AD7877 Analog Devices, AD7877 Datasheet - Page 2

• Manufacturer Part Number: AD7877
• Description: Touch Screen Controller
• Manufacturer: Analog Devices

Specifications of AD7877

• Resolution (bits): 12bit
• # Chan: 9
• Sample Rate: 125kSPS
• Interface: Ser
• Analog Input Type: SE-Uni
• Ain Range: Uni (Vref),Uni 2.5V
• Adc Architecture: SAR
• Pkg Type: CSP

AD7877
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 6
Pin Configurations and Function Descriptions ........................... 7
Typical Performance Characteristics ............................................. 9
Terminology .................................................................................... 13
Circuit Information ........................................................................ 14
REVISION HISTORY
12/11—Rev. C to Rev. D
Change to Features Section ............................................................. 1
Updated Outline Dimensions ....................................................... 44
Changes to Ordering Guide .......................................................... 44
Added Automotive Products Section .......................................... 44
9/09—Rev. B to Rev. C
Changes to Offset Error and Gain Error Parameters .................. 3
Added V
Changes to Pin 23 Description ....................................................... 7
Changes to Power Management (Control Register 2,
Bits[7:6]) Section ............................................................................ 22
Changes to Bit 7 Description (Table 17) ...................................... 36
Updated Outline Dimensions ....................................................... 44
Changes Ordering Guide ............................................................... 44
6/06—Rev. A to Rev. B
Added Wafer Level Chip Scale Package ........................... Universal
Changes to Table 3 ............................................................................ 6
Timing Specifications .................................................................. 5
Timing Diagrams .......................................................................... 5
ESD Caution .................................................................................. 6
Touch Screen Principles ............................................................ 14
Measuring Touch Screen Inputs ............................................... 15
Touch-Pressure Measurement .................................................. 16
STOPACQ Pin ............................................................................ 16
Temperature Measurement ....................................................... 17
Battery Measurement ................................................................. 18
Auxiliary Inputs .......................................................................... 19
Limit Comparison ...................................................................... 19
BAT
to GND Parameter ...................................................... 6
Rev. D | Page 2 of 44
Control Registers ............................................................................ 20
8-Bit DAC ........................................................................................ 26
Serial Interface ................................................................................ 28
General-Purpose I/O Pins ............................................................. 30
Grounding and Layout .................................................................. 32
Register Maps .................................................................................. 33
Detailed Register Descriptions ..................................................... 35
Outline Dimensions ....................................................................... 44
Changes to Figure 21 ...................................................................... 11
Change to Figure 25 ....................................................................... 12
Changes to Figure 38 and Figure 39............................................. 23
Change to Figure 40 ....................................................................... 24
Changes to Data Available Output ( DAV ) Section .................... 24
Updated Outline Dimensions ....................................................... 42
Changes to Ordering Guide .......................................................... 42
11/04—Rev. 0 to Rev. A
Changes to Absolute Maximum Ratings ....................................... 6
Changes to Figure 4 ........................................................................... 7
Changes to Table 4 ............................................................................. 7
Changes to Grounding and Layout section ................................ 32
Changes to Figure 42 ...................................................................... 32
Changes to Ordering Guide .......................................................... 43
7/04—Revision 0: Initial Version
Control Register 1 ...................................................................... 20
Control Register 2 ...................................................................... 21
Sequencer Registers ................................................................... 22
Interrupts ..................................................................................... 24
Syncronizing the AD7877 to the Host CPU ........................... 25
Writing Data ............................................................................... 28
Write Timing ............................................................................... 29
Reading Data ............................................................................... 29
V
GPIO Configuration .................................................................. 30
PCB Design Guidelines for Chip Scale Packages ................... 32
GPIO Registers ........................................................................... 42
Ordering Guide .......................................................................... 44
Automotive Products ................................................................. 44
DRIVE
Pin ..................................................................................... 29
Data Sheet