealed the instrument's two main circuit boards: one digital and one analog. The ScopeMeter's digital board contains two ASICs plus an 83C196 mask-programmed, 16-bit microcontroller from Intel's old MCS-96 family. The SoC (System-on-Chip) era started in 1995 and Fluke built this DSO in 1994, just before processors started to climb aboard ASICs, which is why there's a separate on-board microcontroller.
The digital ASICs on the ScopeMeter's digital board appear to be a Flash-memory/keyboard controller (labeled "Fluke MASIC," fabricated by Hitachi) and a timebase/trigger/event-counter/display processor (labeled "Fluke D-ASIC," fabricated by LSI Corp.). There's a third ASIC fabricated by Philips -- an analog chip on the DSO's analog board -- that incorporates amplifiers, analog switches, and track-and-hold circuits for two analog signal channels. That's two digital ASICs and one analog ASIC designed into a relatively small instrument that sold for $1,000 or $2,000 nearly 20 years ago.
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