
AD7997/AD7998
TABLE OF CONTENTS
Rev. 0 | Page 2 of 32
AD7997 Specifications.....................................................................3
AD7998 Specifications.....................................................................5
I
2
C Timing Specifications................................................................7
Absolute Maximum Ratings............................................................9
ESD Caution..................................................................................9
Pin Configuration and Pin Function Descriptions....................10
Terminology....................................................................................11
Typical Performance Characteristics...........................................12
Circuit Information........................................................................15
Converter Operation..................................................................15
Typical Connection Diagram ...................................................16
Analog Input...............................................................................16
Internal Register Structure............................................................18
Address Pointer Register ...........................................................18
Configuration Register..............................................................19
Conversion Result Register.......................................................20
Limit Registers............................................................................20
Alert Status Register (CH1 to CH4) ........................................21
Cycle Timer Register..................................................................22
Sample Delay and Bit Trial Delay.............................................22
Serial Interface ................................................................................23
Serial Bus Address...................................................................... 23
Writing to the AD7997/AD7998.................................................. 24
Writing to the Address Pointer Register for a Subsequent
Read.............................................................................................. 24
Writing a Single Byte of Data to the Alert Status Register or
Cycle Register.............................................................................. 24
Writing Two Bytes of Data to a Limit, Hysteresis, or
Configuration Register.............................................................. 24
Reading Data from the AD7997/AD7998................................... 26
ALERT/BUSY Pin .......................................................................... 27
SMBus ALERT............................................................................ 27
BUSY............................................................................................ 27
Placing the AD7997-1/AD7998-1 into High Speed Mode... 27
The Address Select (AS) Pin..................................................... 27
Modes of Operation....................................................................... 28
Mode 1—Using the CONVST Pin........................................... 28
Mode 2 – COMMAND MODE ............................................... 29
Mode 3—Automatic Cycle Interval Mode.............................. 30
Outline Dimensions....................................................................... 31
Ordering Guide .......................................................................... 31
Related Parts in I
2
C-Compatible ADC Product Family........ 31
REVISION HISTORY
9/04—Revision 0: Initial Version