Capacitive accelerometer

Overview

Memsic's capacitive accelerometers are 3-axis digital sensors with the sensor and circuits built on one chip in a standard CMOS process. Memsic says the technology has shipped in more than 600 million units. Many parts offer sniff and ultra-low-power modes that let the sensor wake a host system while drawing well under a microamp to a few microamps.

Built for

Vehicle smart keys and door drives
Wearables and trackers
Smartphones and tablets
Medical and smart home devices

Key features

Monolithic CMOS

The sensor and circuits are integrated on a standard CMOS process for small size.

Sniff and wake modes

Sniff modes draw as little as 0.25 to 0.4 µA, with low-power wake modes from 0.9 µA at 25 Hz.

FIFO buffering

Most parts have a FIFO, from 32 samples up to 1.5 KB on the MXC3500AL.

Selectable ranges

Ranges run from ±2 g to ±16 g, and the MXC3500AL adds ±24 g.

I2C and SPI

I2C runs up to 1 MHz, and SPI up to 8 or 10 MHz on parts that offer it.

Automotive option

The MXC3638AL is listed as AEC-Q100 Class 3 for vehicle smart key use.

Specifications

Technology: Capacitive MEMS, monolithic CMOS
Axes: 3
Range: ±2 g to ±16 g (±24 g on MXC3500AL)
Resolution: 8 to 16-bit, by part
Output data rate: Up to 4000 Hz, by part
Interface: I2C up to 1 MHz, SPI up to 10 MHz
Lowest sniff current: 250 nA at 2 Hz (MXC3500AL)
FIFO: 32 samples to 1.5 KB
Smallest listed package: 1.6 x 1.6 x 0.94 mm (MC3635)
Mass production: Over 600 million units (Memsic)

Part numbers (link to datasheets)

Part	Axes	Range	Resolution / FIFO	Max ODR	Interface	Package	Notes
MXC3638AL	3	±2, 4, 8, 12, 16 g	8/10/12-bit, 32-sample FIFO	1300 Hz	I2C 1 MHz, SPI 8 MHz	2.0 x 2.0 x 0.94 mm, 12-pin	AEC-Q100 Class 3, 0.4 µA sniff at 6 Hz
MXC3500AL	3	±2, 4, 8, 12, 16, 24 g	16-bit, 1.5 KB FIFO	4000 Hz	I2C 1 MHz, SPI 10 MHz	2.0 x 2.0 x 0.73 mm, 12-pin	250 nA sniff at 2 Hz, 0.84 mg RMS noise
MC3416	3	±2, 4, 8, 12, 16 g	16-bit	1024 Hz	I2C 1 MHz	LGA 2 x 2 x 0.92 mm, 12-pin	4 µA standby
MC3419	3	±2, 4, 8, 12, 16 g	16-bit with FIFO	2000 Hz	I2C 1 MHz, SPI 10 MHz	LGA 2 x 2 x 0.92 mm, 12-pin	4 µA standby
MC3479	3	±2, 4, 8, 12, 16 g	16-bit with FIFO	2000 Hz	I2C 1 MHz, SPI 10 MHz	LGA 2 x 2 x 0.92 mm, 12-pin	4 µA standby
MC3630	3	±2, 4, 8, 12, 16 g	8/10/12-bit, 32-sample FIFO	1300 Hz	I2C 1 MHz, SPI 8 MHz	2.0 x 2.0 x 0.94 mm, 12-pin	0.4 µA sniff at 6 Hz, 0.9 µA at 25 Hz
MC3632	3	±2, 4, 8, 12, 16 g	8/10/12-bit, 32-sample FIFO	1300 Hz	I2C 1 MHz, SPI 8 MHz	LGA 2.0 x 2.0 x 0.94 mm, 12-pin	0.4 µA sniff at 1 Hz, 2.0 µA at 25 Hz
MC3635	3	±2, 4, 8, 12, 16 g	8/10/12-bit, 32-sample FIFO	1300 Hz	I2C 1 MHz, SPI 8 MHz	1.6 x 1.6 x 0.94 mm, 10-pin	0.3 µA sniff at 1 Hz