ADI ADXL362微功耗三轴MEMS加速度计解决方案

发布时间:2012-6-21 12:23    发布者:1770309616
关键词: ADI , ADXL362 , MEMS , 加速度计
ADI公司的ADXL362是微功耗三轴MEMS加速度计,数字输出,加速度范围为±2/±4/±8 g, 工作电压1.8V-3.3V,电源电压2V和100Hz输出数据速率时的功耗为2μA,运动触发叫醒模式的功耗为300nA,器件提供12位输出分辨率,8位格式的数据,在±2 g范围的分辨率为1 mg/LSB,主要用在助听器,家庭保健设备,运动使能电源开关,无线传感器和运动使能计量设备.本文介绍了ADXL362主要特性, ADXL362功能方框图以及评估板EVAL-ADXL362Z主要特性和电路图.

ADXL362器件不同于其他加速度计,使用功率负载循环以实现低功耗,ADXL362器件并不通过低采样来混淆输入信号,它对传感器的全带宽,所有的数据速率进行采样。

ADXL362一直提供12位的输出分辨率,当较低的分辨率足够时,ADXL362还提供8位格式的数据用于更有效的单字节传输。其测量范围为±2g,±4 g,±8g,其±2 g范围内的分辨率为1 mg/LSB。 在噪音要求低于ADXL362的正常550μg/7Hz时,可以任意选择一个低噪音模式(低于175μg/7Hz典型),其电源电流增加小。

除了其超低的功耗,ADXL362还具有许多功能,使其系统级功耗降低。

该器件包括了多模输出FIFO,一个内置的微功率温度传感器,和几个活动检测模式,包括,可调阈值睡眠和唤醒操作,可以在300 nA ,6Hz(近似)测量速率运行。如果需要,它的一个引脚输可直接控制外部开关。此外,DXL362还具有采样时间或外部时钟的外部控制。


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图1 ADXL362功能方框图
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图2 评估板EVAL-ADXL362Z电路

ADXL362具有宽电源电压范围,1.6 V~3.6 V。如有必要,可以接口连接一个单独的,更低的电源电压。 ADXL362为3mm×3.25mm×1.06mm封装。

ADXL362主要特性

•超低功耗

•电力可以来自纽扣电池

• 1.8μA,100Hz ODR,2.0V供电

• 3.0μA,400Hz ODR,2.0V供电

• 300nA运动激活唤醒模式

• 10nA的待机电流

•系统级内置省电功能

–运动激活可调阈值睡眠/唤醒模式

–自治中断处理,而不需要微控制器的干预,使系统其余部分完全关闭

–深嵌入式FIFO减少主机处理器的负载

•最低噪音175 μg/Hz

•宽电源电压和I/O电压范围:1.6 V~3.6 V

•可用1.8V~3.3V电源轨

•通过外部触发,加速采样同步

•片上温度传感器

• SPI数字接口

•通过SPI命令选择测量范围

•小而薄的3mm×3.25mm×1.06mm封装

ADXL362应用

•助听器

•家庭医疗保健设备

•运动启动的节电开关

•无线传感器

•运动启动的计量装置
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图3 评估板EVAL-ADXL362Z卫星板电路图

评估板EVAL-ADXL362Z

EVAL-ADXL362Z是一个简单的接口板,可以将ADXL362微功率,3轴,数字输出MEMS加速度计,轻松连接到现有的系统。由于其体积小,EVAL-ADXL362Z对系统的性能和加速度计的影响很小,因此,它是现有的系统ADXL362评估的理想选择。需要注意,ADXL362必须通过SPI进行数字通信。EVAL-ADXL362Z没有处理器,外部固件必须由用户提供。

EVAL-ADXL362Z-MLP是一个完整的系统,用于ADXL362微功率,3轴,数字输出MEMS加速度计的实时评价。该系统具有图形用户界面(GUI),便于评价参数,如功耗,温度系数,噪声等。该系统包括一个主板和一个卫星板。传感器被安置在卫星板上的插座上,使得一个评估体系可以进行多个部件的评估。

如要完整的系统,请订购EVAL-ADXL362Z-MLP。此套件包括主板,卫星电路板,加速度计和电缆。使用零件编号EVAL-ADXL362Z-S,可以订购卫星电路板套件。卫星套件订单包括卫星电路板和加速度计。

ADXL362: Micropower 3-Axis MEMS Accelerometer: Digital Output, ±2/±4/±8 g Range

The ADXL362 is an ultra-low power 3-axis MEMS accelerometer that consumes less than 2 μA at a 100 Hz output data rate, and 300 nA in motion-triggered Wake-Up Mode.

Unlike accelerometers that use power duty cycling to achieve low power consumption, the ADXL362 does not alias input signals by undersampling; it samples the sensor’s full bandwidth at all data rates.

The ADXL362 always provides 12-bit output resolution; 8-bit formatted data is also provided for more efficient single-byte transfers when a lower resolution is sufficient. Measurement ranges of ±2 g, ±4 g, and ±8 g are available, with a resolution of 1 mg/LSB on the ±2 g range. For applications where a noise level lower than the ADXL362’s normal 550 μg/7Hz is desired, either of two lower noise modes (down to 175 μg/7Hz typ) may be selected at minimal increase in supply current.

In addition to its ultra-low power consumption, the ADXL362 has many features to enable true system-level power reduction.

It includes a deep multimode output FIFO, a built-in micropower temperature sensor, and several activity detection modes including adjustable-threshold sleep and wakeup operation that can run as low as 300 nA at a 6 Hz (approximate) measurement rate. A pin output is provided to directly control an external switch when activity is detected if desired. In addition, the ADXL362 has provisions for external control of sampling time and/or an external clock.

The ADXL362 operates on a wide 1.6 V to 3.6 V supply range, and can interface, if necessary, to a host operating on a separate, lower supply voltage. The ADXL362 is available in a 3 mm × 3.25 mm × 1.06 mm package.

ADXL362主要特性:

Ultra low power

Power can be derived from coin cell battery

1.8 μA @ 100 Hz ODR, 2.0V supply

3.0 μA @ 400 Hz ODR, 2.0V supply

300 nA motion-activated Wake-up Mode

10nA Standby Current

Built-in features for system-level power savings:

Adjustable-threshold sleep/wake modes for motion activation

Autonomous interrupt processing without need for microcontroller intervention, so the rest of the system can be turned off completely

Deep embedded FIFO minimizes host processor load

Awake state output enables implementation of standalone motion-activated switch High resolution of 1 mg/LSB

Low noise down to 175 μg/@Hz

Wide supply and I/O voltage ranges: 1.6 V to 3.6 V

Operates off 1.8V to 3.3V rails

Acceleration sample synchronization via external trigger

On-chip temperature sensor

SPI digital interface

Measurement ranges selectable via SPI command

Small and thin 3 mm × 3.25 mm × 1.06 mm package

ADXL362应用:

Hearing aids

Home healthcare devices

Motion-enabled power save switch

Wireless sensors

Motion-enabled metering devices
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图1. ADXL362功能方框图

ADXL362评估板EVAL-ADXL362Z

The EVAL-ADXL362Z is a simple breakout board that enables easy connection of an ADXL362 micropower, 3-axis, digital-output MEMS accelerometer into an existing system. Due to its small size, the EVAL-ADXL362Z has minimal effect on performance of the system and of the accelerometer, and thus it is ideal for evaluation of the ADXL362 in an existing system. Note that the ADXL362 must be communicated with digitally via SPI. No processor is included with the EVAL-ADXL362Z; firmware must be supplied externally by the user. Some sample firmware is available at the link below:

The EVAL-ADXL362Z-MLP is a complete system for real-time evaluation of the ADXL362 micropower, 3-axis, digital-ouptut MEMS accelerometer. This system is accompanied by a graphical user interface (GUI) that facilitates evaluation of parameters such as power consumption, temperature coefficient, noise, and more. The system consists of a motherboard and a satellite board. The sensor is housed in a socket on the satellite board, enabling evaluation of multiple parts using one evaluation system.

To order the complete system, order the EVAL-ADXL362Z-MLP. This kit includes a motherboard, satellite board, accelerometer, and cables. Additional satellite board kits can be ordered using the part number EVAL-ADXL362Z-S. Satellite kit orders include a satellite board and an accelerometer.

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图2. 评估板EVAL-ADXL362Z外形图
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图3.评估板EVAL-ADXL362Z电路图
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图4.评估板EVAL-ADXL362Z卫星板电路图
详情请见:
ADXL362[1].pdf (876.21 KB)
Motherboard_Schematic[1].pdf (143.2 KB) 以及
Satellite_Board_Schematic[1].pdf (67.77 KB)

来源;网络
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