Analog DevicesEVAL-CN0355-PMDZDevelopment Kits and Tools

Reference Design: Low Power, Temperature Compensated Bridge Signal Conditioner and Driver

The EVAL-CN0355-PMDZ is a Pmod interface board with a complete, low power signal conditioner for a bridge type sensor with temperature compensation. This circuit is ideal for a variety of industrial pressure sensors and load cells that operate with drive voltages of between 5 V and 15 V. The circuit can process full-scale signals from approximately 10 mV to 1 V, using the internal programmable gain amplifier (PGA) of the 24-bit, sigma-delta (Σ-Δ) ADC, making it suitable for a wide variety of pressure sensors. The entire circuit uses only three ICs and requires only 1 mA (excluding the bridge current). A ratiometric technique ensures that the accuracy and stability of the system does not depend on a voltage reference.

Block Diagram:  

Features:

• Bridge signal conditioner and driver

• Temperature compensated

• Low power

Applications:

• Battery monitoring

• Portable instrumentation

• Thermocouple measurements

• RTD measurements

• Thermistor measurements

• Gas analysis

• Blood analysis

• Liquid/gas chromatography

Functional Setup

The following equipment is needed to evaluate and test the CN-0355 circuit:

• EVAL-CN0355-PMDZ circuit evaluation board

• EVAL-SDP-CB1Z circuit evaluation board

• SDP-PMD-IB1Z interposer board

• CN0355 Evaluation Software

• Power supply: 6 V wall wart or alternate

• Yokogawa GS200 precision voltage source

• PC with a USB port and Windows® XP and Windows® Vista (32-bit), or Windows® 7 (32-bit)

• Agilent E3631A voltage source

Compatible Boards:

• Intel boards with the Pmod connector 

• EVAL-SDP-CB1Z: Blackfin® (SDP-B) controller board 

• SDP-PMD-IB1Z: Pmod to SDP Adaptor Board

Related ADI parts:

• AD7793: 3-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

• AD8420: Wide Supply Range, Micropower, Rail-to-Rail Instrumentation Amplifier

• ADA4096-2: 30 V, Micropower, Overvoltage Protection, Rail-to-Rail Input/Output Dual Op Amplifier

Reference Documentation:

• ADI Pmod Daughter Cards