Datasheet

AD7291 Data Sheet
Rev. B | Page 2 of 28
TABLE OF CONTENTS
Features .............................................................................................. 1
Functional Block Diagram .............................................................. 1
General Description......................................................................... 1
Product Highlights ........................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
I
2
C Timing Specifications............................................................ 5
Absolute Maximum Ratings............................................................ 6
Thermal Resistance ...................................................................... 6
ESD Caution.................................................................................. 6
Pin Configuration and Function Descriptions............................. 7
Typical Performance Characteristics ............................................. 8
Terminology .................................................................................... 11
Circuit Information........................................................................ 12
Converter Operation.................................................................. 12
Analog Input ............................................................................... 12
ADC Transfer Function............................................................. 13
Temperature Sensor Operation ................................................ 13
Temperature Sensor Averaging................................................. 13
V
DRIVE
............................................................................................ 14
The Internal or External Reference.......................................... 14
Reset ............................................................................................. 14
Internal Register Structure ............................................................ 15
Address Pointer Register ........................................................... 15
Command Register (0x00)........................................................ 17
Voltage Conversion Result Register (0x01) ............................ 18
T
SENSE
Conversion Result Register (0x02)................................ 18
T
SENSE
Average Result Register (0x03)...................................... 19
Limit Registers (0x04 to 0x1E) ................................................. 19
Hysteresis Register ..................................................................... 20
Alert Status Register A and Alert Status Register B (0x1F and
0x20)............................................................................................. 20
I
2
C Interface .................................................................................... 21
Serial Bus Address Byte ............................................................. 21
General I
2
C Timing.................................................................... 21
Writing to the AD7291 .................................................................. 22
Writing Two Bytes of Data to a 16-Bit Register ..................... 22
Writing to Multiple Registers.................................................... 22
Reading Data From the AD7291.................................................. 23
Reading Two Bytes of Data from a 16-Bit Register ............... 23
Modes of Operation ....................................................................... 24
Command Mode ........................................................................ 24
Autocycle Mode.......................................................................... 26
Outline Dimensions ....................................................................... 27
Ordering Guide .......................................................................... 27
REVISION HISTORY
10/11—Rev. A to Rev. B
Changes to Table 9.......................................................................... 16
8/11—Rev. 0 to Rev. A
Changes to Temperature Sensor—Internal, Accuracy Parameter,
Table 2 ................................................................................................ 3
1/11—Revision 0: Initial Version