Ambiq subthreshold transistor technology enables power consumption levels as low as 6μA/MHz

As a supplier of ultra-low power processor solutions for Internet of Things (IoT) applications, Ambiq's unique Subthreshold Power Optimization Technology (SPOT) platform can greatly optimize the power consumption of products.

Subthreshold transistor technology

A transistor is "on" when it reaches or exceeds its threshold voltage. Conventional transistor circuits are designed for superthreshold operation; however, this results in high power consumption.

Compared to conventional superthreshold transistor circuits that operate at 1.8 V, transistor circuits using the subthreshold region can operate at 0.3 V.

This lower voltage not only saves the cost of design complexity, but also reduces static and dynamic power consumption.

Apollo3 Blue Plus development board based on the subthreshold power optimization technology platform. Image provided by Ambiq

Designing systems consisting of transistor circuits operating at subthreshold voltages presents some daunting challenges.

These challenges may include:

Logical fluctuations

noise

Current change

temperature change

Most of the time, logic swing and noise affect the operation of the circuit.

As the voltage changes, the current changes exponentially, but these current changes are so small that they are difficult to detect.

Additionally, temperature variations may affect the operation of subthreshold circuits because temperature affects the threshold voltage (Vth) of transistors.

When a subthreshold circuit is operated at high temperature, the off-state current value may be similar to the on-state current value of the uncompensated circuit at low temperature.

For years, Ambiq’s designers have been working to address the challenges associated with subthreshold technology.

Fumihide Esaka, chairman and CEO of Ambiq, said the company has been providing record-breaking low-power technology platforms and processor solutions for the Internet of Things.

The company's subthreshold circuit solution SPOT can provide high-efficiency, ultra-low power consumption and more cost-effective MCU and system-on-chip (SoC) devices.

Ambiq's Subthreshold Power Optimization Technology Solution

The proprietary SPOT platform claims to provide the most energy-efficient solution for wearables, IoT, battery-powered and other wirelessly connected applications.

The Apollo series microprocessors based on the SPOT platform have powerful functions and can meet the requirements of designers in data storage, sensing, security, communication and other aspects. 

Block diagram of the Apollo2 Thin microprocessor, which features a power management unit that provides optimized active and sleep mode power to the device. Image courtesy of Ambiq

The microcontrollers have clock speeds ranging from 24 MHz to 96 MHz and run a 32-bit Arm Cortex-M4F in their processing core.

With MCU power efficiency as low as 6 μA/MHz, these microprocessors are expected to meet the most battery-constrained processing needs.

One of the products based on the SPOT platform, Apollo2 Thin, can operate in the voltage range of 1.755 V to 3.63 V.

With its subthreshold power optimization technology platform, Ambiq hopes to launch energy-saving products and powerful solutions with higher performance in battery-powered IoT end devices.