In January 2015 Ambiq Micro Inc. (Austin, Texas) introduced the Apollo family of Cortex-M4F-based microcontrollers. These MCUs can operate at voltages below 0.5V and the company claims that this can provide a 10-fold improvement in MCU power consumption compared with competitors’ MCUs. This is mainly based on the fact that power consumption scales with the square of voltage, although the achievable clock frequency for digital circuits also reduces with the voltage.
However, Ambiq’s sub-threshold technology is not limited to MCUs. MCUs are almost always mixed-signal circuits and Ambiq already sells a range of real-time clock (RTC) circuits based on its technology. Noonen’s ambitions for the company are broad.
Noonen is a widely experienced semiconductor executive and also serves on the board of directors of Kilopass Technology Inc. (San Jose, Calif.) a pioneer of NVM antifuse technology, is chairman and co-founder of Silicon Catalyst, a semiconductor-oriented startup incubator based in Silicon Valley and also sits on the boards of directors of Adapteva and a stealthy startup called Quora Semiconductor.
eeNews Europe started by asking if the move by leading foundry Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC) to introduce ultra-low power versions of its manufacturing processes at 55, 40, 28 and 16nm nodes was a welcome development and something that Ambiq could use.
TSMC is offering ULP processes that operate below 1V at 55, 40 and 28nm while the 16FFC FinFET process operates at voltages down to 0.55V. These processes have all been described as offering near-threshold voltage operation. As a fabless pioneer of sub-threshold circuit operation spun out of the University of Michigan in 2010, Ambiq has had to perform its own process characterization for its low voltage use of foundry processes.
“What TSMC has done is moving things in the right direction although, near-threshold is quite a way above the [voltage] world where Ambiq lives. But it is a good thing for Ambiq. The platforms make our lower voltage development work easier,” said Noonen.
Emphasizing the advantage that Ambiq’s SPOT (Sub-threshold Power Optimized Technology) brings Noonen added that the Apollo series is currently based on 90nm CMOS process from TSMC. “What we have at 90nm is better than what other companies have at 55nm,” he states.
Noonen said he is not ready to disclose the next manufacturing node Ambiq will use but said that the Ambiq technology is applicable to multiple process technologies including fully-depleted silicon-on-insulator (FDSOI) processes. Back in 2013, when Noonen was executive vice president of marketing and sales at Globalfoundries Inc. he was an advocate of that company’s adoption of FDSOI.
For now FDSOI processes are only being offered at 28nm by STMicroelectronics and Samsung and at 22nm by Globalfoundries and without a declared non-volatile memory option. This is not beyond Ambiq’s requirements if it starts targeting SoCs.
Mike Noonen, interim CEO at Ambiq Micro Inc.
And despite the technical claims for SPOT and the Apollo microcontroller range, MCU buying decisions are often based on the maturity of development environments and relationships with major vendors. Some of the leaders in microcontroller sales include: NXP, Freescale, Texas Instruments, STMicroelectronics, Microchip and Atmel. Has this been a problem for Ambiq?
Noonen responded: “Our first major customer will launch in the fourth quarter. As to competition, what you say may be true in the traditional embedded space where there can be long development cycles. So the best way forward is to target a market that doesn’t have so many legacy issues. Wearables is that market for us because it’s a new market and hypersensitive to battery life.”
Next: Not limited to the MCU
With regard to the third-party ecosystem to support the ARM-based Apollo microcontrollers Noonen said that the ARM Keil tool chain and IAR Systems provide support as well as internal GCC compiler and debuggers.
In many wearable systems the MCU is only part of the solution, being deployed alongside sensors, sensor hubs, power management ICs and wireless transceivers. As such saving power in the MCU is only a portion of the overall requirement and some equipment is based on highly integrated system-on-chip (SoC) designs. Does Ambiq intend to move into any of these other areas?
“Our capability for power saving is not limited to the MCU,” said Noonen. At present one of the things that Ambiq provides to developers is head-room to run more sophisticated sensor algorithms which produce superior results to the competition at reduce power consumption he added. “We can provide help to sensor and connectivity partners and we do have a holistic energy focus,” said Noonen referencing work being undertaken with Dialog Semiconductor on reference boards.
It may sound like Noonen is trying not to appear threatening to current semiconductor partners but nonetheless, the opportunity remains for Ambiq to start adding wireless and other circuits to its product offerings using SPOT. ARM is now offering a Bluetooth connectivity package of IP under the name Cordio. Noonen declined to say whether Ambiq has licensed the Cordio technology from ARM.
Another area of relevance to all low power systems is embedded non-volatile memory, often seen as a key to fast shut-down and wake up operations to allow power saving. However, while embedded flash memory has been deployed at CMOS logic nodes, due to problems with scaling, rival technologies may displace it for embedded memory at 28nm and below.
Is this something that Ambiq ponders or do they just work with whatever embedded memory a chosen foundry can provide?
“There is a renewed opportunity in memory in general. And for the Internet of Things having non-volatile memory is vital. There’s flash, one-time-programmable antifuse and many other choices,” said Noonen reminding us that he is also on the board of Kilopass Technology Inc. (San Jose, Calif.) a licensor of NVM antifuse technology. “Having a broader understanding of memory certainly helps,” he adds Noonen.
Next: Ambiq and PsiKick
We also asked Noonen about the chances of Ambiq working with, or acquiring another company that has specialized in sub-threshold voltage operation, PsiKick Inc. (Charlottesville, Virginia).
That company launched a couple of years after Ambiq and has focused on developing wireless sensor network SoCs. With operations down to 0.25V it claims it can provide a 100 to 1,000-fold improvement in power consumption in a single chip compared with multi-component solutions.
Noonen points out affinities between Ambiq and PsiKick without indicating any closer ties. “PsiKick came out of the University of Michigan, like Ambiq did. We think the fundamental philosophy of sub-threshold can be applied in multiple directions. Previously this sort of technology was only used for hearing aids and Swatch watches. There’s plenty of room for multiple companies to work in energy optimization,”
In December 2014, Ambiq raised a $15 million round of venture capital led by Kleiner Perkins Caufield & Byers and has no immediate need of additional capital, Noonen said. “Now the job is to get lots of design wins.” Ambiq has already sold out its first batch of evaluation kits having shipped several hundred but expects to have them available again within a matter of days.
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