ST introduces STM32G5 mixed-signal microcontrollers

STMicroelectronics has introduced the STM32G5 family of mixed-signal microcontrollers, combining higher processing performance with precision timing, analogue conversion, and programmable logic for industrial motor control and digital power applications.

The devices use an Arm Cortex-M33 processor operating at up to 280 MHz, delivering a stated benchmark score of 1,136 CoreMark. ST is positioning the family for power supplies used in data centres, photovoltaic inverters, electric vehicle charging equipment, industrial drives, robotics, and other systems requiring tightly controlled switching and measurement operations.

STM32G5 succeeds the STM32G4 mixed-signal family, which uses a Cortex-M4 processor operating at up to 170 MHz. The preceding generation achieved 569 CoreMark, giving the new architecture approximately twice the benchmark performance. Actual application throughput will depend on software execution, memory access, peripheral activity, and the control algorithms being implemented.

Digital power conversion requires continuous coordination between measurement and switching functions. A typical converter measures output voltage, current, and other operating conditions before using a control algorithm to adjust the switching sequence of its power transistors.

The interval between sampling a signal and applying the corresponding control action influences the response of the converter to changes in load or supply conditions. Delays can affect regulation and stability, particularly where switching frequencies are high and the permitted time for executing each control cycle is limited.

ST has incorporated a 12-channel high-resolution timer offering resolution down to 111 picoseconds. This allows switching events to be positioned more precisely than would be possible using a timer with a coarser time base, supporting applications where pulse-width modulation and the relative timing of power semiconductor switching events are important.

Timer resolution alone does not determine the accuracy of a power converter. Gate-drive propagation delays, transistor characteristics, measurement noise, dead-time requirements, and the physical layout of the power stage also influence the switching behaviour of the completed circuit.

Higher timing resolution can nevertheless give the control system finer adjustment of the switching signals. This is relevant to converters using silicon carbide or gallium nitride devices, where rapid switching transitions place additional demands on timing coordination and the management of electrical interference.

STM32G5 also integrates a 12-bit analogue-to-digital converter capable of sampling at up to five megasamples per second, compared with the four-megasample capability identified by ST for the preceding generation. The converter includes a pseudo-differential operating mode intended to improve measurement performance in suitable circuit configurations.

Analogue measurements establish the information available to the control algorithm. Higher sampling rates can allow more frequent observations of current and voltage, but measurement accuracy remains dependent on analogue signal conditioning, input noise, sampling configuration, and the behaviour of the connected sensors.

The microcontroller family includes fast comparators, with ST specifying propagation delays as low as 20 nanoseconds, alongside operational amplifiers and other analogue peripherals. Comparators can be used to identify electrical thresholds without waiting for the main processor to complete a software comparison, supporting rapid responses to selected operating conditions.

Additional hardware resources include a new motor position encoder, enabling position information to be handled through dedicated peripheral circuitry. Motor-control applications can require coordinated current, speed, and position measurements, and hardware assistance can reduce the amount of processor time needed to handle repetitive measurement and timing operations.

ST has also introduced a programmable logic array known as PLAy, containing 16 configurable logic elements. These can implement selected digital functions inside the microcontroller rather than requiring external logic components, potentially reducing board complexity where the supported functions match the application’s requirements.

The devices provide two Filter Mathematical Accelerators, or FMACs, compared with one in the STM32G4 family. These dedicated units support digital filtering operations, allowing relevant signal processing calculations to be handled without placing the complete computational burden on the main Cortex-M33 core.

Processor and memory resources have been expanded to support more demanding control software. The family provides up to 512 KB of embedded Flash, including an optional dual-bank arrangement, together with 96 KB of data Flash and SRAM featuring error-correction capabilities.

Dual-bank Flash can support firmware update strategies in which a new software image is written and checked without immediately overwriting the existing image. Its implementation must still account for boot configuration, application integrity, and recovery behaviour if an update is interrupted.

The Cortex-M33 architecture also brings Arm TrustZone security separation to the STM32G mixed-signal range. TrustZone allows suitable software designs to distinguish between secure and non-secure execution environments, helping protect selected code and data from unauthorised access.

ST identifies additional security capabilities, including support for post-quantum cryptographic requirements. The security of a deployed product will depend on how those hardware capabilities are implemented through firmware, provisioning, key management, and the maintenance of the device over its operating life.

Development support includes STM32CubeMX2 configuration tools, an updated hardware abstraction layer, and application-specific motor control and digital power software. Hardware evaluation options include the NUCLEO-G564RE board and Discovery kits for motor control and digital power applications.

Package options include exposed-pad variants intended to improve thermal dissipation in industrial designs. The thermal behaviour of a completed controller will still depend on PCB construction, ambient temperature, surrounding components, and the power dissipated during operation.

Single-core STM32G5 devices are in production, while the dual-core STM32G5D configurations are planned for 2027. Engineers evaluating migration from STM32G4 will need to compare processor behaviour, peripheral configuration, firmware requirements, and power-stage timing against the operating limits of their existing applications.