The glory of Apple chips began with this company

Source: Content compiled by Semiconductor Industry Observer (ID: icbank) from cpushack , thank you.

When Apple acquired PA Semi in 2008, it was the beginning of the iPhone era, and there was a lot of speculation as to why Apple would acquire a company that made low-power, high-performance PowerPC processors. Especially since the iPhone runs on ARM and the Mac had already migrated from PowerPC to x86.

PA Semi was founded in 2003 by Daniel Dobberpuhl (who passed away in 2019). Dobberpuhl was one of the true greats of microprocessor design, starting his career at DEC with the T-11 and MicroVAX, then helping DEC transition to Alpha RISC design (21064). It was Dobberpuhl who created the design center at Pal Alto (where PA Semi later got its name) that designed DEC's StrongARM processors. A processor that was later purchased by Intel and became the XScale line of ARM processors.

After Intel acquired the StrongARM product line, he helped start SiByte to make MIPS-based RISC CPUs, and continued to do so after SiByte was acquired by Broadcom. So when he started PA Semi, it was more about RISC than PowerPC, which just happened to be the architecture they chose to use. The design team had extensive experience with various CPU architectures, including SPARC, Itanium, and early Opterons. From this you can see why this acquisition was so attractive to Apple.

In the years between PA's founding and Apple's takeover (2003-2008), they did design, market, and sell a line of PowerPC processors based on what they called the PA6T core, called PWRficient. The PA6T-1682M is a dual-core PowerPC processor (the 13xxM is a single-core version) that runs up to 2GHz per core, has 64K of L1 instruction cache, and 64K of L1 data cache. They are manufactured by TI using a 65nm process and run at 1.1V. The L2 cache is scalable and shared between the cores. In the 1682M, this is a 2M 8-way cache with ECC. One of the most useful features is their clock stepping. They can drop down to 500MHz at only a few watts per core, and then recover to the full 2GHz in 25us.

The PA6T was only on the market for a few months (from late 2007 to April 2008) before Apple bought it for $300 million, but during that time PA Semi scored numerous design wins. Amiga chose it for the AmigaOne X1000 computer. The AmigaOne didn't ship until 2011, which means that while PA Semi was acquired and fully controlled by Apple, they continued to manufacture, support, and supply 1682M CPUs to their former customers. Surely the Amiga wasn't enough to push Apple to continue making chips?

They weren't, but others were, and the PA6T was such a great processor that it was chosen and designed into many computer systems by US defense contractors, and if anyone doesn't like change, its defense contractors, so there is some push from the US Department of Defense, Apple went ahead and produced (or rather had TI produce) the PA6T processor. Curtis-Wright designed the PA6T into their new CHAMP-AV5 DSP VME64 board, which is used for signal processing in numerous military applications. They also used the PA6T (1.5GHz) in their VPX3-125 SBC. Themis computers, NEC, Mercury, and others designed in the PA6T. Another manufacturer of boards based on the PA6T, Extreme Engineering, called the design "groundbreaking."

It would have been interesting to see what PA Semi would have accomplished if it hadn't been swallowed up by Apple. Obviously, we saw what the PA team accomplished at Apple with its A-series processors, but it's clear that PA also had something special to say about the PowerPC architecture.

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