AD7147WPACPZ-1RL(RevD) View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

AD7147WPACPZ-1RL
(Rev.:RevD)

CapTouch Programmable Controller for Single-Electrode Capacitance Sensors

Analog Devices 

AD7147

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications....................................................................................... 1

General Description ......................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 3

Specifications..................................................................................... 4

Average Current Specifications .................................................. 5

SPI Timing Specifications (AD7147)......................................... 6

I2C Timing Specifications (AD7147-1) ..................................... 7

Absolute Maximum Ratings............................................................ 8

ESD Caution.................................................................................. 8

Pin Configurations and Function Descriptions ........................... 9

Typical Performance Characteristics ........................................... 10

Theory of Operation ...................................................................... 12

Capacitance Sensing Theory..................................................... 12

BIAS Pin....................................................................................... 13

Operating Modes........................................................................ 13

Capacitiance-to-Digital Converter............................................... 15

Oversampling the CDC Output ............................................... 15

Capacitance Sensor Offset Control.......................................... 15

Conversion Sequencer ............................................................... 15

CDC Conversion Sequence Time ............................................ 17

CDC Conversion Results........................................................... 17

Capacitance Sensor Input Configuration.................................... 18

CINx Input Multiplexer Setup .................................................. 18

Single-Ended Connections to the CDC .................................. 18

Noncontact Proximity Detection ................................................. 19

Recalibration ............................................................................... 19

Proximity Sensitivity .................................................................. 19

FF_SKIP_CNT............................................................................ 22

Environmental Calibration ........................................................... 24

Data Sheet

Capacitance Sensor Behavior Without Calibration............... 24

Threshold Equations.................................................................. 25

Capacitance Sensor Behavior with Calibration...................... 25

Slow FIFO.................................................................................... 25

SLOW_FILTER_UPDATE_LVL .............................................. 26

Adaptive Threshold and Sensitivity ............................................. 27

Interrupt Output............................................................................. 29

CDC Conversion-Complete Interrupt .................................... 29

Sensor-Touch Interrupt ............................................................. 29

GPIO INT Output Control ....................................................... 31

Outputs ............................................................................................ 33

ACSHIELD Output .......................................................................... 33

General-Purpose Input/Output (GPIO) ................................. 33

Using the GPIO to Turn On/Off an LED................................ 33

Serial Interface ................................................................................ 34

SPI Interface ................................................................................ 34

I2C-Compatible Interface .......................................................... 36

VDRIVE Input ................................................................................. 38

PCB Design Guidelines ................................................................. 39

Capacitive Sensor Board Mechanical Specifications ............. 39

Chip Scale Packages ................................................................... 39

Power-Up Sequence ....................................................................... 40

Typical Application Circuits ......................................................... 41

Register Map ................................................................................... 42

Detailed Register Descriptions ..................................................... 43

Bank 1 Registers ......................................................................... 43

Bank 2 Registers ......................................................................... 53

Bank 3 Registers ......................................................................... 58

Outline Dimensions ....................................................................... 70

Ordering Guide .......................................................................... 70

Automotive Products ................................................................. 70

Rev. D | Page 2 of 72

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