AD5933 Data Sheet
Rev. E | Page 2 of 40
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 3
Specifications ..................................................................................... 4
I
2
C Serial Interface Timing Characteristics .............................. 6
Absolute Maximum Ratings ............................................................ 7
ESD Caution .................................................................................. 7
Pin Configuration and Descriptions .............................................. 8
Typical Performance Characteristics ............................................. 9
Terminology .................................................................................... 12
System Description ......................................................................... 13
Transmit Stage ............................................................................. 14
Frequency Sweep Command Sequence ................................... 15
Receive Stage ............................................................................... 15
DFT Operation ........................................................................... 15
System Clock ............................................................................... 16
Temperature Sensor ................................................................... 16
Temperature Conversion Details .............................................. 16
Temperature Value Register ...................................................... 16
Temperature Conversion Formula ........................................... 16
Impedance Calculation .................................................................. 17
Magnitude Calculation .............................................................. 17
Gain Factor Calculation ............................................................ 17
Impedance Calculation Using Gain Factor ............................. 17
Gain Factor Variation with Frequency .................................... 17
Two-Point Calibration ............................................................... 18
Two-Point Gain Factor Calculation ......................................... 18
Gain Factor Setup Configuration ............................................. 18
Gain Factor Recalculation ......................................................... 18
Gain Factor Temperature Variation ......................................... 19
Impedance Error ......................................................................... 19
Measuring the Phase Across an Impedance ........................... 19
Performing a Frequency Sweep .................................................... 22
Register Map ................................................................................... 23
Control Register (Register Address 0x80, Register Address
0x81) ............................................................................................. 23
Start Frequency Register (Register Address 0x82, Register
Address 0x83, Register Address 0x84) .................................... 24
Frequency Increment Register (Register Address 0x85,
Register Address 0x86, Register Address 0x87) ..................... 25
Number of Increments Register (Register Address 0x88,
Register Address 0x89) .............................................................. 25
Number of Settling Time Cycles Register (Register Address
0x8A, Register Address 0x8B) ................................................. 25
Status Register (Register Address 0x8F) .................................. 26
Temperature Data Register (16 Bits—Register Address 0x92,
Register Address 0x93) .............................................................. 26
Real and Imaginary Data Registers (16 Bits—Register
Address 0x94, Register Address 0x95, Register Address 0x96,
Register Address 0x97) .............................................................. 26
Serial Bus Interface ......................................................................... 27
General I
2
C Timing .................................................................... 27
Writing/Reading to the AD5933 .............................................. 28
Block Write .................................................................................. 28
Read Operations ......................................................................... 29
Typical Applications ....................................................................... 30
Measuring Small Impedances ................................................... 30
Biomedical: Noninvasive Blood Impedance Measurement .. 32
Sensor/Complex Impedance Measurement ............................ 32
Electro-Impedance Spectroscopy ............................................. 33
Layout and Configuration ............................................................. 34
Power Supply Bypassing and Grounding ................................ 34
Evaluation Board ............................................................................ 35
Using the Evaluation Board ...................................................... 35
Prototyping Area ........................................................................ 35
Crystal Oscillator (XO) vs. External Clock ............................. 35
Schematics ................................................................................... 36
Outline Dimensions ....................................................................... 40
Ordering Guide .......................................................................... 40
Automotive Products ................................................................. 40