BMI325 | Bosch Sensortec | 6-axis MEMS IMU (3-axis accelerometer + 3-axis gyroscope, with built-in temperature sensor)

II. Core Performance Parameters

form

project

parameter

Accelerometer

±2g / ±4g / ±8g / ±16g, 16-bit ADC

gyroscope

±125 / ±250 / ±500 / ±1000 / ±2000 dps，16bit ADC

Output rate ODR

0.78125 Hz to 6.4 kHz, configurable via software

power supply

VDD Analog: 1.71‑3.63V;VDD‑IO: 1.08‑3.63V, with IO support for 1.8V logic levels, independently powered.

electric consumption

Full performance mode: 790μA;Normal mode: 690 μA;Standby: 15 μA

interface

I²C (Fm+), SPI, I³C high-speed interfaces (new-generation bus, multi-sensor networking)

FIFO

2KB on-chip cache, supporting storage of three-axis acceleration, gyroscope, temperature, and timestamps, reducing MCU wake-up frequency.

interrupt

INT1 and INT2: Two programmable interrupt output lines.

additional

Hardware timestamp < 40μs, hardware synchronization, rapid offset self-calibration, gyroscope sensitivity self-compensation.

III. On-Chip Hardware Intelligent Engine (Core Highlight)

Hardware event detection does not require extensive computation from the MCU, enabling continuous operation in a low-power domain, making it suitable for always-on standby monitoring.

A plug-and-play hardware pedometer, where step counting is completed internally by the chip, and the MCU directly reads the count value.

Single tap, double tap, triple tap: Tap and knock gestures recognition.

Posture and orientation detection, flat placement detection, active/resting wake-up/sleep mode.

Motion detection, free fall detection

The gyroscope performs rapid self-calibration, suppresses temperature drift, and reduces the overall calibration workload of the entire system.

Compared to BMI260, it features a newly added I3C interface, an upgraded FIFO capacity of 2KB, increased FIFO to 2KB, a built-in hardware step counter, and faster startup speed of 2.5ms; BMI325 is hardware-pin compatible with BMI323, and its calibration algorithm further optimizes Bosch Medi......。

IV. Typical Application Scenarios

TWS True Wireless Earbuds: Wear Detection, Tap Gestures, Posture Control, Step Counting

Wearable devices: fitness bands, smart watches, motion tracking, step counting.

Smartphones and tablets: posture, image stabilization, screen rotation

IoT remote controls, VR/AR accessories, pen-like gesture sensors

Battery-powered wireless sensors, portable medical devices for motion capture.

Positioning: A new generation of consumer-grade six-axis IMU, featuring compact size, low power consumption, I3C high-speed bus, and built-in hardware step counter, targeting battery-powered consumer devices.

V. PCB Layout Design Considerations

LGA-14 bottom pads; the PCB package strictly follows the official Bosch library, with relatively high difficulty for manual soldering; prioritize SMT mass production.

Place 0.1μF ceramic decoupling capacitors as close as possible to the VDD and VDD-IO pins, minimize trace length, and reduce noise;

Keep I3C/I2C/SPI signal lines as short as possible, away from noise sources such as power supplies and inductors to avoid orientation drift;

Interrupt pins INT1/INT2 can be configured as push-pull/open-drain, with IO domain levels following VDD‑IO; note the need for pull-up voltage matching.

The PCB area beneath the chip should remain as a complete plane as possible, avoiding any cuts or segmentation, as MEMS sensors are highly sensitive to ground noise;

The device should be kept away from vibration sources and high-power heat-generating components, as temperature fluctuations can directly affect the gyroscope's zero drift.

For technical and selection requirements, please contact: 182778968089.