ad7147a-1acbz-r Analog Devices, Inc., ad7147a-1acbz-r Datasheet - Page 2

• Manufacturer Part Number: ad7147a-1acbz-r
• Description: Captouch Programmable Controller For Single-electrode Capacitance Sensors
• Manufacturer: Analog Devices, Inc.

AD7147A
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 7
Pin Configurations and Function Descriptions ........................... 8
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 11
Capacitance-to-Digital Converter ................................................ 14
Capacitance Sensor Input Configuration .................................... 17
Noncontact Proximity Detection ................................................. 18
Environmental Calibration ........................................................... 23
REVISION HISTORY
1/09—Revision 0: Initial Version
Average Current Specifications .................................................. 4
SPI Timing Specifications (AD7147A) ...................................... 5
I
ESD Caution .................................................................................. 7
Capacitance Sensing Theory ..................................................... 11
BIAS Pin ....................................................................................... 12
Operating Modes ........................................................................ 12
Oversampling the CDC Output ............................................... 14
Capacitance Sensor Offset Control .......................................... 14
Conversion Sequencer ............................................................... 14
CDC Conversion Sequence Time ............................................ 16
CDC Conversion Results ........................................................... 16
CINx Input Multiplexer Setup .................................................. 17
Single-Ended Connections to the CDC .................................. 17
Recalibration ............................................................................... 18
Proximity Sensitivity .................................................................. 18
FF_SKIP_CNT ............................................................................ 21
2
C Timing Specifications (AD7147A-1) .................................. 6
Rev. 0 | Page 2 of 68
Adaptive Threshold and Sensitivity ............................................. 25
Interrupt Output ............................................................................. 27
Outputs ............................................................................................ 31
Serial Interfaces ............................................................................... 32
PCB Design Guidelines ................................................................. 37
Power-Up Sequence ....................................................................... 38
Typical Application Circuits ......................................................... 39
Register Map ................................................................................... 40
Detailed Register Descriptions ..................................................... 41
Outline Dimensions ....................................................................... 68
Capacitance Sensor Behavior Without Calibration ............... 23
Threshold Equations .................................................................. 23
Capacitance Sensor Behavior with Calibration ...................... 24
Slow FIFO .................................................................................... 24
SLOW_FILTER_UPDATE_LVL .............................................. 24
CDC Conversion-Complete Interrupt .................................... 27
Sensor-Touch Interrupt ............................................................. 27
GPIO INT Output Control ....................................................... 29
AC
General-Purpose Input/Output (GPIO) ................................. 31
Using the GPIO to Turn On/Off an LED ................................ 31
SPI Interface ................................................................................ 32
I
V
Capacitive Sensor Board Mechanical Specifications ............. 37
WLCSP Package ......................................................................... 37
Bank 1 Registers ......................................................................... 41
Bank 2 Registers ......................................................................... 51
Bank 3 Registers ......................................................................... 56
Ordering Guide .......................................................................... 68
2
C-Compatible Interface .......................................................... 34
DRIVE
SHIELD
Input ................................................................................. 36
Output .......................................................................... 31