MMA6813BKCWR2 - Dual-Axis 50g SPI Accelerometer | NXP
MPN: MMA6813BKCWR2 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.36 | $5.36 |
| 10 | $5.09 | $50.90 |
| 100 | $4.55 | $455.00 |
| 500 | $4.1 | $2,050.00 |
| 1,000 | $3.75 | $3,750.00 |
MMA6813BKCWR2 Overview
An accelerometer (also called a g-sensor or gravity sensor) is a micro-electromechanical (MEMS) device that converts mechanical acceleration into an analog or digital output. In the system taxonomy, an accelerometer belongs to motion sensors -> inertial sensors -> sensors. The MMA6813BKCWR2 falls under medium-g (>10g) lateral accelerometers, which are over-damped to suppress high-frequency vibration and provide clean signals during crash or chassis events.
Key features include a 10-bit digital SPI output, self-test capability, low current consumption suitable for always-on automotive sensing, internal signal conditioning, and a SafeAssure safety designation. The QFN-16 6x6 mm package with an exposed pad provides a low thermal resistance path and a robust PCB land pattern suitable for automotive reflow profiles.
The device uses a MEMS sensing element and a BiCMOS signal chain for ratiometric analog-to-digital conversion, with internal clock and self-diagnostics. The SPI interface supports standard mode 0 (CPOL=0, CPHA=0) and mode 3, and the integrated low-pass filter can be adjusted via external capacitor for bandwidth tuning per application requirements.
Typical applications include automotive airbag systems, electronic stability control (ESC), vehicle dynamics control (VDC), rollover detection, and chassis attitude sensing. The medium-g over-damped response curve makes it particularly suitable for crash pulse measurement where clean low-frequency content is required.
When designing with this device, place the exposed pad over a continuous ground pour to provide thermal and mechanical stability. Maintain SPI trace length matching within 10 mm to avoid setup/hold violations at the maximum clock rate. Decouple VDD with a 100 nF ceramic capacitor placed within 2 mm of the supply pin.
This page synthesizes distributor pricing from DigiKey/LCSC/Heisener, drop-in alternatives from the MMA68xx family, automotive-grade substitution guidance, and PCB design notes not typically compiled in the NXP datasheet PDF.
Drop-in alternatives for MMA6813BKCWR2 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MMA6813BKCWR2 (same form factor and footprint) — differing in Output Type, Package, RoHS Status, Self-Test, Sensor Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MMA6801BKCWR2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MMA6821BKCWR2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MMA6851BKCWR2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MMA6861BKCWR2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MMA6811BKCWR2
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MMA6813BKCWR2 Maximum Ratings & Electrical Characteristics
| Sensor Type | Accelerometer, dual-axis (X, Y) lateral |
| Full-Scale Range | ±50 g |
| Output Type | Digital, 10-bit SPI |
| Interface | SPI (Mode 0 and Mode 3 compatible) |
| Supply Voltage | 3.3 V / 5 V |
| Axis Count | 2 (X, Y) |
| Self-Test | Yes (built-in) |
| Operating Temperature Range | -40 C to +125 C (automotive grade) |
| Package | 16-QFN (6x6 mm) with exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Safety Class | NXP SafeAssure solution |
| Application Domain | Automotive airbag, ESC, vehicle dynamics |
MMA6813BKCWR2 Pin Configuration
| Pin 1 | SCLK — SPI serial clock input |
| Pin 2 | MOSI — SPI master-out-slave-in (data input to sensor) |
| Pin 3 | MISO — SPI master-in-slave-out (data output from sensor) |
| Pin 4 | CS — Chip select (active low) |
| Pin 5 | VDD — Power supply (3.3 V or 5 V) |
| Pin 6 | GND — Ground reference |
| Pin 7 | RESET — Reset input (active low) |
| Pin 8 | INT — Interrupt output (active low) |
| Pin 9 | NC — Not connected |
| Pin 10 | X_TEST — X-axis self-test input |
| Pin 11 | Y_TEST — Y-axis self-test input |
| Pin 12 | NC — Not connected |
| Pin 13 | NC — Not connected |
| Pin 14 | NC — Not connected |
| Pin 15 | NC — Not connected |
| Pin 16 | NC — Not connected |
Typical Applications
MMA6813BKCWR2 is suitable for 6 applications: Automotive Airbag Crash Sensing, Electronic Stability Control (ESC), Vehicle Dynamics Control (VDC), Rollover Detection, Chassis Attitude / Tilt Sensing, Industrial Vibration Monitoring.
Automotive Airbag Crash Sensing
The MMA6813BKCWR2's ±50 g full-scale range and over-damped lateral response make it ideally suited for frontal and side airbag crash pulse measurement. Per the NXP MMA68xx datasheet, the over-damped mechanical transfer function suppresses high-frequency vibration noise that would otherwise corrupt the low-frequency crash event. The 10-bit SPI output provides ~0.1 g/LSB granularity at 50 g full-scale, sufficient for airbag discrimination algorithms. Placed at the vehicle center of gravity, it feeds the airbag control unit (ACU) with dual-axis lateral data to discriminate between deployment-worthy and non-deployment events, improving occupant safety while preventing unnecessary deployments.
Recommended
Electronic Stability Control (ESC)
The MMA6813BKCWR2 dual-axis lateral sensing provides the chassis attitude data needed by ESC systems to detect skidding and apply corrective braking. Its ±50 g range accommodates the dynamic accelerations seen during emergency maneuvers and ABS intervention events. The 16-QFN (6x6) exposed-pad package operates reliably from -40 C to +125 C, matching under-hood thermal stress. Placed near the vehicle center of mass, the sensor feeds lateral acceleration to the ESC ECU where it is combined with yaw-rate gyro data to compute vehicle sideslip. The SPI bus allows multi-sensor daisy-chaining, simplifying the ESC sensor cluster wiring harness.
Recommended
Vehicle Dynamics Control (VDC)
The MMA6813BKCWR2 measures chassis lateral dynamics for active suspension and roll-stability control applications. Its over-damped response (relative to lightly-damped MEMS sensors) provides the clean low-frequency content needed for control loop stability in VDC systems. The 50 g dynamic range captures hard cornering and evasive maneuvers without saturation. SPI digital output simplifies PCB routing and reduces analog noise pickup in noisy underbody environments. VDC systems use this sensor data to actively adjust suspension damping or apply individual wheel braking, improving ride comfort and reducing rollover risk in SUVs and light trucks.
Recommended
Rollover Detection
Rollover detection algorithms require accurate lateral acceleration data to identify vehicle tip-up events before they become critical. The MMA6813BKCWR2's ±50 g range and over-damped response provide the clean lateral acceleration signal needed to feed the rollover discrimination algorithm, which combines lateral g with roll rate to deploy curtain airbags and pretensioners. Its SafeAssure safety designation and automotive -40 C to +125 C operating range make it suitable for underbody mounting. The sensor's SPI digital output integrates with modern airbag control units that aggregate multiple sensor inputs over high-speed SPI buses.
Recommended
Chassis Attitude / Tilt Sensing
The MMA6813BKCWR2 dual-axis sensing provides chassis tilt and attitude data for headlight leveling, hill-start assist, and adaptive suspension systems. Its 50 g dynamic range far exceeds tilt-sensing requirements but provides robust immunity to vibration and shock transients that would saturate lower-range sensors. The 16-QFN (6x6) package measures only 6x6 mm, fitting in compact sensor modules behind the bumper or under the seat. Designers can use the 10-bit SPI output to compute static tilt angle from 1 g gravity vector and dynamic chassis motion from transient events simultaneously.
Recommended
Industrial Vibration Monitoring
Outside automotive, the MMA6813BKCWR2 serves industrial vibration monitoring on rotating machinery where 50 g peaks are common during fault events. Its over-damped transfer function matches industrial accelerometer requirements, suppressing resonance peaks that would otherwise trigger false alarms. The SPI digital output can be read directly by an industrial MCU without analog signal conditioning. The 16-QFN exposed pad provides -40 C to +125 C operation for outdoor enclosures and factory-floor thermal stress. Predictive maintenance algorithms use the dual-axis data to compute vibration magnitude and trend machine health.
Recommended
Recommended Products Summary
Engineering reference data for MMA6813BKCWR2 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MMA6801BKCWR2 | MMA6821BKCWR2 | MMA6851BKCWR2 | MMA6861BKCWR2 | MMA6811BKCWR2 |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 16-QFN (6x6) with exposed pad | 16-QFN (6x6) - same | 16-QFN (6x6) - same | 16-QFN (6x6) - same | 16-QFN (6x6) - same | 16-QFN (6x6) - same |
| Output Type | 10-bit SPI digital | 10-bit SPI digital - same | 10-bit SPI digital - same | 10-bit SPI digital - same | 10-bit SPI digital - same | 10-bit SPI digital - same |
| Axes | X, Y (dual-axis lateral) | X, Y - same | X, Y - same | X, Y - same | X, Y - same | X, Y - same |
| Interface | SPI (Mode 0/3) | SPI (Mode 0/3) - same | SPI (Mode 0/3) - same | SPI (Mode 0/3) - same | SPI (Mode 0/3) - same | SPI (Mode 0/3) - same |
| Supply Voltage | 3.3 V / 5 V | 3.3 V / 5 V - same | 3.3 V / 5 V - same | 3.3 V / 5 V - same | 3.3 V / 5 V - same | 3.3 V / 5 V - same |
| Operating Temperature | -40 C to +125 C | -40 C to +125 C - same | -40 C to +125 C - same | -40 C to +125 C - same | -40 C to +125 C - same | -40 C to +125 C - same |
Key Differentiators
- NXP SafeAssure safety designation (vs MMA6801BKCWR2)
- Over-damped response for clean low-frequency crash pulses (vs MMA6821BKCWR2)
- 50 g range as the sweet spot for frontal airbag sensing (vs MMA6851BKCWR2)
Design Notes
Place a 100 nF ceramic decoupling capacitor within 2 mm of the VDD pin (pin 5) and a 10 uF tantalum or ceramic bulk capacitor within 10 mm. The exposed thermal pad (EP) must be soldered to a continuous ground pour with at least 8 thermal vias (0.3 mm drill) to provide thermal dissipation and mechanical rigidity. Stencil aperture for the EP should be split into an array of smaller openings to reduce tombstoning during reflow.
Match SPI trace lengths (SCLK, MOSI, MISO, CS) within 10 mm to avoid setup/hold violations at the maximum clock rate. Keep SPI traces over a continuous reference ground plane; avoid routing across split planes or near noisy switching nodes. Place a 33 ohm series termination resistor at the SCLK source to damp reflections on long traces (>50 mm). Route MISO with controlled impedance if the bus exceeds 30 mm.
Do not exceed the absolute maximum VDD of 5.5 V; transient overvoltage events above this rating can permanently damage the MEMS element. The self-test pins (X_TEST, Y_TEST) must be left floating or tied to GND during normal operation; do not drive them with external logic unless invoking self-test mode. The INT pin is open-drain and requires an external pull-up to VDD. After power-up, allow at least 100 ms for the internal clock to stabilize before reading acceleration data.
Estimated: at ambient 85 C and typical 5 mA supply current, the MMA6813BKCWR2 dissipates ~25 mW. The exposed pad provides a thermal resistance (theta_JA) of approximately 35 C/W, giving a junction-to-ambient temperature rise of less than 1 C. Thermal performance is dominated by PCB copper pour area under the EP, not by the package itself. For underbody mounting where ambient can reach 125 C, ensure the EP copper area is at least 100 mm².
Compliance Information
AEC-Q100 qualified per NXP SafeAssure designation. RoHS and REACH compliant per NXP product page. Halogen-free and lead-free confirmed by NXP packaging materials disclosure. Conflict minerals compliant per NXP supply chain policy.