The **AD22284-A-R2** is a specialized high-performance dual-axis accelerometer designed primarily for automotive safety applications, such as airbag deployment and impact sensing. It is manufactured by Analog Devices and belongs to their surface-micromachined iMEMS (integrated Micro-Electro-Mechanical Systems) series. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Sensing Axes** | Dual Axis (X and Y) | | **Measurement Range** | ±35 g / ±35 g | | **Output Type** | Analog (Voltage proportional to acceleration) | | **Sensitivity** | 55 mV/g (typical) | | **Operating Voltage** | 4.75V to 5.25V | | **Supply Current** | 6 mA (max) | | **Package Type** | 8-Lead CLCC (Ceramic Leadless Chip Carrier) | | **Operating Temperature** | -40°C to +105°C | --- ### 2. Functional Core Components The device integrates several critical electronic sections onto a single monolithic chip: #### A. Sensor Structure (MEMS) The chip contains a polysilicon surface-micromachined structure (the "proof mass") suspended over a silicon wafer by springs. When acceleration occurs, the mass deflects, changing the capacitance between the fixed plates and plates attached to the moving mass. #### B. Signal Conditioning - **Demodulator:** Converts the capacitive changes into a voltage signal. - **Amplifier:** Boosts the signal to a usable level (mV/g). - **Low-pass Filter:** Pre-configured to suppress high-frequency noise and mechanical resonance, ensuring signal integrity for safety-critical decisions. #### C. Self-Test Circuitry The device includes a digital self-test pin. When activated, an electrostatic force is applied to the sensor beam to simulate a mechanical load, allowing the system to verify that both the mechanical and electronic parts are functioning correctly. --- ### 3. Pin Configuration (Typical) | Pin No. | Name | Function | | :--- | :--- | :--- | | 1 | ST | Self-Test Input | | 2 | YOUT | Analog output for Y-axis | | 3 | XOUT | Analog output for X-axis | | 4 | VSS | Ground | | 5 | NC | No Connection | | 6 | NC | No Connection | | 7 | VDD | Positive Supply Voltage (5V) | | 8 | NC | No Connection | --- ### 4. Application Context The "R2" suffix typically denotes the packaging format (Reel size). Because of its high reliability and specific G-range (±35g), this part is almost exclusively used in: * **SRS (Supplemental Restraint Systems):** Airbag control units. * **Vehicle Dynamics:** High-impact detection. * **Industrial Vibration:** Monitoring heavy machinery where high-G events occur.