Analog Devices: CN0274 Reference Design for Ultralow Power Standalone Motion Switch

atomar — Tue, 23 Apr 2013 06:36:20 GMT

Current Revision posted to Documents by atomar on 4/23/2013 6:36:20 AM

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Kit Overview

The Analog Devices EVAL-CN0274-SDPZEVAL-CN0274-SDPZ Evaluation Board Circuit provides an ultralow power, 3-axis, motion activated power switch solution capable of controlling up to 1.1 A of load current. The circuit is ideal for applications where extended battery life is critical. When the switch is off, the battery current is less than 300 nA, and when the switch is on, it draws less than 3 μA. The circuit provides an industry leading, low power motion sensing solution suitable for wireless sensors, metering devices, home healthcare, and other portable applications.

The ADXL362ADXL362 is an ultralow power, 3-axis accelerometer that consumes less than 100 nA in wake-up mode. Unlike accelerometers that use power duty cycling to achieve low power consumption, the ADXL362 does not alias input signals by under sampling; it samples continuously at all data rates. There is also an on-chip, 12-bit temperature sensor accurate to ±0.5°.

The ADXL362ADXL362 provides 12-bit output resolution and has three operating ranges, ±2 g, ±4 g, and ±8 g. It is specified over a minimum temperature range of −40°C to +85°C. For applications where a noise level less than 480 μg/√Hz is desired, either of its two lower noise modes (down to 120 μg/√Hz) can be selected at a minimal increase in supply current.

The ADP195 is a high-side load switch designed for operation between 1.1 V and 3.6 V and is protected against reverse current flow from output to input. The device contains a low on-resistance, P-channel MOSFET that supports over 1.1 A of continuous load current and minimizes power losses.

This circuit uses the EVAL-SDP-CS1ZEVAL-SDP-CS1Z (should be purchased seperately) System Demonstration Platform (SDP-S) evaluation board and the EVAL-CN0274-SDPZEVAL-CN0274-SDPZ circuit board. The two boards have 120-pin mating connectors, allowing for the quick setup and evaluation of the performance of the circuit.

The EVAL-CN0274-SDPZEVAL-CN0274-SDPZ contains the circuit to be evaluated and the EVAL-SDP-CS1ZEVAL-SDP-CS1Z is used with the CN0274 evaluation software to capture the data from the EVAL-CN0274-SDPZ. Because the ADXL362 requires a relatively small amount of power in both the asleep and awake states, it is possible to power the EVAL-CN0274-SDPZ from the digital data lines coming out of the EVAL-SDP-CS1ZEVAL-SDP-CS1Z.

Key Applications: Access Control, Asset Tracking, Home Healthcare, Patient Monitoring

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Development Tools

PC with a USB port and Windows® XP or Windows Vista® (32-bit), or Windows® 7 (32-bit)
EVAL-CN0274-SDPZEVAL-CN0274-SDPZ circuit evaluation board
EVAL-SDP-CS1ZEVAL-SDP-CS1Zcontroller board
- USB to Serial Engine
- 1 xsmall footprint 120 Pin Connector
- Configurable interface ( SPI, I2C, GPIO)
- USB 2.0 interface to the PC

CN0274 evaluation software
A power supply: 3.0 V or 2 AAA batteries

Technical Documents

Learning Center

Type	Description
User Manual	ADI: User Manual for CN-0274 Ultralow Power, 3-Axis, Motion Activated Switch
User Guide	ADI: User Guide for EVAL-SDP-CB1Z
User Guide	ADI: Getting Started with SDP
Datasheet	ADI: Data Sheet for ADSP-BF527 - Blackfin Embedded Processor
Datasheet	ADI: Datasheet for ADXL362 - Micropower Three-Axis, 2g/4g/8g Digital-Output MEMS Accelerometer (Rev A)
Datasheet	ADI: Datasheet for ADP195 - Logic Controlled, High-Side Power Switch with Reverse Current Blocking (Rev C)

Design Elements

Type	Description
Schematics	ADI: Schematics for EVAL-CN0274-SDPZ Evaluation Board
BOM	ADI: Bill Of Material (BOM) for EVAL-CN0274-SDPZ Evaluation Board
Layout	ADI: Layout for EVAL-CN0274-SDPZ
Application Library	ADI: Software Code for ADXL362 Generic Driver
Application Library	ADI: Software Code for ADXL362 PIC32 Driver
Application Library	ADI: Software Code for ADXL362 DSPIC33 Driver
Application Library	ADI: Software Code for ADXL362 chipKIT Driver

Video

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Kit Features

Key Features for ADXL362ADXL362 are as below:

Ultralow power
Power can be derived from coin cell battery
- 1.8 μA @ 100 Hz ODR, 2.0 V supply
- 3.0 μA @ 400 Hz ODR, 2.0 V supply
270 nA motion activated wake-up mode
10 nA standby current
High resolution: 1 mg/LSB
Built-in features for system-level power savings:
- Adjustable threshold sleep/wake modes for motion activation
- Autonomous interrupt processing, without need for microcontroller intervention, to allow the rest of the system to be turned off completely
- Deep embedded FIFO minimizes host processor load
- Awake state output enables implementation of standalone, motion activated switch
Low noise down to 175 ƒÊg/�ãHz
Wide supply and I/O voltage ranges: 1.6 V to 3.5 V
- Operates off 1.8 V to 3.3 V rails
Acceleration sample synchronization via external trigger
On-chip temperature sensor
SPI digital interface
Measurement ranges selectable via SPI command

Key Features for ADP195 are as below:

Ultralow on resistance (RDSON)
50 mΩ @ 3.6 V, 55 mΩ @ 2.5 V, 65 mΩ @ 1.8 V, 100 mΩ @ 1.2 V
Input voltage range: 1.1 V to 3.6 V
1.1 A maximum continuous operating current
Low enable control logic threshold can be operated from 1.2 V to 3.3 V
Low 1 μA (typical) ground current @ 1.8 V
Low 4 μA (maximum) reverse current @ 3.6 V
Ultralow shutdown current: 0.7 μA (typical) @ 1.8 V
Reverse current blocking

Kit Contents

The Analog Devices EVAL-CN0274-SDPZEVAL-CN0274-SDPZ kit is supplied with below contents:

Evaluation Board

Tags: adxl362, eval-cn0274-sdpz, adp195, analog_devices