SAN JOSE, Calif. – An interview with a trio of senior Intel microprocessor designers provides a few details and raises more questions about the company’s latest move into analog design.
Intel designed an on-chip voltage regulator and external inductors to support it for Haswell, its next-generation x86. What’s not clear is to what extent the work is driving the digital giant into more design of analog components and processes.
Haswell has two power rails coming into its package compared to six for Ivy Bridge, its prior generation CPU. Inside the Haswell package, Intel splits up the two rails into as many as 12.
The Haswell package includes 20 or more Intel-designed inductors, one for each phase of each power rail. The inductors, like the on-die voltage regulator, are Intel made parts, replacing what used third-party analog parts on the motherboard outside the package.
“We save on board real estate, increase our headroom for turbo modes and get more fine grained control of power,” said Per Hammarlund, a chief SoC architect at Intel.
The move shaves $2-$10 off the motherboard bill of materials, depending on what version of Haswell OEMs are using. The chip will come in versions targeting tablets, notebooks, desktops and servers.
“There is a small net adder in power consumption [by putting the voltage regulator on die] but we’re also getting more power rails on the die controlled at finer granularity,” said Steve Gunther, lead power architect for Haswell.
The engineers said Intel designed and made the inductors used inside the Haswell package. However, they did not know if those inductors required an analog process technology that Intel supports.
“We are very adept at doing analog designs in all aspects, including I/O and PLLs” Hammarlund said. “We have some of highest speed, lowest power I/O available and this [voltage regulator design] builds on those capabilities,” he added.