www.DataSheet4U.com

250 kSPS, 12-Bit Impedance Converter,

Network Analyzer

AD5934

FEATURES

Programmable output peak-to-peak excitation voltage

to a max frequency of 100 kHz

Programmable frequency sweep capability with

serial I2C® interface

Frequency resolution of 27 bits (<0.1 Hz)

Impedance measurement range from 100 Ω to 10 MΩ

Phase measurement capability

System accuracy of 0.5%

2.7 V to 5.5 V power supply operation

Temperature range −40°C to +125°C

16-lead SSOP package

APPLICATIONS

Electrochemical analysis

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

GENERAL DESCRIPTION

The AD5934 is a high precision impedance converter system

solution which combines an on-board frequency generator with

a 12-bit, 250 kSPS, analog-to-digital converter (ADC). The

frequency generator allows an external complex impedance to

be excited with a known frequency. The response signal from

the impedance is sampled by the on-board ADC and a discrete

Fourier transform (DFT) is processed by an on-board DSP

engine. The DFT algorithm returns a real (R) and imaginary (I)

data-word at each output frequency.

The magnitude of the impedance and relative phase of the

impedance at each frequency point along the sweep is easily

calculated using the following two equations:

Magnitude = R2 + I2

Phase = Tan−1(I / R)

Table 1. Related Devices

Part No. Description

AD5933 2.7 V to 5.5 V. 1 MSPS, 12-bit impedance, with

internal temperature sensor, 16-lead SSOP.

FUNCTIONAL BLOCK DIAGRAM

MCLK

AVDD

DVDD

SCL

SDA

I2C

INTERFACE

REAL IMAGINARY

REGISTER REGISTER

1024-POINT DFT

DDS

CORE

(27 BITS)

DAC

AD5934

ROUT

VOUT

Z(ω)

RFB

ADC

(12 BITS)

GAIN

LPF

AGND DGND

Figure 1.

VIN

VDD/2

Rev. 0

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 rights of third parties that may result from its use.

Specifications subject to change without notice. No license is granted by implication

or otherwise under any patent or patent rights of Analog Devices. Trademarks and

registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113 © 2005 Analog Devices, Inc. All rights reserved.