Where do I start when choosing an STM32?

Start with the application, not the part: list the control loops, communication interfaces, sensor count and power budget, then estimate the compute and memory the firmware needs. Those numbers narrow the family quickly. Then confirm the peripherals and package the board requires.

When do I need a Cortex-M7 instead of a Cortex-M4?

Choose a Cortex-M7 when the design needs much more compute or memory, such as advanced control, audio or graphics, or edge processing. The Cortex-M4 covers most mainstream control and motor work. The two share the STM32Cube ecosystem, so the software moves with modest change.

Does the toolchain change between families?

No. STM32CubeIDE and the STM32Cube software ecosystem cover the whole family, with HAL and LL drivers, middleware and configuration tools. That shared ecosystem is the main reason to standardize on STM32.

Why does the ADC not reach its rated accuracy?

The most common causes are a noisy or poorly decoupled analog supply, a weak analog ground, and an analog reference that is not stable. Decouple the supply close to the pins and use a clean reference. Separate the analog ground return from the digital switching currents.

How should I decouple the STM32 supplies?

Place the decoupling capacitors as close to the supply pins as the layout allows, use the values the datasheet recommends for each rail, and provide a solid ground plane beneath the device. Long traces from the capacitor to the pin defeat the purpose.

Why do low-power modes not reach the datasheet current?

Unused pins left floating, external components powered from the MCU rails, or a regulator with high quiescent current can all raise the measured current above the datasheet figure. Terminate unused pins and check the regulator's own current draw.

My IGBT bridge runs hot. Where do I start?

Start by separating conduction loss from switching loss: measure the device temperature at low and high switching frequency. If the temperature rises steeply with frequency, the loss is switching-related. Then examine the gate drive and the diode recovery.

Why is my gate waveform ringing?

Gate ringing is parasitic oscillation between the gate capacitance and the inductance of the gate loop. Shorten the gate loop, increase the gate resistance in small steps, and add a ferrite bead close to the gate if needed. Layout dominates the result.

How does diode recovery affect loss?

During freewheeling, the antiparallel diode conducts and then recovers, and its recovery current adds to the switching loss and EMI. A soft-recovery diode, such as the one paired with the HB-series IGBT, reduces both. Confirm the diode against your switching frequency.

How do I choose the accelerometer full-scale range?

Choose the smallest range that covers the motion you expect, because a smaller range gives finer resolution. Use a wider range only for high-g events such as shock or free-fall detection. Match the range to the application, not to the maximum the part offers.

How accurate is the pressure sensor for altitude?

The LPS22HB provides 24-bit pressure output with fine resolution, which gives good altitude resolution when combined with the embedded temperature compensation. Follow the recommended one-point calibration after soldering for best accuracy.

How do the sensors save power?

Both draw very little current and include low-power modes; the accelerometer adds embedded event detection and FIFO, so the host can sleep and wake only on an event. Configure the output data rate to match the application.

How do I calculate the junction temperature?

Multiply the power dissipation by the total thermal resistance from junction to ambient, including the package, the interface and the heatsink, then add the ambient temperature. Keep the junction below the rated maximum with margin.

Why does the switching loop layout matter?

The loop carrying the switched current radiates EMI and adds parasitic inductance that raises voltage overshoot. Keep it as small as possible and return the current directly beneath the trace. Layout is as important as the component choice.

How do I protect against inductive loads?

Use devices with avalanche and dv/dt ratings, keep the loop tight, and add clamping or snubbing where the load is highly inductive, such as a motor or relay. Confirm the worst-case spike against the device rating.

Technical Support | STMicroelectronics Expertise | BeiLuo

Guides, application notes, troubleshooting and reviews from BeiLuo's FAE team, covering STM32 microcontrollers, STPOWER MOSFETs and IGBTs and MEMS sensors.

Guides 2 Application Notes 1 Troubleshooting 1 Reviews 1

How to Select an STM32 Family for Your Embedded Design

2026-09-20 - Guides - By Wei

Compare STM32 Cortex-M0, M4, M7 and M33 families by core, memory, peripherals, power and security to choose the right microcontroller for your embedded design.

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MOSFET Thermal and Layout Guide for Motor Drives

2026-08-23 - Guides - By Hao

How to plan the thermal path and power layout for STPOWER MOSFETs in motor drives so the bridge runs cool, switches cleanly and survives inductive loads.

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STM32 Power Supply and Decoupling Application Note

2026-09-13 - Application Notes - By Wei

Practical guidance for designing the power supply, decoupling and analog reference of an STM32 design so the ADC, clocks and low-power modes meet their specification.

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Troubleshooting IGBT Gate Drive and Switching Losses

2026-09-06 - Troubleshooting - By Hao

A systematic procedure for diagnosing excess switching loss, gate ringing and diode recovery problems in STPOWER IGBT bridge designs, with the checks that find the cause fastest.

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ST MEMS Sensors: LIS3DH and LPS22HB Review

2026-08-30 - Reviews - By Lei

A practical review of the ST LIS3DH accelerometer and LPS22HB pressure sensor for low-power sensing, covering accuracy, power modes, interfaces and integration.

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Meet Our FAE Team

Wei

FAE Engineer, STM32 and Embedded Systems

STM32Embedded DesignPower DesignLow Power

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Hao

FAE Engineer, Power Semiconductors

IGBTsMOSFETsGate DriveThermal Design

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Lei

FAE Engineer, MEMS and Sensing

MEMS SensorsEnvironmental SensorsLow PowerIntegration

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