NXP Semiconductors MMA3221KEG

Overview

MMA3221KEG from Freescale Semiconductor is a dual-axis (X/Y) surface-micromachined capacitive accelerometer with integrated signal conditioning, factory-calibrated ±50g X-axis and ±20g Y-axis full-scale range, 4th-order Bessel low-pass filter (360–440 Hz), and self-test functionality. It operates over –40°C to +105°C, consumes 6–10 mA at 4.75–5.25 V, and is qualified to AEC-Q100 Grade 2 for automotive and industrial vibration monitoring.

For engineers reviewing the MMA3221KEG datasheet, MMA3221KEG pinout, MMA3221KEG application, or MMA3221KEG equivalent, this page delivers verified technical context, SOIC-20 pin mapping, calibrated sensitivity values, self-test timing (9–14.4 g response), status fault latching behavior, and real-world use cases in hard drive protection, impact sensing, and VR input devices.

Technical Context

The MMA3221KEG integrates a hermetically sealed polysilicon g-cell transducer with a CMOS ASIC using switched-capacitor measurement, ratiometric analog output, and on-chip 70 kHz oscillator-driven filtering. Its dual independent outputs (XOUT, YOUT) provide linear voltage responses referenced to VDD/2, with zero-g offsets trimmed to 0.41–0.56 × VDD and sensitivities of 38–42 mV/g (X) and 95–105 mV/g (Y).

Self-test activation applies electrostatic force via a dedicated ST pin, deflecting the center plate to produce calibrated output shifts; the STATUS pin latches high on EPROM parity error, low-voltage detect (2.7–4.0 V trip), or clock monitor failure (50–260 kHz range), and resets only upon ST pulse if fault persists.

Key Specifications

Pinout & Package

Package: 20-lead SOIC (Case 475A-02), surface-mount, Pb-free (KEG suffix). Dimensions per Freescale Issue C drawing: 0.380" × 0.250", 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-axis analog accelerometer applications.

Compared with ADXL202E and MMA8452Q, the MMA3221KEG uniquely delivers factory-calibrated dual-axis analog outputs with asymmetric full-scale ranges, integrated Bessel filtering, and hardware-latched fault signaling-making it irreplaceable in legacy analog designs requiring guaranteed ±50g shock tolerance and AEC-Q100-compliant reliability.

Availability

MMA3221KEG is available at Aetrix Electronics and suitable for vibration monitoring, hard drive protection, and appliance control requiring stable component supply across automotive, industrial, and consumer electronics production programs.

Supply support for MMA3221KEG includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, sensors, and analog solutions for automotive, industrial, and IoT markets.

The MMA3221KEG belongs to Freescale's Xtrinsic™ family of intelligent sensors, designed specifically for robust, high-reliability motion sensing in safety-critical and thermally demanding applications.

FAQ

What is the full-scale acceleration range of the MMA3221KEG on each axis?

The MMA3221KEG has an asymmetric dual-axis full-scale range: ±50 g on the X-axis and ±20 g on the Y-axis. This is factory-set and does not require external components. The specification is confirmed in Table 2 of the official Freescale datasheet Rev 1 (11/2012), where gFS min/max values are listed as 112.5/–112.5 g (X) and 33.75/–33.75 g (Y), corresponding to ±50 g and ±20 g respectively at typical conditions.

Does the MMA3221KEG provide analog or digital output signals?

The MMA3221KEG provides ratiometric analog voltage outputs on two dedicated pins: XOUT (pin 6) and YOUT (pin 11). Each output is centered at approximately VDD/2 at 0 g and scales linearly with acceleration (e.g., 38–42 mV/g for X, 95–105 mV/g for Y). It does not include I²C, SPI, or PWM interfaces - all signal conditioning and filtering are analog, making MMA3221KEG distinct from later digital-output accelerometers like the MMA8452Q.

How does the self-test function work on the MMA3221KEG?

The MMA3221KEG self-test is activated by applying a logic-high signal to the ST pin (pin 5) for ≥100 µs. This triggers an electrostatic force that deflects the internal g-cell's movable plate, producing a calibrated output shift equivalent to 9.6–14.4 g on both XOUT and YOUT. The STATUS pin reflects self-test activity in real time and latches faults independently. This behavior is fully documented in the "SPECIAL FEATURES" section and Table 2 of the MMA3221KEG datasheet.

What is the purpose of the separate AVDD and VDD pins on the MMA3221KEG?

The MMA3221KEG uses AVDD (pin 10) for analog circuitry biasing and VDD (pin 9) for digital logic and oscillator supply. This separation minimizes noise coupling from digital switching into the sensitive analog signal path. Both rails accept 4.75–5.25 V, but must be decoupled independently: a 0.1 µF capacitor is recommended on VDD, and AVDD requires clean, low-noise routing - a design requirement explicitly stated in the "BASIC CONNECTIONS" section of the datasheet.

Is the MMA3221KEG RoHS compliant and what does the 'KEG' suffix indicate?

Yes, the MMA3221KEG is RoHS compliant. The 'KEG' suffix explicitly denotes Pb-free (lead-free) packaging, as confirmed in the "MMA3221KEG" header block and ordering information table of the datasheet. It is supplied in a 20-lead SOIC package (Case 475A-02) and qualifies under AEC-Q100 Grade 2, ensuring compliance with automotive environmental and reliability standards including lead-free reflow profiles.