NXP Semiconductors MMA7361LR2

Overview

MMA7361LR2 from Freescale Semiconductor is a 3-axis capacitive MEMS accelerometer with integrated signal conditioning, selectable ±1.5g/±6g ranges, 0g-detect for freefall protection, and sleep mode consuming only 3 μA. It delivers ratiometric analog outputs (XOUT/YOUT/ZOUT), operates from 2.2–3.6 V, and is used in HDD drop protection, laptop anti-theft, and motion-based cell phone interfaces.

For engineers reviewing the MMA7361LR2 datasheet, MMA7361LR2 pinout, MMA7361LR2 application, or MMA7361LR2 equivalent, key selection criteria include its LGA-14 package footprint, g-select logic-controlled sensitivity switching, self-test verification capability, and 0g-detect interrupt signaling for system-level freefall response.

Technical Context

The MMA7361LR2 integrates a surface-micromachined polysilicon g-cell sensor with an ASIC featuring switched-capacitor readout, on-chip 1-pole low-pass filtering, temperature-compensated offset and sensitivity, and digital control logic for Sleep, g-Select, and Self Test functions. Its output is ratiometric to VDD, enabling direct interfacing with microcontroller ADCs without external reference voltage.

It uses internal NVM trimming for factory-calibrated zero-g offset and sensitivity across all three axes, eliminating need for external calibration components. The 0g-Detect output asserts high when |X|, |Y|, and |Z| acceleration are all within ±0.4 g - a hardware-level freefall trigger independent of host processing.

Key Specifications

Pinout & Package

Package: 14-pin LGA (3 mm × 5 mm × 1.0 mm, Case 1977-01), RoHS-compliant, surface-mountable with solder-mask-defined footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-axis analog-output accelerometer applications.

Compared with ADXL335 and MMA8451Q, the MMA7361LR2 uniquely combines analog outputs, hardware 0g-Detect, and sub-10 μA sleep power in a single LGA-14 package - making it optimal for cost-sensitive, battery-powered systems needing deterministic freefall response without host processor overhead.

Availability

MMA7361LR2 is available at Aetrix Electronics and suitable for laptop anti-theft systems, portable media player drop protection, and motion-enabled mobile handsets requiring stable component supply across extended production lifecycles.

Supply support for MMA7361LR2 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) was a pioneer in MEMS sensor integration, delivering high-volume, automotive-qualified inertial sensors with embedded signal conditioning.

The MMA7361L family was designed specifically for consumer electronics requiring low-cost, low-power, and highly integrated motion sensing - targeting handheld, portable, and battery-operated applications where size, power, and reliability are critical.

FAQ

What is the function of the g-Select pin on the MMA7361LR2?

The g-Select pin (Pin 10) configures the MMA7361LR2's full-scale range: logic low selects ±1.5g (800 mV/g sensitivity), and logic high selects ±6g (206 mV/g). An internal pull-down resistor ensures ±1.5g operation if the pin is left unconnected. This allows dynamic range adjustment without external components or firmware recalibration - a key feature of the MMA7361LR2 for multi-mode motion sensing.

How does the 0g-Detect feature work in the MMA7361LR2?

The 0g-Detect output (Pin 9) goes high when acceleration magnitude on all three axes falls within ±0.4 g - indicating near-weightlessness consistent with freefall. It is a hardware-comparator-based signal, independent of host software, with propagation delay under 2 ms. This makes the MMA7361LR2 ideal for time-critical applications like HDD head parking, where the MMA7361LR2's 0g-Detect output can trigger immediate action without MCU intervention.

What is the recommended external capacitance for the MMA7361LR2 analog outputs?

A 3.3 nF capacitor is recommended on each of XOUT, YOUT, and ZOUT to suppress clock noise from the internal switched-capacitor filter. This value sets a 1.5 kHz cutoff frequency (f = 1/(2π × 32 kΩ × 3.3 nF)), which exceeds the device's 400 Hz XY bandwidth while attenuating the 11 kHz internal sampling clock. Using this capacitor ensures clean analog signals for the MMA7361LR2's outputs and prevents aliasing in downstream ADC sampling.

Can the MMA7361LR2 operate from a 1.8 V supply?

No - the MMA7361LR2 requires a minimum supply voltage of 2.2 V and maximum of 3.6 V, as specified in its Absolute Maximum Ratings and Operating Characteristics tables. Operation below 2.2 V may result in undefined behavior, degraded sensitivity, or failure to meet datasheet specifications. For 1.8 V systems, alternative accelerometers such as the MMA8451Q or LIS3DH should be considered instead of the MMA7361LR2.

What is the purpose of the Self Test pin on the MMA7361LR2?

The Self Test pin (Pin 13) initiates an electrostatic actuation sequence that deflects the MEMS sensing element, simulating ~1g acceleration on the Z-axis and smaller deflections on X/Y. This verifies both mechanical integrity (g-cell movement) and electrical signal chain (analog output response) before or after PCB assembly. Engineers use the MMA7361LR2's Self Test to validate solder joints and confirm functional readiness - a critical step in high-reliability consumer device manufacturing.