BMI325 Bosch | Consumer-grade 6DoF IMU (3-axis accelerometer + 3-axis gyroscope + on-chip temperature sensor)

✅I. Core Electrical Parameters

Package: LGA-14, 2.5 × 3.0 × 0.83 mm

Supply voltage: 1.71V ~ 3.63V, directly compatible with lithium batteries and 3.3V MCUs.

ADC Resolution: Both accelerometer and gyroscope are 16-bit.

Acceleration measurement range (configurable via software): ±2g / ±4g / ±8g / ±16g

Gyroscopic range (software-configurable): ±125 / ±250 / ±500 / ±1000 / ±2000 dps (°/s)

ODR (Output Data Rate): 0.78125 Hz to 6.4 kHz, with programmable low-pass filter.

Communication Interface [Core Selling Point]: I3C (12.5MHz) + I2C (1MHz) + SPI (10MHz, 3/4-line)

FIFO cache: 2KB, supports timestamp synchronization.

Temperature range: -40°C to +85°C (consumer-grade, not automotive-grade)

electric consumption

Accelerate + Gyro Full Open High-Performance Mode: Typical 790μA

Standby current: 15μA

It supports multiple levels of sleep mode and event-based wake-up, sampling at high rates only during physical activity to conserve power.

✅II. Built-in Hardware Function Engine (Reducing MCU Computational Load)

Step Counter

Single/Double Tap Click Detection

Tilt detection, motion wake-up, static detection

Gyroscope CRT continuous self-calibration, suppressing temperature drift.

Built-in self-test, over-range detection, interrupt output pin.

Advantages: Many events can trigger interrupts directly through chip hardware, eliminating the need for the MCU to continuously poll and read data.

✅III. Horizontal Comparison Within the Same Series (Most Commonly Used by Customers for Replacement)

form

model

Location

Key differences

BMI325

New Generation General-Purpose Consumer 6-Axis

Newly added I3C, pin-compatible with BMI323/BMI160, power optimization, 6.4kHz high ODR (Overdrive Rate)

BMI323

Basic model, universal 6-axis

No I3C, I2C/SPI, cost-effective entry-level model

BMI260/BMI270

Flagship Wearables

Lower noise, specialized watches and wristbands, higher price.

BMI330

Industrial style

Temperature range - 40~105°C, industrial scenarios, not suitable for headphone wear.

Key points: The BMI325 (PIN-to-PIN compatible with BMI323 and BMI160) allows direct upgrades for existing projects without requiring PCB revisions, and with I3C adaptation, it supports new-generation main controllers.

✅IV. Typical Application Scenarios (Recommendation List for Clients)

Smart TWS Earbuds: Tap Gesture, Wear Detection, Posture Recognition

Smart bands and watches: step counting, activity recognition, flip-screen activation, and screen-on-rotation features.

Game controllers and remote controls: motion sensing, joystick assistance.

Portable IoT, pen, smart remote control, gimbal, small vacuum cleaner status

Mobile phone posture assistance, foldable notebook opening/closing detection.

✅V. Selection Advantages (Sales Script)

Triple-interface integration: I3C is currently the preferred bus for high-end wearable platforms, offering faster speeds, fewer pins, and better power efficiency compared to I2C. It should be prioritized in new projects.

High ODR of 6.4kHz, with low latency for gesture and motion tracking.

It comes with a built-in motion event engine, reducing the load on the MCU and shortening the development cycle.

Bosch MEMS gyroscope self-calibration, with stable temperature drift control.

Small LGA package, suitable for wearable products with limited PCB space, ideal for wearables with tight PCB space constraints.