CEO interview: Ambiq sees broader options for low voltage

August 25, 2015 // By Peter Clarke
Mike Noonen, recently appointed interim CEO at microcontroller startup Ambiq Micro, discusses the focus and opportunities for this pioneering company designing circuits that can operate below the threshold voltage of the constituent transistors.

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.

EE Times 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.

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