1 MSPS, 12-Bit Impedance Converter, Network Analyzer Data Sheet AD5933 FEATURES GENERAL DESCRIPTION Programmable output peak-to-peak excitation voltage The AD5933 is a high precision impedance converter system to a maximum frequency of 100 kHz solution that combines an on-board frequency generator with Programmable frequency sweep capability with a 12-bit, 1 MSPS, analog-to-digital converter (ADC). The 2 serial I C interface frequency generator allows an external complex impedance to Frequency resolution of 27 bits (<0.1 Hz) be excited with a known frequency. The response signal from Impedance measurement range from 1 k to 10 M the impedance is sampled by the on-board ADC and a discrete Capable of measuring of 100 to 1 k with additional Fourier transform (DFT) is processed by an on-board DSP circuitry engine. The DFT algorithm returns a real (R) and imaginary (I) Internal temperature sensor (2C) data-word at each output frequency. Internal system clock option Once calibrated, the magnitude of the impedance and relative Phase measurement capability phase of the impedance at each frequency point along the sweep System accuracy of 0.5% is easily calculated. This is done off chip using the real and 2.7 V to 5.5 V power supply operation imaginary register contents, which can be read from the serial Temperature range: 40C to +125C 2 I C interface. 16-lead SSOP package Qualified for automotive applications A similar device, also available from Analog Devices, Inc., is the AD5934, a 2.7 V to 5.5 V, 250 kSPS, 12-bit impedance converter, APPLICATIONS with an internal temperature sensor and is packaged in a 16- Electrochemical analysis lead SSOP. Bioelectrical impedance analysis Impedance spectroscopy Complex impedance measurement Corrosion monitoring and protection equipment Biomedical and automotive sensors Proximity sensing Nondestructive testing Material property analysis Fuel/battery cell condition monitoring FUNCTIONAL BLOCK DIAGRAM MCLK AVDD DVDD DDS CORE DAC OSCILLATOR (27 BITS) R VOUT OUT SCL 2 I C TEMPERATURE INTERFACE SENSOR Z() SDA AD5933 REAL IMAGINARY RFB REGISTER REGISTER 1024-POINT DFT VIN ADC GAIN (12 BITS) LPF VDD/2 AGND DGND Figure 1. Rev. F Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20052017 Analog Devices, Inc. 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Technical Support www.analog.com 05324-001AD5933 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Register Map ................................................................................... 23 Applications ....................................................................................... 1 Control Register (Register Address 0x80, Register Address 0x81) ............................................................................................. 23 General Description ......................................................................... 1 Start Frequency Register (Register Address 0x82, Register Functional Block Diagram .............................................................. 1 Address 0x83, Register Address 0x84) .................................... 24 Revision History ............................................................................... 3 Frequency Increment Register (Register Address 0x85, Specifications ..................................................................................... 4 Register Address 0x86, Register Address 0x87) ..................... 25 2 I C Serial Interface Timing Characteristics .............................. 6 Number of Increments Register (Register Address 0x88, Absolute Maximum Ratings ............................................................ 7 Register Address 0x89) .............................................................. 25 ESD Caution .................................................................................. 7 Number of Settling Time Cycles Register (Register Address 0x8A, Register Address 0x8B) ................................................. 25 Pin Configuration and Descriptions .............................................. 8 Status Register (Register Address 0x8F) .................................. 26 Typical Performance Characteristics ............................................. 9 Temperature Data Register (16 BitsRegister Address 0x92, Terminology .................................................................................... 12 Register Address 0x93) .............................................................. 26 System Description ......................................................................... 13 Real and Imaginary Data Registers (16 BitsRegister Transmit Stage ............................................................................. 14 Address 0x94, Register Address 0x95, Register Address 0x96, Frequency Sweep Command Sequence ................................... 15 Register Address 0x97) .............................................................. 26 Receive Stage ............................................................................... 15 Serial Bus Interface ......................................................................... 27 2 DFT Operation ........................................................................... 15 General I C Timing .................................................................... 27 System Clock ............................................................................... 16 Writing/Reading to the AD5933 .............................................. 28 Temperature Sensor ................................................................... 16 Block Write .................................................................................. 28 Temperature Conversion Details .............................................. 16 Read Operations ......................................................................... 29 Temperature Value Register ...................................................... 16 Typical Applications ....................................................................... 30 Temperature Conversion Formula ........................................... 16 Measuring Small Impedances ................................................... 30 Impedance Calculation .................................................................. 17 Biomedical: Noninvasive Blood Impedance Measurement .. 32 Magnitude Calculation .............................................................. 17 Sensor/Complex Impedance Measurement ............................ 32 Gain Factor Calculation ............................................................ 17 Electro-Impedance Spectroscopy ............................................. 33 Impedance Calculation Using Gain Factor ............................. 17 Layout and Configuration ............................................................. 34 Gain Factor Variation with Frequency .................................... 17 Power Supply Bypassing and Grounding ................................ 34 Two-Point Calibration ............................................................... 18 Evaluation Board ............................................................................ 35 Two-Point Gain Factor Calculation ......................................... 18 Using the Evaluation Board ...................................................... 35 Gain Factor Setup Configuration ............................................. 18 Prototyping Area ........................................................................ 35 Gain Factor Recalculation ......................................................... 18 Crystal Oscillator (XO) vs. External Clock ............................. 35 Gain Factor Temperature Variation ......................................... 19 Schematics ................................................................................... 36 Impedance Error ......................................................................... 19 Outline Dimensions ....................................................................... 40 Measuring the Phase Across an Impedance ........................... 19 Ordering Guide .......................................................................... 40 Performing a Frequency Sweep .................................................... 22 Automotive Products ................................................................. 40 Rev. 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