EVAL-AD7147EBZ Analog Devices Inc, EVAL-AD7147EBZ Datasheet - Page 2

• Manufacturer Part Number: EVAL-AD7147EBZ
• Description: BOARD EVAL FOR AD7147ACPZ
• Manufacturer: Analog Devices Inc
• Series: CapTouch™r

Specifications of EVAL-AD7147EBZ

• Sensor Type: Touch, Capacitive
• Interface: SPI Serial
• Voltage - Supply: 2.6 V ~ 3.6 V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: AD7147
• Silicon Manufacturer: Analog Devices
• Application Sub Type: CapTouch Controller
• Kit Application Type: Data Converter
• Silicon Core Number: AD7147
• Kit Contents: CapTouch Evaluation Board, USB Cable
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sensitivity: -
• Sensing Range: -
• Lead Free Status / Rohs Status: Compliant

AD7147
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
Capacitiance-to-Digital Converter ............................................... 14
Capacitance Sensor Input Configuration .................................... 17
Noncontact Proximity Detection ................................................. 18
Environmental Calibration ........................................................... 23
REVISION HISTORY
7/09—Rev. A to Rev. B
Changes to BIAS Pin Description .................................................. 8
Changes to BIAS Pin Section ........................................................ 12
8/08—Rev. 0 to Rev. A
Changes to Table 3 ............................................................................ 4
Added Figure 3, Renumbered Sequentially .................................. 6
Changes to Low Power Mode Section ......................................... 13
Average Current Specifications .................................................. 4
SPI Timing Specifications (AD7147) ......................................... 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 (AD7147-1) ..................................... 6
Rev. B | Page 2 of 72
Adaptive Threshold and Sensitivity ............................................. 26
Interrupt Output ............................................................................. 28
Outputs ............................................................................................ 32
Serial Interface ................................................................................ 33
PCB Design Guidelines ................................................................. 38
Power-Up Sequence ....................................................................... 39
Typical Application Circuits ......................................................... 40
Register Map ................................................................................... 41
Detailed Register Descriptions ..................................................... 42
Outline Dimensions ....................................................................... 69
Added Latency from Touch to Response Section ...................... 13
Added Low Latency from Touch to Response Section .............. 13
Changes to Figure 60 and Figure 61............................................. 40
Changes to Figure 62 ...................................................................... 41
Added Exposed Pad Notation to Outline Dimensions ............. 68
9/07—Revision 0: Initial Version
Capacitance Sensor Behavior Without Calibration ............... 23
Threshold Equations .................................................................. 24
Capacitance Sensor Behavior with Calibration ...................... 24
Slow FIFO .................................................................................... 24
SLOW_FILTER_UPDATE_LVL .............................................. 25
CDC Conversion-Complete Interrupt .................................... 28
Sensor-Touch Interrupt ............................................................. 28
GPIO INT Output Control ....................................................... 30
AC
General-Purpose Input/Output (GPIO) ................................. 32
Using the GPIO to Turn On/Off an LED ................................ 32
SPI Interface ................................................................................ 33
I
V
Capacitive Sensor Board Mechanical Specifications ............. 38
Chip Scale Packages ................................................................... 38
Bank 1 Registers ......................................................................... 42
Bank 2 Registers ......................................................................... 52
Bank 3 Registers ......................................................................... 57
Ordering Guide .......................................................................... 69
2
C-Compatible Interface .......................................................... 35
DRIVE
SHIELD
Input ................................................................................. 37
Output .......................................................................... 32