pH & Chemical Sensing Applications

National offers precision signal path, temp sensor, and power solutions for pH sensors and chemical sensors as well as Chemical/Gas Sensor AFE:

LMP91000 – Micro-Power Chemical & Gas Sensor AFE

The LMP9100 low-power gas and chemical Sensor AFE provides adjustable bias (sensor drive), sensitivity, and wide dynamic range in an integrated solution for multiple sensing applications. For example, a toxic gas sensing application that today may require several boards and up to 25 components is reduced to just one LMP91000 gas sensor AFE.

• Single analog design for multiple gases and gas concentrations
• Programmable cell bias and TIA gain
• Integrated temperature sensor for external temp monitoring / correction
• Quick design and evaluation
• Ideal for micro-power gas and chemical sensing applications

pH Sensing

Example Solutions

• pH electrode measures hydrogen ion (H+) activity and produces a voltage
• Operating principle - electric potential develops when two liquids of different pH come into contact at opposite sides of a thin glass membrane
• Applications include water treatment, chemical processing, medical instrumentation, and environmental test systems

Chemical Sensing

Example Solutions

• Electro-chemical sensors detect toxic gases
• Electro-chemical sensors are often used in portable equipment to detect different toxic gases (firemen, mining)
• Electro-chemical sensors produce an electrical current that proportional to the gas concentration.
• Interface circuitry (potentiostatic) maintains a constant voltage between the reference electrode and the working electrode. An electro-chemical reaction causes an output signal proportional to the WE current

• Data Conversion
  • Low power MSPS ADCs & DACs
• Amplifiers
  • Precision op amps
• Thermal Management (temps sensors, temp switches, hardware monitors)
• Power Management (including voltage references)